/* Header for GDB line completion. Copyright (C) 2000-2021 Free Software Foundation, Inc. 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 <http://www.gnu.org/licenses/>. */ #if !defined (COMPLETER_H) #define COMPLETER_H 1 #include "gdbsupport/gdb_vecs.h" #include "command.h" /* Types of functions in struct match_list_displayer. */ struct match_list_displayer; typedef void mld_crlf_ftype (const struct match_list_displayer *); typedef void mld_putch_ftype (const struct match_list_displayer *, int); typedef void mld_puts_ftype (const struct match_list_displayer *, const char *); typedef void mld_flush_ftype (const struct match_list_displayer *); typedef void mld_erase_entire_line_ftype (const struct match_list_displayer *); typedef void mld_beep_ftype (const struct match_list_displayer *); typedef int mld_read_key_ftype (const struct match_list_displayer *); /* Interface between CLI/TUI and gdb_match_list_displayer. */ struct match_list_displayer { /* The screen dimensions to work with when displaying matches. */ int height, width; /* Print cr,lf. */ mld_crlf_ftype *crlf; /* Not "putc" to avoid issues where it is a stdio macro. Sigh. */ mld_putch_ftype *putch; /* Print a string. */ mld_puts_ftype *puts; /* Flush all accumulated output. */ mld_flush_ftype *flush; /* Erase the currently line on the terminal (but don't discard any text the user has entered, readline may shortly re-print it). */ mld_erase_entire_line_ftype *erase_entire_line; /* Ring the bell. */ mld_beep_ftype *beep; /* Read one key. */ mld_read_key_ftype *read_key; }; /* A list of completion candidates. Each element is a malloc string, because ownership of the strings is transferred to readline, which calls free on each element. */ typedef std::vector<gdb::unique_xmalloc_ptr<char>> completion_list; /* The result of a successful completion match. When doing symbol comparison, we use the symbol search name for the symbol name match check, but the matched name that is shown to the user may be different. For example, Ada uses encoded names for lookup, but then wants to decode the symbol name to show to the user, and also in some cases wrap the matched name in "<sym>" (meaning we can't always use the symbol's print name). */ class completion_match { public: /* Get the completion match result. See m_match/m_storage's descriptions. */ const char *match () { return m_match; } /* Set the completion match result. See m_match/m_storage's descriptions. */ void set_match (const char *match) { m_match = match; } /* Get temporary storage for generating a match result, dynamically. The built string is only good until the next clear() call. I.e., good until the next symbol comparison. */ std::string &storage () { return m_storage; } /* Prepare for another completion matching sequence. */ void clear () { m_match = NULL; m_storage.clear (); } private: /* The completion match result. This can either be a pointer into M_STORAGE string, or it can be a pointer into the some other string that outlives the completion matching sequence (usually, a pointer to a symbol's name). */ const char *m_match; /* Storage a symbol comparison routine can use for generating a match result, dynamically. The built string is only good until the next clear() call. I.e., good until the next symbol comparison. */ std::string m_storage; }; /* The result of a successful completion match, but for least common denominator (LCD) computation. Some completers provide matches that don't start with the completion "word". E.g., completing on "b push_ba" on a C++ program usually completes to std::vector<...>::push_back, std::string::push_back etc. In such case, the symbol comparison routine will set the LCD match to point into the "push_back" substring within the symbol's name string. Also, in some cases, the symbol comparison routine will want to ignore parts of the symbol name for LCD purposes, such as for example symbols with abi tags in C++. In such cases, the symbol comparison routine will set MARK_IGNORED_RANGE to mark the ignored substrings of the matched string. The resulting LCD string with the ignored parts stripped out is computed at the end of a completion match sequence iff we had a positive match. */ class completion_match_for_lcd { public: /* Get the resulting LCD, after a successful match. */ const char *match () { return m_match; } /* Set the match for LCD. See m_match's description. */ void set_match (const char *match) { m_match = match; } /* Mark the range between [BEGIN, END) as ignored. */ void mark_ignored_range (const char *begin, const char *end) { m_ignored_ranges.emplace_back (begin, end); } /* Get the resulting LCD, after a successful match. If there are ignored ranges, then this builds a new string with the ignored parts removed (and stores it internally). As such, the result of this call is only good for the current completion match sequence. */ const char *finish () { if (m_ignored_ranges.empty ()) return m_match; else { m_finished_storage.clear (); const char *prev = m_match; for (const auto &range : m_ignored_ranges) { m_finished_storage.append (prev, range.first); prev = range.second; } m_finished_storage.append (prev); return m_finished_storage.c_str (); } } /* Prepare for another completion matching sequence. */ void clear () { m_match = NULL; m_ignored_ranges.clear (); } private: /* The completion match result for LCD. This is usually either a pointer into