From ef0b411a110cd2602cb89c3fb237baf8beb28545 Mon Sep 17 00:00:00 2001 From: Gary Benson Date: Sat, 31 Jan 2015 15:07:22 -0800 Subject: Add max-completions parameter, and implement tab-completion limiting. This commit adds a new exception, MAX_COMPLETIONS_REACHED_ERROR, to be thrown whenever the completer has generated too many candidates to be useful. A new user-settable variable, "max_completions", is added to control this behaviour. A top-level completion limit is added to complete_line_internal, as the final check to ensure the user never sees too many completions. An additional limit is added to default_make_symbol_completion_list_break_on, to halt time-consuming symbol table expansions. gdb/ChangeLog: PR cli/9007 PR cli/11920 PR cli/15548 * cli/cli-cmds.c (complete_command): Notify user if max-completions reached. * common/common-exceptions.h (enum errors) : New value. * completer.h (get_max_completions_reached_message): New declaration. (max_completions): Likewise. (completion_tracker_t): New typedef. (new_completion_tracker): New declaration. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completion_enum): New enum. (maybe_add_completion): New declaration. (throw_max_completions_reached_error): Likewise. * completer.c (max_completions): New global variable. (new_completion_tracker): New function. (free_completion_tracker): Likewise. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completions): Likewise. (throw_max_completions_reached_error): Likewise. (complete_line): Remove duplicates and limit result to max_completions entries. (get_max_completions_reached_message): New function. (gdb_display_match_list): Handle max_completions. (_initialize_completer): New declaration and function. * symtab.c: Include completer.h. (completion_tracker): New static variable. (completion_list_add_name): Call maybe_add_completion. (default_make_symbol_completion_list_break_on_1): Renamed from default_make_symbol_completion_list_break_on. Maintain completion_tracker across calls to completion_list_add_name. (default_make_symbol_completion_list_break_on): New function. * top.c (init_main): Set rl_completion_display_matches_hook. * tui/tui-io.c: Include completer.h. (tui_old_rl_display_matches_hook): New static global. (tui_rl_display_match_list): Notify user if max-completions reached. (tui_setup_io): Save/restore rl_completion_display_matches_hook. * NEWS (New Options): Mention set/show max-completions. gdb/doc/ChangeLog: * gdb.texinfo (Command Completion): Document new "set/show max-completions" option. gdb/testsuite/ChangeLog: * gdb.base/completion.exp: Disable completion limiting for existing tests. Add new tests to check completion limiting. * gdb.linespec/ls-errs.exp: Disable completion limiting. --- gdb/completer.h | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) (limited to 'gdb/completer.h') diff --git a/gdb/completer.h b/gdb/completer.h index dbb1cfb..56e1a2b 100644 --- a/gdb/completer.h +++ b/gdb/completer.h @@ -66,6 +66,8 @@ struct match_list_displayer 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 VEC (char_ptr) *complete_line (const char *text, const char *line_buffer, int point); @@ -112,4 +114,68 @@ extern const char *skip_quoted_chars (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; + +/* Object to track how many unique completions have been generated. + Used to limit the size of generated completion lists. */ + +typedef htab_t completion_tracker_t; + +/* Create a new completion tracker. + The result is a hash table to track added completions, or NULL + if max_completions <= 0. If max_completions < 0, tracking is disabled. + If max_completions == 0, the max is indeed zero. */ + +extern completion_tracker_t new_completion_tracker (void); + +/* Make a cleanup to free a completion tracker, and reset its pointer + to NULL. */ + +extern struct cleanup *make_cleanup_free_completion_tracker + (completion_tracker_t *tracker_ptr); + +/* Return values for maybe_add_completion. */ + +enum maybe_add_completion_enum +{ + /* NAME has been recorded and max_completions has not been reached, + or completion tracking is disabled (max_completions < 0). */ + MAYBE_ADD_COMPLETION_OK, + + /* NAME has been recorded and max_completions has been reached + (thus the caller can stop searching). */ + MAYBE_ADD_COMPLETION_OK_MAX_REACHED, + + /* max-completions entries has been reached. + Whether NAME is a duplicate or not is not determined. */ + MAYBE_ADD_COMPLETION_MAX_REACHED, + + /* NAME has already been recorded. + Note that this is never returned if completion tracking is disabled + (max_completions < 0). */ + MAYBE_ADD_COMPLETION_DUPLICATE +}; + +/* Add the completion NAME to the list of generated completions if + it is not there already. + If max_completions is negative, nothing is done, not even watching + for duplicates, and MAYBE_ADD_COMPLETION_OK is always returned. + + If MAYBE_ADD_COMPLETION_MAX_REACHED is returned, callers are required to + record at least one more completion. The final list will be pruned to + max_completions, but recording at least one more than max_completions is + the signal to the completion machinery that too many completions were + found. */ + +extern enum maybe_add_completion_enum + maybe_add_completion (completion_tracker_t tracker, char *name); + +/* Wrapper to throw MAX_COMPLETIONS_REACHED_ERROR. */ + +extern void throw_max_completions_reached_error (void); + #endif /* defined (COMPLETER_H) */ -- cgit v1.1