/* Line completion stuff for GDB, the GNU debugger. Copyright (C) 2000-2024 Free Software Foundation, Inc. This file is part of GDB. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #include "symtab.h" #include "gdbtypes.h" #include "expression.h" #include "filenames.h" #include "language.h" #include "gdbsupport/gdb_signals.h" #include "target.h" #include "reggroups.h" #include "user-regs.h" #include "arch-utils.h" #include "location.h" #include #include "linespec.h" #include "cli/cli-decode.h" #include "gdbsupport/gdb_tilde_expand.h" /* FIXME: This is needed because of lookup_cmd_1 (). We should be calling a hook instead so we eliminate the CLI dependency. */ #include "gdbcmd.h" /* Needed for rl_completer_word_break_characters and for rl_filename_completion_function. */ #include "readline/readline.h" /* readline defines this. */ #undef savestring #include "completer.h" /* Forward declarations. */ static const char *completion_find_completion_word (completion_tracker &tracker, const char *text, int *quote_char); static void set_rl_completer_word_break_characters (const char *break_chars); /* See completer.h. */ class completion_tracker::completion_hash_entry { public: /* Constructor. */ completion_hash_entry (gdb::unique_xmalloc_ptr name, gdb::unique_xmalloc_ptr lcd) : m_name (std::move (name)), m_lcd (std::move (lcd)) { /* Nothing. */ } /* Returns a pointer to the lowest common denominator string. This string will only be valid while this hash entry is still valid as the string continues to be owned by this hash entry and will be released when this entry is deleted. */ char *get_lcd () const { return m_lcd.get (); } /* Get, and release the name field from this hash entry. This can only be called once, after which the name field is no longer valid. This should be used to pass ownership of the name to someone else. */ char *release_name () { return m_name.release (); } /* Return true of the name in this hash entry is STR. */ bool is_name_eq (const char *str) const { return strcmp (m_name.get (), str) == 0; } /* Return the hash value based on the name of the entry. */ hashval_t hash_name () const { return htab_hash_string (m_name.get ()); } private: /* The symbol name stored in this hash entry. */ gdb::unique_xmalloc_ptr m_name; /* The lowest common denominator string computed for this hash entry. */ gdb::unique_xmalloc_ptr m_lcd; }; /* Misc state that needs to be tracked across several different readline completer entry point calls, all related to a single completion invocation. */ struct gdb_completer_state { /* The current completion's completion tracker. This is a global because a tracker can be shared between the handle_brkchars and handle_completion phases, which involves different readline callbacks. */ completion_tracker *tracker = NULL; /* Whether the current completion was aborted. */ bool aborted = false; }; /* The current completion state. */ static gdb_completer_state current_completion; /* An enumeration of the various things a user might attempt to complete for a location. If you change this, remember to update the explicit_options array below too. */ enum explicit_location_match_type { /* The filename of a source file. */ MATCH_SOURCE, /* The name of a function or method. */ MATCH_FUNCTION, /* The fully-qualified name of a function or method. */ MATCH_QUALIFIED, /* A line number. */ MATCH_LINE, /* The name of a label. */ MATCH_LABEL }; /* Prototypes for local functions. */ /* readline uses the word breaks for two things: (1) In figuring out where to point the TEXT parameter to the rl_completion_entry_function. Since we don't use TEXT for much, it doesn't matter a lot what the word breaks are for this purpose, but it does affect how much stuff M-? lists. (2) If one of the matches contains a word break character, readline will quote it. That's why we switch between current_language->word_break_characters () and gdb_completer_command_word_break_characters. I'm not sure when we need this behavior (perhaps for funky characters in C++ symbols?). */ /* Variables which are necessary for fancy command line editing. */ /* When completing on command names, we remove '-' and '.' from the list of word break characters, since we use it in command names. If the readline library sees one in any of the current completion strings, it thinks that the string needs to be quoted and automatically supplies a leading quote. */ static const char gdb_completer_command_word_break_characters[] = " \t\n!@#$%^&*()+=|~`}{[]\"';:?/><,"; /* When completing on file names, we remove from the list of word break characters any characters that are commonly used in file names, such as '-', '+', '~', etc. Otherwise, readline displays incorrect completion candidates. */ /* MS-DOS and MS-Windows use colon as part of the drive spec, and most programs support @foo style response files. */ static const char gdb_completer_file_name_break_characters[] = #ifdef HAVE_DOS_BASED_FILE_SYSTEM " \t\n*|\"';?><@"; #else " \t\n*|\"';:?><"; #endif /* Characters that can be used to quote expressions. Note that we can't include '"' (double quote) because the gdb C parser treats such quoted sequences as strings. */ static const char gdb_completer_expression_quote_characters[] = "'"; /* Characters that can be used to quote file names. We do allow '"' (double quotes) in this set as file names are not passed through the C expression parser. */ static const char gdb_completer_file_name_quote_characters[] = "'\""; /* This can be used for functions which don't want to complete on symbols but don't want to complete on anything else either. */ void noop_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *prefix) { } /* Complete on filenames. */ void filename_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { rl_completer_quote_characters = gdb_completer_file_name_quote_characters; int subsequent_name = 0; while (1) { gdb::unique_xmalloc_ptr p_rl (rl_filename_completion_function (word, subsequent_name)); if (p_rl == NULL) break; /* We need to set subsequent_name to a non-zero value before the continue line below, because otherwise, if the first file seen by GDB is a backup file whose name ends in a `~', we will loop indefinitely. */ subsequent_name = 1; /* Like emacs, don't complete on old versions. Especially useful in the "source" command. */ const char *p = p_rl.get (); if (p[strlen (p) - 1] == '~') continue; /* Readline appends a trailing '/' if the completion is a directory. If this completion request originated from outside readline (e.g. GDB's 'complete' command), then we append the trailing '/' ourselves now. */ if (!tracker.from_readline ()) { std::string expanded = gdb_tilde_expand (p_rl.get ()); struct stat finfo; const bool isdir = (stat (expanded.c_str (), &finfo) == 0 && S_ISDIR (finfo.st_mode)); if (isdir) p_rl.reset (concat (p_rl.get (), "/", nullptr)); } tracker.add_completion (make_completion_match_str (std::move (p_rl), word, word)); } } /* The corresponding completer_handle_brkchars implementation. */ static void filename_completer_handle_brkchars (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { set_rl_completer_word_break_characters (gdb_completer_file_name_break_characters); rl_completer_quote_characters = gdb_completer_file_name_quote_characters; } /* Find the bounds of the current word for completion purposes, and return a pointer to the end of the word. This mimics (and is a modified version of) readline's _rl_find_completion_word internal function. This function skips quoted substrings (characters between matched pairs of characters in rl_completer_quote_characters). We try to find an unclosed quoted substring on which to do matching. If one is not found, we use the word break characters to find the boundaries of the current word. QC, if non-null, is set to the opening quote character if we found an unclosed quoted substring, '\0' otherwise. DP, if non-null, is set to the value of the delimiter character that caused a word break. */ struct gdb_rl_completion_word_info { const char *word_break_characters; const char *quote_characters; const char *basic_quote_characters; }; static const char * gdb_rl_find_completion_word (struct gdb_rl_completion_word_info *info, int *qc, int *dp, const char *line_buffer) { int scan, end, delimiter, pass_next, isbrk; char quote_char; const char *brkchars; int point = strlen (line_buffer); /* The algorithm below does '--point'. Avoid buffer underflow with the empty string. */ if (point == 0) { if (qc != NULL) *qc = '\0'; if (dp != NULL) *dp = '\0'; return line_buffer; } end = point; delimiter = 0; quote_char = '\0'; brkchars = info->word_break_characters; if (info->quote_characters != NULL) { /* We have a list of characters which can be used in pairs to quote substrings for the completer. Try to find the start of an unclosed quoted substring. */ for (scan = pass_next = 0; scan < end; scan++) { if (pass_next) { pass_next = 0; continue; } /* Shell-like semantics for single quotes -- don't allow backslash to quote anything in single quotes, especially not the closing quote. If you don't like this, take out the check on the value of quote_char. */ if (quote_char != '\'' && line_buffer[scan] == '\\') { pass_next = 1; continue; } if (quote_char != '\0') { /* Ignore everything until the matching close quote char. */ if (line_buffer[scan] == quote_char) { /* Found matching close. Abandon this substring. */ quote_char = '\0'; point = end; } } else if (strchr (info->quote_characters, line_buffer[scan])) { /* Found start of a quoted substring. */ quote_char = line_buffer[scan]; point = scan + 1; } } } if (point == end && quote_char == '\0') { /* We didn't find an unclosed