to a substring within a symbol's name, or to the storage of the pairing completion_match object. */ const char *m_match; /* The ignored substring ranges within M_MATCH. E.g., if we were looking for completion matches for C++ functions starting with "functio" and successfully match: "function[abi:cxx11](int)" the ignored ranges vector will contain an entry that delimits the "[abi:cxx11]" substring, such that calling finish() results in: "function(int)" */ std::vector<std::pair<const char *, const char *>> m_ignored_ranges; /* Storage used by the finish() method, if it has to compute a new string. */ std::string m_finished_storage; }; /* Convenience aggregate holding info returned by the symbol name matching routines (see symbol_name_matcher_ftype). */ struct completion_match_result { /* The completion match candidate. */ completion_match match; /* The completion match, for LCD computation purposes. */ completion_match_for_lcd match_for_lcd; /* Convenience that sets both MATCH and MATCH_FOR_LCD. M_FOR_LCD is optional. If not specified, defaults to M. */ void set_match (const char *m, const char *m_for_lcd = NULL) { match.set_match (m); if (m_for_lcd == NULL) match_for_lcd.set_match (m); else match_for_lcd.set_match (m_for_lcd); } }; /* The final result of a completion that is handed over to either readline or the "completion" command (which pretends to be readline). Mainly a wrapper for a readline-style match list array, though other bits of info are included too. */ struct completion_result { /* Create an empty result. */ completion_result (); /* Create a result. */ completion_result (char **match_list, size_t number_matches, bool completion_suppress_append); /* Destroy a result. */ ~completion_result (); DISABLE_COPY_AND_ASSIGN (completion_result); /* Move a result. */ completion_result (completion_result &&rhs) noexcept; /* Release ownership of the match list array. */ char **release_match_list (); /* Sort the match list. */ void sort_match_list (); private: /* Destroy the match list array and its contents. */ void reset_match_list (); public: /* (There's no point in making these fields private, since the whole point of this wrapper is to build data in the layout expected by readline. Making them private would require adding getters for the "complete" command, which would expose the same implementation details anyway.) */ /* The match list array, in the format that readline expects. match_list[0] contains the common prefix. The real match list starts at index 1. The list is NULL terminated. If there's only one match, then match_list[1] is NULL. If there are no matches, then this is NULL. */ char **match_list; /* The number of matched completions in MATCH_LIST. Does not include the NULL terminator or the common prefix. */ size_t number_matches; /* Whether readline should suppress appending a whitespace, when there's only one possible completion. */ bool completion_suppress_append; }; /* Object used by completers to build a completion match list to hand over to readline. It tracks: - How many unique completions have been generated, to terminate completion list generation early if the list has grown to a size so large as to be useless. This helps avoid GDB seeming to lock up in the event the user requests to complete on something vague that necessitates the time consuming expansion of many symbol tables. - The completer's idea of least common denominator (aka the common prefix) between all completion matches to hand over to readline. Some completers provide matches that don't start with the completion "word". E.g., completing on "b push_ba" on a C++ program usually completes to std::vector<...>::push_back, std::string::push_back etc. If all matches happen to start with "std::", then readline would figure out that the lowest common denominator is "std::", and thus would do a partial completion with that. I.e., it would replace "push_ba" in the input buffer with "std::", losing the original "push_ba", which is obviously undesirable. To avoid that, such completers pass the substring of the match that matters for common denominator computation as MATCH_FOR_LCD argument to add_completion. The end result is passed to readline in gdb_rl_attempted_completion_function. - The custom word point to hand over to readline, for completers that parse the input string in order to dynamically adjust themselves depending on exactly what they're completing. E.g., the linespec completer needs to bypass readline's too-simple word breaking algorithm. */ class completion_tracker { public: completion_tracker (); ~completion_tracker (); DISABLE_COPY_AND_ASSIGN (completion_tracker); /* Add the completion NAME to the list of generated completions if it is not there already. If too many completions were already found, this throws an error. */ void add_completion (gdb::unique_xmalloc_ptr<char> name, completion_match_for_lcd *match_for_lcd = NULL, const char *text = NULL, const char *word = NULL); /* Add all completions matches in LIST. Elements are moved out of LIST. */ void add_completions (completion_list &&list); /* Remove completion matching NAME from the completion list, does nothing if NAME is not already in the completion list. */ void remove_completion (const char *name); /* Set the quote char to be appended after a unique completion is added to the input line. Set to '\0' to clear. See m_quote_char's description. */ void set_quote_char (int quote_char) { m_quote_char = quote_char; } /* The quote char to be appended after a unique completion is added to the input line. Returns '\0' if no quote char has been set. See m_quote_char's description. */ int quote_char () { return m_quote_char; } /* Tell the tracker that the current completer wants to provide a custom word point instead of a list of a break chars, in the handle_brkchars phase. Such completers must also compute their completions then. */ void set_use_custom_word_point (bool enable) { m_use_custom_word_point = enable; } /* Whether the current completer computes a custom word point. */ bool use_custom_word_point () const { return m_use_custom_word_point; } /* The custom word point. */ int custom_word_point () const { return m_custom_word_point; } /* Set the custom word point to POINT. */ void set_custom_word_point (int point) { m_custom_word_point = point; } /* Advance the custom word point by LEN. */ void advance_custom_word_point_by (int len); /* Whether to tell readline to skip appending a whitespace after the completion. See m_suppress_append_ws. */ bool suppress_append_ws () const { return m_suppress_append_ws; } /* Set whether to tell readline to skip appending a whitespace after the completion. See m_suppress_append_ws. */ void set_suppress_append_ws (bool suppress) { m_suppress_append_ws = suppress; } /* Return true if we only have one completion, and it matches exactly the completion word. I.e., completing results in what we already have. */ bool completes_to_completion_word (const char *word); /* Get a reference to the shared (between all the multiple symbol name comparison calls) completion_match_result object, ready for another symbol name match sequence. */ completion_match_result &reset_completion_match_result () { completion_match_result &res = m_completion_match_result; /* Clear any previous match. */ res.match.clear (); res.match_for_lcd.clear (); return m_completion_match_result; } /* True if we have any completion match recorded. */ bool have_completions () const { return htab_elements (m_entries_hash.get ()) > 0; } /* Discard the current completion match list and the current LCD. */ void discard_completions (); /* Build a completion_result containing the list of completion matches to hand over to readline. The parameters are as in rl_attempted_completion_function. */ completion_result build_completion_result (const char *text, int start, int end); private: /* The type that we place into the m_entries_hash hash table. */ class completion_hash_entry; /* Add the completion NAME to the list of generated completions if it is not there already. If false is returned, too many completions were found. */ bool maybe_add_completion (gdb::unique_xmalloc_ptr<char> name, completion_match_for_lcd *match_for_lcd, const char *text, const char *word); /* Ensure that the lowest common denominator held in the member variable M_LOWEST_COMMON_DENOMINATOR is valid. This method must be called if there is any chance that new completions have been added to the tracker before the lowest common denominator is read. */ void recompute_lowest_common_denominator (); /* Callback used from recompute_lowest_common_denominator, called for every entry in m_entries_hash. */ void recompute_lcd_visitor (completion_hash_entry *entry); /* Completion match outputs returned by the symbol name matching routines (see symbol_name_matcher_ftype). These results are only valid for a single match call. This is here in order to be able to conveniently share the same storage among all the calls to the symbol name matching routines. */ completion_match_result m_completion_match_result; /* The completion matches found so far, in a hash table, for duplicate elimination as entries are added. Otherwise the user is left scratching his/her head: readline and complete_command will remove duplicates, and if removal of duplicates there brings the total under max_completions the user may think gdb quit searching too early. */ htab_up m_entries_hash; /* If non-zero, then this is the quote char that needs to be appended after completion (iff we have a unique completion). We don't rely on readline appending the quote char as delimiter as then readline wouldn't append the ' ' after the completion. I.e., we want this: before tab: "b 'function(" after tab: "b 'function()' " */ int m_quote_char = '\0'; /* If true, the completer has its own idea of "word" point, and doesn't want to rely on readline computing it based on brkchars. Set in the handle_brkchars phase. */ bool m_use_custom_word_point = false; /* The completer's idea of where the "word" we were looking at is relative to RL_LINE_BUFFER. This is advanced in the handle_brkchars phase as the completer discovers potential completable words. */ int m_custom_word_point = 0; /* If true, tell readline to skip appending a whitespace after the completion. Automatically set if we have a unique completion that already has a space at the end. A completer may also explicitly set this. E.g., the linespec completer sets this when the completion ends with the ":" separator between filename and function name. */ bool m_suppress_append_ws = false; /* Our idea of lowest common denominator to hand over to readline. See intro. */ char *m_lowest_common_denominator = NULL; /* If true, the LCD is unique. I.e., all completions had the same MATCH_FOR_LCD substring, even if the completions