quoted substring upon which to do completion, so use the word break characters to find the substring on which to complete. */ while (--point) { scan = line_buffer[point]; if (strchr (brkchars, scan) != 0) break; } } /* If we are at an unquoted word break, then advance past it. */ scan = line_buffer[point]; if (scan) { isbrk = strchr (brkchars, scan) != 0; if (isbrk) { /* If the character that caused the word break was a quoting character, then remember it as the delimiter. */ if (info->basic_quote_characters && strchr (info->basic_quote_characters, scan) && (end - point) > 1) delimiter = scan; point++; } } if (qc != NULL) *qc = quote_char; if (dp != NULL) *dp = delimiter; return line_buffer + point; } /* Find the completion word point for TEXT, emulating the algorithm readline uses to find the word point, using WORD_BREAK_CHARACTERS as word break characters. */ static const char * advance_to_completion_word (completion_tracker &tracker, const char *word_break_characters, const char *quote_characters, const char *text) { gdb_rl_completion_word_info info; info.word_break_characters = word_break_characters; info.quote_characters = quote_characters; info.basic_quote_characters = rl_basic_quote_characters; int delimiter; const char *start = gdb_rl_find_completion_word (&info, NULL, &delimiter, text); tracker.advance_custom_word_point_by (start - text); if (delimiter) { tracker.set_quote_char (delimiter); tracker.set_suppress_append_ws (true); } return start; } /* See completer.h. */ const char * advance_to_expression_complete_word_point (completion_tracker &tracker, const char *text) { const char *brk_chars = current_language->word_break_characters (); const char *quote_chars = gdb_completer_expression_quote_characters; return advance_to_completion_word (tracker, brk_chars, quote_chars, text); } /* See completer.h. */ const char * advance_to_filename_complete_word_point (completion_tracker &tracker, const char *text) { const char *brk_chars = gdb_completer_file_name_break_characters; const char *quote_chars = gdb_completer_file_name_quote_characters; return advance_to_completion_word (tracker, brk_chars, quote_chars, text); } /* See completer.h. */ bool completion_tracker::completes_to_completion_word (const char *word) { recompute_lowest_common_denominator (); if (m_lowest_common_denominator_unique) { const char *lcd = m_lowest_common_denominator; if (strncmp_iw (word, lcd, strlen (lcd)) == 0) { /* Maybe skip the function and complete on keywords. */ size_t wordlen = strlen (word); if (word[wordlen - 1] == ' ') return true; } } return false; } /* See completer.h. */ void complete_nested_command_line (completion_tracker &tracker, const char *text) { /* Must be called from a custom-word-point completer. */ gdb_assert (tracker.use_custom_word_point ()); /* Disable the custom word point temporarily, because we want to probe whether the command we're completing itself uses a custom word point. */ tracker.set_use_custom_word_point (false); size_t save_custom_word_point = tracker.custom_word_point (); int quote_char = '\0'; const char *word = completion_find_completion_word (tracker, text, "e_char); if (tracker.use_custom_word_point ()) { /* The command we're completing uses a custom word point, so the tracker already contains the matches. We're done. */ return; } /* Restore the custom word point settings. */ tracker.set_custom_word_point (save_custom_word_point); tracker.set_use_custom_word_point (true); /* Run the handle_completions completer phase. */ complete_line (tracker, word, text, strlen (text)); } /* Complete on linespecs, which might be of two possible forms: file:line or symbol+offset This is intended to be used in commands that set breakpoints etc. */ static void complete_files_symbols (completion_tracker &tracker, const char *text, const char *word) { completion_list fn_list; const char *p; int quote_found = 0; int quoted = *text == '\'' || *text == '"'; int quote_char = '\0'; const char *colon = NULL; char *file_to_match = NULL; const char *symbol_start = text; const char *orig_text = text; /* Do we have an unquoted colon, as in "break foo.c:bar"? */ for (p = text; *p != '\0'; ++p) { if (*p == '\\' && p[1] == '\'') p++; else if (*p == '\'' || *p == '"') { quote_found = *p; quote_char = *p++; while (*p != '\0' && *p != quote_found) { if (*p == '\\' && p[1] == quote_found) p++; p++; } if (*p == quote_found) quote_found = 0; else break; /* Hit the end of text. */ } #if HAVE_DOS_BASED_FILE_SYSTEM /* If we have a DOS-style absolute file name at the beginning of TEXT, and the colon after the drive letter is the only colon we found, pretend the colon is not there. */ else if (p < text + 3 && *p == ':' && p == text + 1 + quoted) ; #endif else if (*p == ':' && !colon) { colon = p; symbol_start = p + 1; } else if (strchr (current_language->word_break_characters (), *p)) symbol_start = p + 1; } if (quoted) text++; /* Where is the file name? */ if (colon) { char *s; file_to_match = (char *) xmalloc (colon - text + 1); strncpy (file_to_match, text, colon - text); file_to_match[colon - text] = '\0'; /* Remove trailing colons and quotes from the file name. */ for (s = file_to_match + (colon - text); s > file_to_match; s--) if (*s == ':' || *s == quote_char) *s = '\0'; } /* If the text includes a colon, they want completion only on a symbol name after the colon. Otherwise, we need to complete on symbols as well as on files. */ if (colon) { collect_file_symbol_completion_matches (tracker, complete_symbol_mode::EXPRESSION, symbol_name_match_type::EXPRESSION, symbol_start, word, file_to_match); xfree (file_to_match); } else { size_t text_len = strlen (text); collect_symbol_completion_matches (tracker, complete_symbol_mode::EXPRESSION, symbol_name_match_type::EXPRESSION, symbol_start, word); /* If text includes characters which cannot appear in a file name, they cannot be asking for completion on files. */ if (strcspn (text, gdb_completer_file_name_break_characters) == text_len) fn_list = make_source_files_completion_list (text, text); } if (!fn_list.empty () && !tracker.have_completions ()) { /* If we only have file names as possible completion, we should bring them in sync with what rl_complete expects. The problem is that if the user types "break /foo/b TAB", and the possible completions are "/foo/bar" and "/foo/baz" rl_complete expects us to return "bar" and "baz", without the leading directories, as possible completions, because `word' starts at the "b". But we ignore the value of `word' when we call make_source_files_completion_list above (because that would not DTRT when the completion results in both symbols and file names), so make_source_files_completion_list returns the full "/foo/bar" and "/foo/baz" strings. This produces wrong results when, e.g., there's only one possible completion, because rl_complete will prepend "/foo/" to each candidate completion. The loop below removes that leading part. */ for (const auto &fn_up: fn_list) { char *fn = fn_up.get (); memmove (fn, fn + (word - text), strlen (fn) + 1 - (word - text)); } } tracker.add_completions (std::move (fn_list)); if (!tracker.have_completions ()) { /* No completions at all. As the final resort, try completing on the entire text as a symbol. */ collect_symbol_completion_matches (tracker, complete_symbol_mode::EXPRESSION, symbol_name_match_type::EXPRESSION, orig_text, word); } } /* See completer.h. */ completion_list complete_source_filenames (const char *text) { size_t text_len = strlen (text); /* If text includes characters which cannot appear in a file name, the user cannot be asking for completion on files. */ if (strcspn (text, gdb_completer_file_name_break_characters) == text_len) return make_source_files_completion_list (text, text); return {}; } /* Complete address and linespec locations. */ static void complete_address_and_linespec_locations (completion_tracker &tracker, const char *text, symbol_name_match_type match_type) { if (*text == '*') { tracker.advance_custom_word_point_by (1); text++; const char *word = advance_to_expression_complete_word_point (tracker, text); complete_expression (tracker, text, word); } else { linespec_complete (tracker, text, match_type); } } /* The explicit location options. Note that indexes into this array must match the explicit_location_match_type enumerators. */ static const char *const explicit_options[] = { "-source", "-function", "-qualified", "-line", "-label", NULL }; /* The probe modifier options. These can appear before a location in breakpoint commands. */ static const char *const probe_options[] = { "-probe", "-probe-stap", "-probe-dtrace", NULL }; /* Returns STRING if not NULL, the empty string otherwise. */ static const char * string_or_empty (const char *string) { return string != NULL ? string : ""; } /* A helper function to collect explicit location matches for the given LOCATION, which is attempting to match on WORD. */ static void collect_explicit_location_matches (completion_tracker &tracker, location_spec *locspec, enum explicit_location_match_type what, const char *word, const struct language_defn *language) { const explicit_location_spec *explicit_loc = as_explicit_location_spec (locspec); /* True if the option expects an argument. */ bool needs_arg = true; /* Note, in the various MATCH_* below, we complete on explicit_loc->foo instead of WORD, because only the former will have already skipped past any quote char. */ switch (what) { case MATCH_SOURCE: { const char *source = string_or_empty (explicit_loc->source_filename.get ()); completion_list matches = make_source_files_completion_list (source, source); tracker.add_completions (std::move (matches)); } break; case MATCH_FUNCTION: { const char *function = string_or_empty (explicit_loc->function_name.get ()); linespec_complete_function (tracker, function, explicit_loc->func_name_match_type, explicit_loc->source_filename.get ()); } break; case MATCH_QUALIFIED: needs_arg = false; break; case MATCH_LINE: /* Nothing to offer. */ break; case MATCH_LABEL: { const char *label = string_or_empty (explicit_loc->label_name.get ()); linespec_complete_label (tracker, language, explicit_loc->source_filename.get (), explicit_loc->function_name.get (), explicit_loc->func_name_match_type, label); } break; default: gdb_assert_not_reached ("unhandled explicit_location_match_type"); } if (!needs_arg || tracker.completes_to_completion_word (word)) { tracker.discard_completions (); tracker.advance_custom_word_point_by (strlen (word)); complete_on_enum (tracker, explicit_options, "", ""); complete_on_enum (tracker, linespec_keywords, "", ""); } else if (!tracker.have_completions ()) { /* Maybe we have an unterminated linespec keyword at the tail of the string. Try completing on that. */ size_t wordlen = strlen (word); const char *keyword = word + wordlen; if (wordlen > 0 && keyword[-1] != ' ') { while (keyword > word && *keyword != ' ') keyword--; /* Don't complete on keywords if we'd be completing on the whole explicit linespec option. E.g., "b -function thr" should not complete to the "thread" keyword. */ if (keyword != word) { keyword = skip_spaces (keyword); tracker.advance_custom_word_point_by (keyword - word); complete_on_enum (tracker, linespec_keywords, keyword, keyword); } } else if (wordlen > 0 && keyword[-1] == ' ') { /* Assume that we're maybe past the explicit location argument, and we didn't manage to find any match because the user wants to create a pending breakpoint. Offer the keyword and explicit location options as possible completions. */ tracker.advance_custom_word_point_by (keyword - word); complete_on_enum (tracker, linespec_keywords, keyword, keyword); complete_on_enum (tracker, explicit_options, keyword, keyword); } } } /* If the next word in *TEXT_P is any of the keywords in KEYWORDS, then advance both TEXT_P and the word point in the tracker past the keyword and return the (0-based) index in the KEYWORDS array that matched. Otherwise, return -1. */ static int skip_keyword (completion_tracker &tracker, const char * const *keywords, const char **text_p) { const char *text = *text_p; const char *after = skip_to_space (text); size_t len = after - text; if (text[len] != ' ') return -1; int found = -1; for (int i = 0; keywords[i] != NULL; i++) { if (strncmp (keywords[i], text, len) == 0) { if (found == -1) found = i; else return -1; } } if (found != -1) { tracker.advance_custom_word_point_by (len + 1); text += len + 1; *text_p = text; return found; } return -1; } /* A completer function for explicit location specs. This function completes both options ("-source", "-line", etc) and values. If completing a quoted string, then QUOTED_ARG_START and QUOTED_ARG_END point to the quote characters. LANGUAGE is the current language. */ static void complete_explicit_location_spec (completion_tracker &tracker, location_spec *locspec, const char *text, const language_defn *language, const char *quoted_arg_start, const char *quoted_arg_end) { if (*text != '-') return; int keyword = skip_keyword (tracker, explicit_options, &text); if (keyword == -1) { complete_on_enum (tracker, explicit_options, text, text); /* There are keywords that start with "-". Include them, too. */ complete_on_enum (tracker, linespec_keywords, text, text); } else { /* Completing on value. */ enum explicit_location_match_type what = (explicit_location_match_type) keyword; if (quoted_arg_start != NULL && quoted_arg_end != NULL) { if (quoted_arg_end[1] == '\0') { /* If completing a quoted string with the cursor right at the terminating quote char, complete the completion word without interpretation, so that readline advances the cursor one whitespace past the quote, even if there's no match. This makes these cases behave the same: before: "b -function function()" after: "b -function function() " before: "b -function 'function()'" after: "b -function 'function()' " and trusts the user in this case: before: "b -function 'not_loaded_function_yet()'" after: "b -function 'not_loaded_function_yet()' " */ tracker.add_completion (make_unique_xstrdup (text)); } else if (quoted_arg_end[1] == ' ') { /* We're maybe past the explicit location argument. Skip the argument without interpretation, assuming the user may want to create pending breakpoint. Offer the keyword and explicit location options as possible completions. */ tracker.advance_custom_word_point_by (strlen (text)); complete_on_enum (tracker, linespec_keywords, "", ""); complete_on_enum (tracker, explicit_options, "", ""); } return; } /* Now gather matches */ collect_explicit_location_matches (tracker, locspec, what, text, language); } } /* A completer for locations. */ void location_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char * /* word */) { int found_probe_option = -1; /* If we have a probe modifier, skip it. This can only appear as first argument. Until we have a specific completer for probes, falling back to the linespec completer for the remainder of the line is better than nothing. */ if (text[0] == '-' && text[1] == 'p') found_probe_option = skip_keyword (tracker, probe_options, &text); const char *option_text = text; int saved_word_point = tracker.custom_word_point (); const char *copy = text; explicit_completion_info completion_info; location_spec_up locspec = string_to_explicit_location_spec (©, current_language, &completion_info); if (completion_info.quoted_arg_start != NULL && completion_info.quoted_arg_end == NULL) { /* Found an unbalanced quote. */ tracker.set_quote_char (*completion_info.quoted_arg_start); tracker.advance_custom_word_point_by (1); } if (completion_info.saw_explicit_location_spec_option) { if (*copy != '\0') { tracker.advance_custom_word_point_by (copy - text); text = copy; /* We found a terminator at the tail end of the string, which means we're past the explicit location options. We may have a keyword to complete on. If we have a whole keyword, then complete whatever comes after as an expression. This is mainly for the "if" keyword. If the "thread" and "task" keywords gain their own completers, they should be used here. */ int keyword = skip_keyword (tracker, linespec_keywords, &text); if (keyword == -1) { complete_on_enum (tracker, linespec_keywords, text, text); } else { const char *word = advance_to_expression_complete_word_point (tracker, text); complete_expression (tracker, text, word); } } else { tracker.advance_custom_word_point_by (completion_info.last_option - text); text = completion_info.last_option; complete_explicit_location_spec (tracker, locspec.get (), text, current_language, completion_info.quoted_arg_start, completion_info.quoted_arg_end); } } /* This is an address or linespec location. */ else if (locspec != nullptr) { /* Handle non-explicit location options. */ int keyword = skip_keyword (tracker, explicit_options, &text); if (keyword == -1) complete_on_enum (tracker, explicit_options, text, text); else { tracker.advance_custom_word_point_by (copy - text); text = copy; symbol_name_match_type match_type = as_explicit_location_spec (locspec.get ())->func_name_match_type; complete_address_and_linespec_locations (tracker, text, match_type); } } else { /* No options. */ complete_address_and_linespec_locations (tracker, text, symbol_name_match_type::WILD); } /* Add matches for option names, if either: - Some completer above found some matches, but the word point did not advance (e.g., "b " finds all functions, or "b -" matches all objc selectors), or; - Some completer above advanced the word point, but found no matches. */ if ((text[0] == '-' || text[0] == '\0') && (!tracker.have_completions () || tracker.custom_word_point () == saved_word_point)) { tracker.set_custom_word_point (saved_word_point); text = option_text; if (found_probe_option == -1) complete_on_enum (tracker, probe_options, text, text); complete_on_enum (tracker, explicit_options, text, text); } } /* The corresponding completer_handle_brkchars implementation. */ static void location_completer_handle_brkchars (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word_ignored) { tracker.set_use_custom_word_point (true); location_completer (ignore, tracker, text, NULL); } /* See completer.h. */ void complete_expression (completion_tracker &tracker, const char *text, const char *word) { expression_up exp; std::unique_ptr expr_completer; /* Perform a tentative parse of the expression, to see whether a field completion is required. */ try { exp = parse_expression_for_completion (text, &expr_completer); } catch (const gdb_exception_error &except) { return; } /* Part of the parse_expression_for_completion contract. */ gdb_assert ((exp == nullptr) == (expr_completer == nullptr)); if (expr_completer != nullptr && expr_completer->complete (exp.get (), tracker)) return; complete_files_symbols (tracker, text, word); } /* Complete on expressions. Often this means completing on symbol names, but some language parsers also have support for completing field names. */ void expression_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { complete_expression (tracker, text, word); } /* Set the word break characters array to BREAK_CHARS. This function is useful as const-correct alternative to direct assignment to rl_completer_word_break_characters, which is "char *", not "const char *". */ static void set_rl_completer_word_break_characters (const char *break_chars) { rl_completer_word_break_characters = (char *) break_chars; } /* Complete on symbols. */ void symbol_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { collect_symbol_completion_matches (tracker, complete_symbol_mode::EXPRESSION, symbol_name_match_type::EXPRESSION, text, word); } /* Here are some useful test cases for completion. FIXME: These should be put in the test suite. They should be tested with both M-? and TAB. "show output-" "radix" "show output" "-radix" "p" ambiguous (commands starting with p--path, print, printf, etc.) "p " ambiguous (all symbols) "info t foo" no completions "info t " no completions "info t" ambiguous ("info target", "info terminal", etc.) "info ajksdlfk" no completions "info ajksdlfk " no completions "info" " " "info " ambiguous (all info commands) "p \"a" no completions (string constant) "p 'a" ambiguous (all symbols starting with a) "p b-a" ambiguous (all symbols starting with a) "p b-" ambiguous (all symbols) "file Make" "file" (word break hard to screw up here) "file ../gdb.stabs/we" "ird" (needs to not break word at slash) */ enum complete_line_internal_reason { /* Preliminary phase, called by gdb_completion_word_break_characters function, is used to either: #1 - Determine the set of chars that are word delimiters depending on the current command in line_buffer. #2 - Manually advance RL_POINT to the "word break" point instead of letting readline do it (based on too-simple character matching). Simpler completers that just pass a brkchars array to readline (#1 above) must defer generating the completions to the main phase (below). No completion list should be generated in this phase. OTOH, completers that manually advance the word point(#2 above) must set "use_custom_word_point" in the tracker and generate their completion in this phase. Note that this is the convenient thing to do since they'll be parsing the input line anyway. */ handle_brkchars, /* Main phase, called by complete_line function, is used to get the list of possible completions. */ handle_completions, /* Special case when completing a 'help' command. In this case, once sub-command completions are exhausted, we simply return NULL. */ handle_help, }; /* Helper for complete_line_internal to simplify it. */ static void complete_line_internal_normal_command (completion_tracker &tracker, const char *command, const char *word, const char *cmd_args, complete_line_internal_reason reason, struct cmd_list_element *c) { if (reason == handle_brkchars) { completer_handle_brkchars_ftype *brkchars_fn; if (c->completer_handle_brkchars != NULL) brkchars_fn = c->completer_handle_brkchars; else { brkchars_fn = (completer_handle_brkchars_func_for_completer (c->completer)); } brkchars_fn (c, tracker, cmd_args, word); } if (reason != handle_brkchars && c->completer != NULL) (*c->completer) (c, tracker, cmd_args, word); } /* Internal function used to handle completions. TEXT is the caller's idea of the "word" we are looking at. LINE_BUFFER is available to be looked at; it contains the entire text of the line. POINT is the offset in that line of the cursor. You should pretend that the line ends at POINT. See complete_line_internal_reason for description of REASON. */ static void complete_line_internal_1 (completion_tracker &tracker, const char *text, const char *line_buffer, int point, complete_line_internal_reason reason) { char *tmp_command; const char *p; int ignore_help_classes; /* Pointer within tmp_command which corresponds to text. */ const char *word; struct cmd_list_element *c, *result_list; /* Choose the default set of word break characters to break completions. If we later find out that we are doing completions on command strings (as opposed to strings supplied by the individual command completer functions, which can be any string) then we will switch to the special word break set for command strings, which leaves out the '-' and '.' character used in some commands. */ set_rl_completer_word_break_characters (current_language->word_break_characters ()); /* Likewise for the quote characters. If we later find out that we are completing file names then we can switch to the file name quote character set (i.e., both single- and double-quotes). */ rl_completer_quote_characters = gdb_completer_expression_quote_characters; /* Decide whether to complete on a list of gdb commands or on symbols. */ tmp_command = (char *) alloca (point + 1); p = tmp_command; /* The help command should complete help aliases. */ ignore_help_classes = reason != handle_help; strncpy (tmp_command, line_buffer, point); tmp_command[point] = '\0'; if (reason == handle_brkchars) { gdb_assert (text == NULL); word = NULL; } else { /* Since text always contains some number of characters leading up to point, we can find the equivalent position in tmp_command by subtracting that many characters from the end of tmp_command. */ word = tmp_command + point - strlen (text); } /* Move P up to the start of the command. */ p = skip_spaces (p); if (*p == '\0') { /* An empty line is ambiguous; that is, it could be any command. */ c = CMD_LIST_AMBIGUOUS; result_list = 0; } else c = lookup_cmd_1 (&p, cmdlist, &result_list, NULL, ignore_help_classes, true); /* Move p up to the next interesting thing. */ while (*p == ' ' || *p == '\t') { p++; } tracker.advance_custom_word_point_by (p - tmp_command); if (!c) { /* It is an unrecognized command. So there are no possible completions. */ } else if (c == CMD_LIST_AMBIGUOUS) { const char *q; /* lookup_cmd_1 advances p up to the first ambiguous thing, but doesn't advance over that thing itself. Do so now. */ q = p; while (valid_cmd_char_p (*q)) ++q; if (q != tmp_command + point) { /* There is something beyond the ambiguous command, so there are no possible completions. For example, "info t " or "info t foo" does not complete to anything, because "info t" can be "info target" or "info terminal". */ } else { /* We're trying to complete on the command which was ambiguous. This we can deal with. */ if (result_list) { if (reason != handle_brkchars) complete_on_cmdlist (*result_list->subcommands, tracker, p, word, ignore_help_classes); } else { if (reason != handle_brkchars) complete_on_cmdlist (cmdlist, tracker, p, word, ignore_help_classes); } /* Ensure that readline does the right thing with respect to inserting quotes. */ set_rl_completer_word_break_characters (gdb_completer_command_word_break_characters); } } else { /* We've recognized a full command. */ if (p == tmp_command + point) { /* There is no non-whitespace in the line beyond the command. */ if (p[-1] == ' ' || p[-1] == '\t') { /* The command is followed by whitespace; we need to complete on whatever comes after command. */ if (c->is_prefix ()) { /* It is a prefix command; what comes after it is a subcommand (e.g. "info "). */ if (reason != handle_brkchars) complete_on_cmdlist (*c->subcommands, tracker, p, word, ignore_help_classes); /* Ensure that readline does the right thing with respect to inserting quotes. */ set_rl_completer_word_break_characters (gdb_completer_command_word_break_characters); } else if (reason == handle_help) ; else if (c->enums) { if (reason != handle_brkchars) complete_on_enum (tracker, c->enums, p, word); set_rl_completer_word_break_characters (gdb_completer_command_word_break_characters); } else { /* It is a normal command; what comes after it is completed by the command's completer function. */ complete_line_internal_normal_command (tracker, tmp_command, word, p, reason, c); } } else { /* The command is not followed by whitespace; we need to complete on the command itself, e.g. "p" which is a command itself but also can complete to "print", "ptype" etc. */ const char *q; /* Find the command we are completing on. */ q = p; while (q > tmp_command) { if (valid_cmd_char_p (q[-1])) --q; else break; } /* Move the custom word point back too. */ tracker.advance_custom_word_point_by (q - p); if (reason != handle_brkchars) complete_on_cmdlist (result_list, tracker, q, word, ignore_help_classes); /* Ensure that readline does the right thing with respect to inserting quotes. */ set_rl_completer_word_break_characters (gdb_completer_command_word_break_characters); } } else if (reason == handle_help) ; else { /* There is non-whitespace beyond the command. */ if (c->is_prefix () && !c->allow_unknown) { /* It is an unrecognized subcommand of a prefix command, e.g. "info adsfkdj". */ } else if (c->enums) { if (reason != handle_brkchars) complete_on_enum (tracker, c->enums, p, word); } else { /* It is a normal command. */ complete_line_internal_normal_command (tracker, tmp_command, word, p, reason, c); } } } } /* Wrapper around complete_line_internal_1 to handle MAX_COMPLETIONS_REACHED_ERROR. */ static void complete_line_internal (completion_tracker &tracker, const char *text, const char *line_buffer, int point, complete_line_internal_reason reason) { try { complete_line_internal_1 (tracker, text, line_buffer, point, reason); } catch (const gdb_exception_error &except) { if (except.error != MAX_COMPLETIONS_REACHED_ERROR) throw; } } /* See completer.h. */ int max_completions = 200; /* Initial size of the table. It automagically grows from here. */ #define INITIAL_COMPLETION_HTAB_SIZE 200 /* See completer.h. */ completion_tracker::completion_tracker (bool from_readline) : m_from_readline (from_readline) { discard_completions (); } /* See completer.h. */ void completion_tracker::discard_completions () { xfree (m_lowest_common_denominator); m_lowest_common_denominator = NULL; m_lowest_common_denominator_unique = false; m_lowest_common_denominator_valid = false; m_entries_hash.reset (nullptr); /* A callback used by the hash table to compare new