were different. For example, if "break function<tab>" found "a::function()" and "b::function()", the LCD will be "function()" in both cases and so we want to tell readline to complete the line with "function()", instead of showing all the possible completions. */ bool m_lowest_common_denominator_unique = false; /* True if the value in M_LOWEST_COMMON_DENOMINATOR is correct. This is set to true each time RECOMPUTE_LOWEST_COMMON_DENOMINATOR is called, and reset to false whenever a new completion is added. */ bool m_lowest_common_denominator_valid = false; /* To avoid calls to xrealloc in RECOMPUTE_LOWEST_COMMON_DENOMINATOR, we track the maximum possible size of the lowest common denominator, which we know as each completion is added. */ size_t m_lowest_common_denominator_max_length = 0; }; /* Return a string to hand off to readline as a completion match candidate, potentially composed of parts of MATCH_NAME and of TEXT/WORD. For a description of TEXT/WORD see completer_ftype. */ extern gdb::unique_xmalloc_ptr<char> make_completion_match_str (const char *match_name, const char *text, const char *word); /* Like above, but takes ownership of MATCH_NAME (i.e., can reuse/return it). */ extern gdb::unique_xmalloc_ptr<char> make_completion_match_str (gdb::unique_xmalloc_ptr<char> &&match_name, const char *text, const char *word); extern void gdb_display_match_list (char **matches, int len, int max, const struct match_list_displayer *); extern const char *get_max_completions_reached_message (void); extern void complete_line (completion_tracker &tracker, const char *text, const char *line_buffer, int point); /* Complete LINE and return completion results. For completion purposes, cursor position is assumed to be at the end of LINE. WORD is set to the end of word to complete. QUOTE_CHAR is set to the opening quote character if we found an unclosed quoted substring, '\0' otherwise. */ extern completion_result complete (const char *line, char const **word, int *quote_char); /* 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. */ extern const char *completion_find_completion_word (completion_tracker &tracker, const char *text, int *quote_char); /* Assuming TEXT is an expression in the current language, find the completion word point for TEXT, emulating the algorithm readline uses to find the word point, using the current language's word break characters. */ const char *advance_to_expression_complete_word_point (completion_tracker &tracker, const char *text); /* Assuming TEXT is an filename, find the completion word point for TEXT, emulating the algorithm readline uses to find the word point. */ extern const char *advance_to_filename_complete_word_point (completion_tracker &tracker, const char *text); extern char **gdb_rl_attempted_completion_function (const char *text, int start, int end); extern void noop_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void filename_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void expression_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void location_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void symbol_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void command_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void signal_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void reg_or_group_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern void reggroup_completer (struct cmd_list_element *, completion_tracker &tracker, const char *, const char *); extern const char *get_gdb_completer_quote_characters (void); extern char *gdb_completion_word_break_characters (void); /* 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 *". */ extern void set_rl_completer_word_break_characters (const char *break_chars); /* Get the matching completer_handle_brkchars_ftype function for FN. FN is one of the core completer functions above (filename, location, symbol, etc.). This function is useful for cases when the completer doesn't know the type of the completion until some calculation is done (e.g., for Python functions). */ extern completer_handle_brkchars_ftype * completer_handle_brkchars_func_for_completer (completer_ftype *fn); /* Exported to linespec.c */ /* Return a list of all source files whose names begin with matching TEXT. */ extern completion_list complete_source_filenames (const char *text); /* Complete on expressions. Often this means completing on symbol names, but some language parsers also have support for completing field names. */ extern void complete_expression (completion_tracker &tracker, const char *text, const char *word); /* Called by custom word point completers that want to recurse into the completion machinery to complete a command. Used to complete COMMAND in "thread apply all COMMAND", for example. Note that unlike command_completer, this fully recurses into the proper completer for COMMAND, so that e.g., (gdb) thread apply all print -[TAB] does the right thing and show the print options. */ extern void complete_nested_command_line (completion_tracker &tracker, const char *text); extern const char *skip_quoted_chars (const char *, const char *, const char *); extern const char *skip_quoted (const char *); /* Maximum number of candidates to consider before the completer bails by throwing MAX_COMPLETIONS_REACHED_ERROR. Negative values disable limiting. */ extern int max_completions; #endif /* defined (COMPLETER_H) */