entries with existing entries. We can't use the standard htab_eq_string function here as the key to our hash is just a single string, while the values we store in the hash are a struct containing multiple strings. */ static auto entry_eq_func = [] (const void *first, const void *second) -> int { /* The FIRST argument is the entry already in the hash table, and the SECOND argument is the new item being inserted. */ const completion_hash_entry *entry = (const completion_hash_entry *) first; const char *name_str = (const char *) second; return entry->is_name_eq (name_str); }; /* Callback used by the hash table to compute the hash value for an existing entry. This is needed when expanding the hash table. */ static auto entry_hash_func = [] (const void *arg) -> hashval_t { const completion_hash_entry *entry = (const completion_hash_entry *) arg; return entry->hash_name (); }; m_entries_hash.reset (htab_create_alloc (INITIAL_COMPLETION_HTAB_SIZE, entry_hash_func, entry_eq_func, htab_delete_entry, xcalloc, xfree)); } /* See completer.h. */ completion_tracker::~completion_tracker () { xfree (m_lowest_common_denominator); } /* See completer.h. */ bool completion_tracker::maybe_add_completion (gdb::unique_xmalloc_ptr name, completion_match_for_lcd *match_for_lcd, const char *text, const char *word) { void **slot; if (max_completions == 0) return false; if (htab_elements (m_entries_hash.get ()) >= max_completions) return false; hashval_t hash = htab_hash_string (name.get ()); slot = htab_find_slot_with_hash (m_entries_hash.get (), name.get (), hash, INSERT); if (*slot == HTAB_EMPTY_ENTRY) { const char *match_for_lcd_str = NULL; if (match_for_lcd != NULL) match_for_lcd_str = match_for_lcd->finish (); if (match_for_lcd_str == NULL) match_for_lcd_str = name.get (); gdb::unique_xmalloc_ptr lcd = make_completion_match_str (match_for_lcd_str, text, word); size_t lcd_len = strlen (lcd.get ()); *slot = new completion_hash_entry (std::move (name), std::move (lcd)); m_lowest_common_denominator_valid = false; m_lowest_common_denominator_max_length = std::max (m_lowest_common_denominator_max_length, lcd_len); } return true; } /* See completer.h. */ void completion_tracker::add_completion (gdb::unique_xmalloc_ptr name, completion_match_for_lcd *match_for_lcd, const char *text, const char *word) { if (!maybe_add_completion (std::move (name), match_for_lcd, text, word)) throw_error (MAX_COMPLETIONS_REACHED_ERROR, _("Max completions reached.")); } /* See completer.h. */ void completion_tracker::add_completions (completion_list &&list) { for (auto &candidate : list) add_completion (std::move (candidate)); } /* See completer.h. */ void completion_tracker::remove_completion (const char *name) { hashval_t hash = htab_hash_string (name); if (htab_find_slot_with_hash (m_entries_hash.get (), name, hash, NO_INSERT) != NULL) { htab_remove_elt_with_hash (m_entries_hash.get (), name, hash); m_lowest_common_denominator_valid = false; } } /* Helper for the make_completion_match_str overloads. Returns NULL as an indication that we want MATCH_NAME exactly. It is up to the caller to xstrdup that string if desired. */ static char * make_completion_match_str_1 (const char *match_name, const char *text, const char *word) { char *newobj; if (word == text) { /* Return NULL as an indication that we want MATCH_NAME exactly. */ return NULL; } else if (word > text) { /* Return some portion of MATCH_NAME. */ newobj = xstrdup (match_name + (word - text)); } else { /* Return some of WORD plus MATCH_NAME. */ size_t len = strlen (match_name); newobj = (char *) xmalloc (text - word + len + 1); memcpy (newobj, word, text - word); memcpy (newobj + (text - word), match_name, len + 1); } return newobj; } /* See completer.h. */ gdb::unique_xmalloc_ptr make_completion_match_str (const char *match_name, const char *text, const char *word) { char *newobj = make_completion_match_str_1 (match_name, text, word); if (newobj == NULL) newobj = xstrdup (match_name); return gdb::unique_xmalloc_ptr (newobj); } /* See completer.h. */ gdb::unique_xmalloc_ptr make_completion_match_str (gdb::unique_xmalloc_ptr &&match_name, const char *text, const char *word) { char *newobj = make_completion_match_str_1 (match_name.get (), text, word); if (newobj == NULL) return std::move (match_name); return gdb::unique_xmalloc_ptr (newobj); } /* See complete.h. */ completion_result complete (const char *line, char const **word, int *quote_char) { completion_tracker tracker_handle_brkchars (false); completion_tracker tracker_handle_completions (false); completion_tracker *tracker; /* The WORD should be set to the end of word to complete. We initialize to the completion point which is assumed to be at the end of LINE. This leaves WORD to be initialized to a sensible value in cases completion_find_completion_word() fails i.e., throws an exception. See bug 24587. */ *word = line + strlen (line); try { *word = completion_find_completion_word (tracker_handle_brkchars, line, quote_char); /* Completers that provide a custom word point in the handle_brkchars phase also compute their completions then. Completers that leave the completion word handling to readline must be called twice. */ if (tracker_handle_brkchars.use_custom_word_point ()) tracker = &tracker_handle_brkchars; else { complete_line (tracker_handle_completions, *word, line, strlen (line)); tracker = &tracker_handle_completions; } } catch (const gdb_exception &ex) { return {}; } return tracker->build_completion_result (*word, *word - line, strlen (line)); } /* Generate completions all at once. Does nothing if max_completions is 0. If max_completions is non-negative, this will collect at most max_completions strings. TEXT is the caller's idea of the "word" we are looking at. LINE_BUFFER is available to be looked at; it contains the entire text of the line. POINT is the offset in that line of the cursor. You should pretend that the line ends at POINT. */ void complete_line (completion_tracker &tracker, const char *text, const char *line_buffer, int point) { if (max_completions == 0) return; complete_line_internal (tracker, text, line_buffer, point, handle_completions); } /* Complete on command names. Used by "help". */ void command_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { complete_line_internal (tracker, word, text, strlen (text), handle_help); } /* The corresponding completer_handle_brkchars implementation. */ static void command_completer_handle_brkchars (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { set_rl_completer_word_break_characters (gdb_completer_command_word_break_characters); } /* Complete on signals. */ void signal_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { size_t len = strlen (word); int signum; const char *signame; for (signum = GDB_SIGNAL_FIRST; signum != GDB_SIGNAL_LAST; ++signum) { /* Can't handle this, so skip it. */ if (signum == GDB_SIGNAL_0) continue; signame = gdb_signal_to_name ((enum gdb_signal) signum); /* Ignore the unknown signal case. */ if (!signame || strcmp (signame, "?") == 0) continue; if (strncasecmp (signame, word, len) == 0) tracker.add_completion (make_unique_xstrdup (signame)); } } /* Bit-flags for selecting what the register and/or register-group completer should complete on. */ enum reg_completer_target { complete_register_names = 0x1, complete_reggroup_names = 0x2 }; DEF_ENUM_FLAGS_TYPE (enum reg_completer_target, reg_completer_targets); /* Complete register names and/or reggroup names based on the value passed in TARGETS. At least one bit in TARGETS must be set. */ static void reg_or_group_completer_1 (completion_tracker &tracker, const char *text, const char *word, reg_completer_targets targets) { size_t len = strlen (word); struct gdbarch *gdbarch; const char *name; gdb_assert ((targets & (complete_register_names | complete_reggroup_names)) != 0); gdbarch = get_current_arch (); if ((targets & complete_register_names) != 0) { int i; for (i = 0; (name = user_reg_map_regnum_to_name (gdbarch, i)) != NULL; i++) { if (*name != '\0' && strncmp (word, name, len) == 0) tracker.add_completion (make_unique_xstrdup (name)); } } if ((targets & complete_reggroup_names) != 0) { for (const struct reggroup *group : gdbarch_reggroups (gdbarch)) { name = group->name (); if (strncmp (word, name, len) == 0) tracker.add_completion (make_unique_xstrdup (name)); } } } /* Perform completion on register and reggroup names. */ void reg_or_group_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { reg_or_group_completer_1 (tracker, text, word, (complete_register_names | complete_reggroup_names)); } /* Perform completion on reggroup names. */ void reggroup_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { reg_or_group_completer_1 (tracker, text, word, complete_reggroup_names); } /* The default completer_handle_brkchars implementation. */ static void default_completer_handle_brkchars (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { set_rl_completer_word_break_characters (current_language->word_break_characters ()); } /* See definition in completer.h. */ completer_handle_brkchars_ftype * completer_handle_brkchars_func_for_completer (completer_ftype *fn) { if (fn == filename_completer) return filename_completer_handle_brkchars; if (fn == location_completer) return location_completer_handle_brkchars; if (fn == command_completer) return command_completer_handle_brkchars; return default_completer_handle_brkchars; } /* Used as brkchars when we want to tell readline we have a custom word point. We do that by making our rl_completion_word_break_hook set RL_POINT to the desired word point, and return the character at the word break point as the break char. This is two bytes in order to fit one break character plus the terminating null. */ static char gdb_custom_word_point_brkchars[2]; /* Since rl_basic_quote_characters is not completer-specific, we save its original value here, in order to be able to restore it in gdb_rl_attempted_completion_function. */ static const char *gdb_org_rl_basic_quote_characters = rl_basic_quote_characters; /* Get the list of chars that are considered as word breaks for the current command. */ static char * gdb_completion_word_break_characters_throw () { /* New completion starting. Get rid of the previous tracker and start afresh. */ delete current_completion.tracker; current_completion.tracker = new completion_tracker (true); completion_tracker &tracker = *current_completion.tracker; complete_line_internal (tracker, NULL, rl_line_buffer, rl_point, handle_brkchars); if (tracker.use_custom_word_point ()) { gdb_assert (tracker.custom_word_point () > 0); rl_point = tracker.custom_word_point () - 1; gdb_assert (rl_point >= 0 && rl_point < strlen (rl_line_buffer)); gdb_custom_word_point_brkchars[0] = rl_line_buffer[rl_point]; rl_completer_word_break_characters = gdb_custom_word_point_brkchars; rl_completer_quote_characters = NULL; /* Clear this too, so that if we're completing a quoted string, readline doesn't consider the quote character a delimiter. If we didn't do this, readline would auto-complete {b 'fun} to {'b 'function()'}, i.e., add the terminating \', but, it wouldn't append the separator space either, which is not desirable. So instead we take care of appending the quote character to the LCD ourselves, in gdb_rl_attempted_completion_function. Since this global is not just completer-specific, we'll restore it back to the default in gdb_rl_attempted_completion_function. */ rl_basic_quote_characters = NULL; } return (char *) rl_completer_word_break_characters; } /* Get the list of chars that are considered as word breaks for the current command. This function does not throw any exceptions and is called from readline. See gdb_completion_word_break_characters_throw for details. */ static char * gdb_completion_word_break_characters () noexcept { /* New completion starting. */ current_completion.aborted = false; try { return gdb_completion_word_break_characters_throw (); } catch (const gdb_exception &ex) { /* Set this to that gdb_rl_attempted_completion_function knows to abort early. */ current_completion.aborted = true; } return NULL; } /* Find the bounds of the word in TEXT for completion purposes, and return a pointer to the end of the word. Calls the completion machinery for a handle_brkchars phase (using TRACKER) to figure out the right work break characters for the command in TEXT. QUOTE_CHAR, if non-null, is set to the opening quote character if we found an unclosed quoted substring, '\0' otherwise. */ static const char * completion_find_completion_word (completion_tracker &tracker, const char *text, int *quote_char) { size_t point = strlen (text); complete_line_internal (tracker, NULL, text, point, handle_brkchars); if (tracker.use_custom_word_point ()) { gdb_assert (tracker.custom_word_point () > 0); *quote_char = tracker.quote_char (); return text + tracker.custom_word_point (); } gdb_rl_completion_word_info info; info.word_break_characters = rl_completer_word_break_characters; info.quote_characters = rl_completer_quote_characters; info.basic_quote_characters = rl_basic_quote_characters; return gdb_rl_find_completion_word (&info, quote_char, NULL, text); } /* See completer.h. */ void completion_tracker::recompute_lcd_visitor (completion_hash_entry *entry) { if (!m_lowest_common_denominator_valid) { /* This is the first lowest common denominator that we are considering, just copy it in. */ strcpy (m_lowest_common_denominator, entry->get_lcd ()); m_lowest_common_denominator_unique = true; m_lowest_common_denominator_valid = true; } else { /* Find the common denominator between the currently-known lowest common denominator and NEW_MATCH_UP. That becomes the new lowest common denominator. */ size_t i; const char *new_match = entry->get_lcd (); for (i = 0; (new_match[i] != '\0' && new_match[i] == m_lowest_common_denominator[i]); i++) ; if (m_lowest_common_denominator[i] != new_match[i]) { m_lowest_common_denominator[i] = '\0'; m_lowest_common_denominator_unique = false; } } } /* See completer.h. */ void completion_tracker::recompute_lowest_common_denominator () { /* We've already done this. */ if (m_lowest_common_denominator_valid) return; /* Resize the storage to ensure we have enough space, the plus one gives us space for the trailing null terminator we will include. */ m_lowest_common_denominator = (char *) xrealloc (m_lowest_common_denominator, m_lowest_common_denominator_max_length + 1); /* Callback used to visit each entry in the m_entries_hash. */ auto visitor_func = [] (void **slot, void *info) -> int { completion_tracker *obj = (completion_tracker *) info; completion_hash_entry *entry = (completion_hash_entry *) *slot; obj->recompute_lcd_visitor (entry); return 1; }; htab_traverse (m_entries_hash.get (), visitor_func, this); m_lowest_common_denominator_valid = true; } /* See completer.h. */ void completion_tracker::advance_custom_word_point_by (int len) { m_custom_word_point += len; } /* Build a new C string that is a copy of LCD with the whitespace of ORIG/ORIG_LEN preserved. Say the user is completing a symbol name, with spaces, like: "foo ( i" and the resulting completion match is: "foo(int)" we want to end up with an input line like: "foo ( int)" ^^^^^^^ => text from LCD [1], whitespace from ORIG preserved. ^^ => new text from LCD [1] - We must take characters from the LCD instead of the original text, since some completions want to change upper/lowercase. E.g.: "handle sig<>" completes to: "handle SIG[QUIT|etc.]" */ static char * expand_preserving_ws (const char *orig, size_t orig_len, const char *lcd) { const char *p_orig = orig; const char *orig_end = orig + orig_len; const char *p_lcd = lcd; std::string res; while (p_orig < orig_end) { if (*p_orig == ' ') { while (p_orig < orig_end && *p_orig == ' ') res += *p_orig++; p_lcd = skip_spaces (p_lcd); } else { /* Take characters from the LCD instead of the original text, since some completions change upper/lowercase. E.g.: "handle sig<>" completes to: "handle SIG[QUIT|etc.]" */ res += *p_lcd; p_orig++; p_lcd++; } } while (*p_lcd != '\0') res += *p_lcd++; return xstrdup (res.c_str ()); } /* See completer.h. */ completion_result completion_tracker::build_completion_result (const char *text, int start, int end) { size_t element_count = htab_elements (m_entries_hash.get ()); if (element_count == 0) return {}; /* +1 for the LCD, and +1 for NULL termination. */ char **match_list = XNEWVEC (char *, 1 + element_count + 1); /* Build replacement word, based on the LCD. */ recompute_lowest_common_denominator (); match_list[0] = expand_preserving_ws (text, end - start, m_lowest_common_denominator); if (m_lowest_common_denominator_unique) { /* We don't rely on readline appending the quote char as delimiter as then readline wouldn't append the ' ' after the completion. */ char buf[2] = { (char) quote_char () }; match_list[0] = reconcat (match_list[0], match_list[0], buf, (char *) NULL); match_list[1] = NULL; /* If the tracker wants to, or we already have a space at the end of the match, tell readline to skip appending another. */ char *match = match_list[0]; bool completion_suppress_append = (suppress_append_ws () || (match[0] != '\0' && match[strlen (match) - 1] == ' ')); return completion_result (match_list, 1, completion_suppress_append); } else { /* State object used while building the completion list. */ struct list_builder { list_builder (char **ml) : match_list (ml), index (1) { /* Nothing. */ } /* The list we are filling. */ char **match_list; /* The next index in the list to write to. */ int index; }; list_builder builder (match_list); /* Visit each entry in m_entries_hash and add it to the completion list, updating the builder state object. */ auto func = [] (void **slot, void *info) -> int { completion_hash_entry *entry = (completion_hash_entry *) *slot; list_builder *state = (list_builder *) info; state->match_list[state->index] = entry->release_name (); state->index++; return 1; }; /* Build the completion list and add a null at the end. */ htab_traverse_noresize (m_entries_hash.get (), func, &builder); match_list[builder.index] = NULL; return completion_result (match_list, builder.index - 1, false); } } /* See completer.h */ completion_result::completion_result () : match_list (NULL), number_matches (0), completion_suppress_append (false) {} /* See completer.h */ completion_result::completion_result (char **match_list_, size_t number_matches_, bool completion_suppress_append_) : match_list (match_list_), number_matches (number_matches_), completion_suppress_append (completion_suppress_append_) {} /* See completer.h */ completion_result::~completion_result () { reset_match_list (); } /* See completer.h */ completion_result::completion_result (completion_result &&rhs) noexcept : match_list (rhs.match_list), number_matches (rhs.number_matches) { rhs.match_list = NULL; rhs.number_matches = 0; } /* See completer.h */ char ** completion_result::release_match_list () { char **ret = match_list; match_list = NULL; return ret; } /* See completer.h */ void completion_result::sort_match_list () { if (number_matches > 1) { /* Element 0 is special (it's the common prefix), leave it be. */ std::sort (&match_list[1], &match_list[number_matches + 1], compare_cstrings); } } /* See completer.h */ void completion_result::reset_match_list () { if (match_list != NULL) { for (char **p = match_list; *p != NULL; p++) xfree (*p); xfree (match_list); match_list = NULL; } } /* Helper for gdb_rl_attempted_completion_function, which does most of the work. This is called by readline to build the match list array and to determine the lowest common denominator. The real matches list starts at match[1], while match[0] is the slot holding readline's idea of the lowest common denominator of all matches, which is what readline replaces the completion "word" with. TEXT is the caller's idea of the "word" we are looking at, as computed in the handle_brkchars phase. START is the offset from RL_LINE_BUFFER where TEXT starts. END is the offset from RL_LINE_BUFFER where TEXT ends (i.e., where rl_point is). You should thus pretend that the line ends at END (relative to RL_LINE_BUFFER). RL_LINE_BUFFER contains the entire text of the line. RL_POINT is the offset in that line of the cursor. You should pretend that the line ends at POINT. Returns NULL if there are no completions. */ static char ** gdb_rl_attempted_completion_function_throw (const char *text, int start, int end) { /* Completers that provide a custom word point in the handle_brkchars phase also compute their completions then. Completers that leave the completion word handling to readline must be called twice. If rl_point (i.e., END) is at column 0, then readline skips the handle_brkchars phase, and so we create a tracker now in that case too. */ if (end == 0 || !current_completion.tracker->use_custom_word_point ()) { delete current_completion.tracker; current_completion.tracker = new completion_tracker (true); complete_line (*current_completion.tracker, text, rl_line_buffer, rl_point); } completion_tracker &tracker = *current_completion.tracker; completion_result result = tracker.build_completion_result (text, start, end); rl_completion_suppress_append = result.completion_suppress_append; return result.release_match_list (); } /* Function installed as "rl_attempted_completion_function" readline hook. Wrapper around gdb_rl_attempted_completion_function_throw that catches C++ exceptions, which can't cross readline. */ static char ** gdb_rl_attempted_completion_function (const char *text, int start, int end) { /* Restore globals that might have been tweaked in gdb_completion_word_break_characters. */ rl_basic_quote_characters = gdb_org_rl_basic_quote_characters; /* If we end up returning NULL, either on error, or simple because there are no matches, inhibit readline's default filename completer. */ rl_attempted_completion_over = 1; /* If the handle_brkchars phase was aborted, don't try completing. */ if (current_completion.aborted) return NULL; try { return gdb_rl_attempted_completion_function_throw (text, start, end); } catch (const gdb_exception &ex) { } return NULL; } /* Return a message indicating that the maximum number of completions has been reached and that there may be more. */ const char * get_max_completions_reached_message (void) { return _("*** List may be truncated, max-completions reached. ***"); } /* GDB replacement for rl_display_match_list. Readline doesn't provide a clean interface for TUI(curses). A hack previously used was to send readline's rl_outstream through a pipe and read it from the event loop. Bleah. IWBN if readline abstracted away all the necessary bits, and this is what this code does. It replicates the parts of readline we need and then adds an abstraction layer, currently implemented as struct match_list_displayer, so that both CLI and TUI can use it. We copy all this readline code to minimize GDB-specific mods to readline. Once this code performs as desired then we can submit it to the readline maintainers. N.B. A lot of the code is the way it is in order to minimize differences from readline's copy. */ /* Not supported here. */ #undef VISIBLE_STATS #if defined (HANDLE_MULTIBYTE) #define MB_INVALIDCH(x) ((x) == (size_t)-1 || (x) == (size_t)-2) #define MB_NULLWCH(x) ((x) == 0) #endif #define ELLIPSIS_LEN 3 /* gdb version of readline/complete.c:get_y_or_n. 'y' -> returns 1, and 'n' -> returns 0. Also supported: space == 'y', RUBOUT == 'n', ctrl-g == start over. If FOR_PAGER is non-zero, then also supported are: NEWLINE or RETURN -> returns 2, and 'q' -> returns 0. */ static int gdb_get_y_or_n (int for_pager, const struct match_list_displayer *displayer) { int c; for (;;) { RL_SETSTATE (RL_STATE_MOREINPUT); c = displayer->read_key (displayer); RL_UNSETSTATE (RL_STATE_MOREINPUT); if (c == 'y' || c == 'Y' || c == ' ') return 1; if (c == 'n' || c == 'N' || c == RUBOUT) return 0; if (c == ABORT_CHAR || c < 0) { /* Readline doesn't erase_entire_line here, but without it the --More-- prompt isn't erased and neither is the text entered thus far redisplayed. */ displayer->erase_entire_line (displayer); /* Note: The arguments to rl_abort are ignored. */ rl_abort (0, 0); } if (for_pager && (c == NEWLINE || c == RETURN)) return 2; if (for_pager && (c == 'q' || c == 'Q')) return 0; displayer->beep (displayer); } } /* Pager function for tab-completion. This is based on readline/complete.c:_rl_internal_pager. LINES is the number of lines of output displayed thus far. Returns: -1 -> user pressed 'n' or equivalent, 0 -> user pressed 'y' or equivalent, N -> user pressed NEWLINE or equivalent and N is LINES - 1. */ static int gdb_display_match_list_pager (int lines, const struct match_list_displayer *displayer) { int i; displayer->puts (displayer, "--More--"); displayer->flush (displayer); i = gdb_get_y_or_n (1, displayer); displayer->erase_entire_line (displayer); if (i == 0) return -1; else if (i == 2) return (lines - 1); else return 0; } /* Return non-zero if FILENAME is a directory. Based on readline/complete.c:path_isdir. */ static int gdb_path_isdir (const char *filename) { struct stat finfo; return (stat (filename, &finfo) == 0 && S_ISDIR (finfo.st_mode)); } /* Return the portion of PATHNAME that should be output when listing possible completions. If we are hacking filename completion, we are only interested in the basename, the portion following the final slash. Otherwise, we return what we were passed. Since printing empty strings is not very informative, if we're doing filename completion, and the basename is the empty string, we look for the previous slash and return the portion following that. If there's no previous slash, we just return what we were passed. Based on readline/complete.c:printable_part. */ static char * gdb_printable_part (char *pathname) { char *temp, *x; if (rl_filename_completion_desired == 0) /* don't need to do anything */ return (pathname); temp = strrchr (pathname, '/'); #if defined (__MSDOS__) if (temp == 0 && ISALPHA ((unsigned char)pathname[0]) && pathname[1] == ':') temp = pathname + 1; #endif if (temp == 0 || *temp == '\0') return (pathname); /* If the basename is NULL, we might have a pathname like '/usr/src/'. Look for a previous slash and, if one is found, return the portion following that slash. If there's no previous slash, just return the pathname we were passed. */ else if (temp[1] == '\0') { for (x = temp - 1; x > pathname; x--) if (*x == '/') break; return ((*x == '/') ? x + 1 : pathname); } else return ++temp; } /* Compute width of STRING when displayed on screen by print_filename. Based on readline/complete.c:fnwidth. */ static int gdb_fnwidth (const char *string) { int width, pos; #if defined (HANDLE_MULTIBYTE) mbstate_t ps; int left, w; size_t clen; wchar_t wc; left = strlen (string) + 1; memset (&ps, 0, sizeof (mbstate_t)); #endif width = pos = 0; while (string[pos]) { if (CTRL_CHAR (string[pos]) || string[pos] == RUBOUT) { width += 2; pos++; } else { #if defined (HANDLE_MULTIBYTE) clen = mbrtowc (&wc, string + pos, left - pos, &ps); if (MB_INVALIDCH (clen)) { width++; pos++; memset (&ps, 0, sizeof (mbstate_t)); } else if (MB_NULLWCH (clen)) break; else { pos += clen; w = wcwidth (wc); width += (w >= 0) ? w : 1; } #else width++; pos++; #endif } } return width; } /* Print TO_PRINT, one matching completion. PREFIX_BYTES is number of common prefix bytes. Based on readline/complete.c:fnprint. */ static int gdb_fnprint (const char *to_print, int prefix_bytes, const struct match_list_displayer *displayer) { int printed_len, w; const char *s; #if defined (HANDLE_MULTIBYTE) mbstate_t ps; const char *end; size_t tlen; int width; wchar_t wc; end = to_print + strlen (to_print) + 1; memset (&ps, 0, sizeof (mbstate_t)); #endif printed_len = 0; /* Don't print only the ellipsis if the common prefix is one of the possible completions */ if (to_print[prefix_bytes] == '\0') prefix_bytes = 0; if (prefix_bytes) { char ellipsis; ellipsis = (to_print[prefix_bytes] == '.') ? '_' : '.'; for (w = 0; w < ELLIPSIS_LEN; w++) displayer->putch (displayer, ellipsis); printed_len = ELLIPSIS_LEN; } s = to_print + prefix_bytes; while (*s) { if (CTRL_CHAR (*s)) { displayer->putch (displayer, '^'); displayer->putch (displayer, UNCTRL (*s)); printed_len += 2; s++; #if defined (HANDLE_MULTIBYTE) memset (&ps, 0, sizeof (mbstate_t)); #endif } else if (*s == RUBOUT) { displayer->putch (displayer, '^'); displayer->putch (displayer, '?'); printed_len += 2; s++; #if defined (HANDLE_MULTIBYTE) memset (&ps, 0, sizeof (mbstate_t)); #endif } else { #if defined (HANDLE_MULTIBYTE) tlen = mbrtowc (&wc, s, end - s, &ps); if (MB_INVALIDCH (tlen)) { tlen = 1; width = 1; memset (&ps, 0, sizeof (mbstate_t)); } else if (MB_NULLWCH (tlen)) break; else { w = wcwidth (wc); width = (w >= 0) ? w : 1; } for (w = 0; w < tlen; ++w) displayer->putch (displayer, s[w]); s += tlen; printed_len += width; #else displayer->putch (displayer, *s); s++; printed_len++; #endif } } return printed_len; } /* Output TO_PRINT to rl_outstream. If VISIBLE_STATS is defined and we are using it, check for and output a single character for `special' filenames. Return the number of characters we output. Based on readline/complete.c:print_filename. */ static int gdb_print_filename (char *to_print, char *full_pathname, int prefix_bytes, const struct match_list_displayer *displayer) { int printed_len, extension_char, slen, tlen; char *s, c, *new_full_pathname; const char *dn; extern int _rl_complete_mark_directories; extension_char = 0; printed_len = gdb_fnprint (to_print, prefix_bytes, displayer); #if defined (VISIBLE_STATS) if (rl_filename_completion_desired && (rl_visible_stats || _rl_complete_mark_directories)) #else if (rl_filename_completion_desired && _rl_complete_mark_directories) #endif { /* If to_print != full_pathname, to_print is the basename of the path passed. In this case, we try to expand the directory name before checking for the stat character. */ if (to_print != full_pathname) { /* Terminate the directory name. */ c = to_print[-1]; to_print[-1] = '\0'; /* If setting the last slash in full_pathname to a NUL results in full_pathname being the empty string, we are trying to complete files in the root directory. If we pass a null string to the bash directory completion hook, for example, it will expand it to the current directory. We just want the `/'. */ if (full_pathname == 0 || *full_pathname == 0) dn = "/"; else if (full_pathname[0] != '/') dn = full_pathname; else if (full_pathname[1] == 0) dn = "//"; /* restore trailing slash to `//' */ else if (full_pathname[1] == '/' && full_pathname[2] == 0) dn = "/"; /* don't turn /// into // */ else dn = full_pathname; s = tilde_expand (dn); if (rl_directory_completion_hook) (*rl_directory_completion_hook) (&s); slen = strlen (s); tlen = strlen (to_print); new_full_pathname = (char *)xmalloc (slen + tlen + 2); strcpy (new_full_pathname, s); if (s[slen - 1] == '/') slen--; else new_full_pathname[slen] = '/'; new_full_pathname[slen] = '/'; strcpy (new_full_pathname + slen + 1, to_print); #if defined (VISIBLE_STATS) if (rl_visible_stats) extension_char = stat_char (new_full_pathname); else #endif if (gdb_path_isdir (new_full_pathname)) extension_char = '/'; xfree (new_full_pathname); to_print[-1] = c; } else { s = tilde_expand (full_pathname); #if defined (VISIBLE_STATS) if (rl_visible_stats) extension_char = stat_char (s); else #endif if (gdb_path_isdir (s)) extension_char = '/'; } xfree (s); if (extension_char) { displayer->putch (displayer, extension_char); printed_len++; } } return printed_len; } /* GDB version of readline/complete.c:complete_get_screenwidth. */ static int gdb_complete_get_screenwidth (const struct match_list_displayer *displayer) { /* Readline has other stuff here which it's not clear we need. */ return displayer->width; } extern int _rl_completion_prefix_display_length; extern int _rl_print_completions_horizontally; extern "C" int _rl_qsort_string_compare (const void *, const void *); typedef int QSFUNC (const void *, const void *); /* GDB version of readline/complete.c:rl_display_match_list. See gdb_display_match_list for a description of MATCHES, LEN, MAX. Returns non-zero if all matches are displayed. */ static int gdb_display_match_list_1 (char **matches, int len, int max, const struct match_list_displayer *displayer) { int count, limit, printed_len, lines, cols; int i, j, k, l, common_length, sind; char *temp, *t; int page_completions = displayer->height != INT_MAX && pagination_enabled; /* Find the length of the prefix common to all items: length as displayed characters (common_length) and as a byte index into the matches (sind) */ common_length = sind = 0; if (_rl_completion_prefix_display_length > 0) { t = gdb_printable_part (matches[0]); temp = strrchr (t, '/'); common_length = temp ? gdb_fnwidth (temp) : gdb_fnwidth (t); sind = temp ? strlen (temp) : strlen (t); if (common_length > _rl_completion_prefix_display_length && common_length > ELLIPSIS_LEN) max -= common_length - ELLIPSIS_LEN; else common_length = sind = 0; } /* How many items of MAX length can we fit in the screen window? */ cols = gdb_complete_get_screenwidth (displayer); max += 2; limit = cols / max; if (limit != 1 && (limit * max == cols)) limit--; /* If cols == 0, limit will end up -1 */ if (cols < displayer->width && limit < 0) limit = 1; /* Avoid a possible floating exception. If max > cols, limit will be 0 and a divide-by-zero fault will result. */ if (limit == 0) limit = 1; /* How many iterations of the printing loop? */ count = (len + (limit - 1)) / limit; /* Watch out for special case. If LEN is less than LIMIT, then just do the inner printing loop. 0 < len <= limit implies count = 1. */ /* Sort the items if they are not already sorted. */ if (rl_ignore_completion_duplicates == 0 && rl_sort_completion_matches) qsort (matches + 1, len, sizeof (char *), (QSFUNC *)_rl_qsort_string_compare); displayer->crlf (displayer); lines = 0; if (_rl_print_completions_horizontally == 0) { /* Print the sorted items, up-and-down alphabetically, like ls. */ for (i = 1; i <= count; i++) { for (j = 0, l = i; j < limit; j++) { if (l > len || matches[l] == 0) break; else { temp = gdb_printable_part (matches[l]); printed_len = gdb_print_filename (temp, matches[l], sind, displayer); if (j + 1 < limit) for (k = 0; k < max - printed_len; k++) displayer->putch (displayer, ' '); } l += count; } displayer->crlf (displayer); lines++; if (page_completions && lines >= (displayer->height - 1) && i < count) { lines = gdb_display_match_list_pager (lines, displayer); if (lines < 0) return 0; } } } else { /* Print the sorted items, across alphabetically, like ls -x. */ for (i = 1; matches[i]; i++) { temp = gdb_printable_part (matches[i]); printed_len = gdb_print_filename (temp, matches[i], sind, displayer); /* Have we reached the end of this line? */ if (matches[i+1]) { if (i && (limit > 1) && (i % limit) == 0) { displayer->crlf (displayer); lines++; if (page_completions && lines >= displayer->height - 1) { lines = gdb_display_match_list_pager (lines, displayer); if (lines < 0) return 0; } } else for (k = 0; k < max - printed_len; k++) displayer->putch (displayer, ' '); } } displayer->crlf (displayer); } return 1; } /* Utility for displaying completion list matches, used by both CLI and TUI. MATCHES is the list of strings, in argv format, LEN is the number of strings in MATCHES, and MAX is the length of the longest string in MATCHES. */ void gdb_display_match_list (char **matches, int len, int max, const struct match_list_displayer *displayer) { /* Readline will never call this if complete_line returned NULL. */ gdb_assert (max_completions != 0); /* complete_line will never return more than this. */ if (max_completions > 0) gdb_assert (len <= max_completions); if (rl_completion_query_items > 0 && len >= rl_completion_query_items) { char msg[100]; /* We can't use *query here because they wait for which is wrong here. This follows the readline version as closely as possible for compatibility's sake. See readline/complete.c. */ displayer->crlf (displayer); xsnprintf (msg, sizeof (msg), "Display all %d possibilities? (y or n)", len); displayer->puts (displayer, msg); displayer->flush (displayer); if (gdb_get_y_or_n (0, displayer) == 0) { displayer->crlf (displayer); return; } } if (gdb_display_match_list_1 (matches, len, max, displayer)) { /* Note: MAX_COMPLETIONS may be -1 or zero, but LEN is always > 0. */ if (len == max_completions) { /* The maximum number of completions has been reached. Warn the user that there may be more. */ const char *message = get_max_completions_reached_message (); displayer->puts (displayer, message); displayer->crlf (displayer); } } } /* See completer.h. */ bool skip_over_slash_fmt (completion_tracker &tracker, const char **args) { const char *text = *args; if (text[0] == '/') { bool in_fmt; tracker.set_use_custom_word_point (true); if (text[1] == '\0') { /* The user tried to complete after typing just the '/' character of the /FMT string. Step the completer past the '/', but we don't offer any completions. */ in_fmt = true; ++text; } else { /* The user has typed some characters after the '/', we assume this is a complete /FMT string, first skip over it. */ text = skip_to_space (text); if (*text == '\0') { /* We're at the end of the input string. The user has typed '/FMT' and asked for a completion. Push an empty completion string, this will cause readline to insert a space so the user now has '/FMT '. */ in_fmt = true; tracker.add_completion (make_unique_xstrdup (text)); } else { /* The user has already typed things after the /FMT, skip the whitespace and return false. Whoever called this function should then try to complete what comes next. */ in_fmt = false; text = skip_spaces (text); } } tracker.advance_custom_word_point_by (text - *args); *args = text; return in_fmt; } return false; } void _initialize_completer (); void _initialize_completer () { /* Setup some readline completion globals. */ rl_completion_word_break_hook = gdb_completion_word_break_characters; rl_attempted_completion_function = gdb_rl_attempted_completion_function; set_rl_completer_word_break_characters (default_word_break_characters ()); add_setshow_zuinteger_unlimited_cmd ("max-completions", no_class, &max_completions, _("\ Set maximum number of completion candidates."), _("\ Show maximum number of completion candidates."), _("\ Use this to limit the number of candidates considered\n\ during completion. Specifying \"unlimited\" or -1\n\ disables limiting. Note that setting either no limit or\n\ a very large limit can make completion slow."), NULL, NULL, &setlist, &showlist); }