Handle custom completion match prefix / LCD

A following patch will add support for wild matching for C++ symbols,
making completing on "b push_ba" on a C++ program complete to
std::vector<...>::push_back, std::string::push_back etc., like:

 (gdb) b push_ba[TAB]
 std::vector<...>::push_back(....)
 std::string<...>::push_back(....)

Currently, we compute the "lowest common denominator" between all
completion candidates (what the input line is adjusted to) as the
common prefix of all matches.  That's problematic with wild matching
as above, as then we'd end up with TAB changing the input line to
"b std::", losing the original input, like:

 (gdb) b push_ba[TAB]
 std::vector<...>::push_back(....)
 std::string<...>::push_back(....)
 (gdb) b std::

while obviously we'd want it to adjust itself to "b push_back(" instead:

 (gdb) b push_ba[TAB]
 std::vector<...>::push_back(....)
 std::string<...>::push_back(....)
 (gdb) b push_back(

This patch adds the core code necessary to support this, though
nothing really makes use of it yet in this patch.

gdb/ChangeLog:
2017-11-29  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (ada_lookup_name_info::matches): Change type of
	parameter from completion_match to completion_match_result.
	Adjust.
	(do_wild_match, do_full_match, ada_symbol_name_matches): Likewise.
	* completer.c (completion_tracker::maybe_add_completion): Add
	match_for_lcd parameter and use it.
	(completion_tracker::add_completion): Likewise.
	* completer.h (class completion_match_for_lcd): New class.
	(completion_match_result::match_for_lcd): New field.
	(completion_match_result::set_match): New method.
	(completion_tracker): Add comments.
	(completion_tracker::add_completion): Add match_for_lcd parameter.
	(completion_tracker::reset_completion_match_result): Reset
	match_for_lcd too.
	(completion_tracker::maybe_add_completion): Add match_for_lcd
	parameter.
	(completion_tracker::m_lowest_common_denominator_unique): Extend
	comments.
	* cp-support.c (cp_symbol_name_matches_1)
	(cp_fq_symbol_name_matches): Change type of parameter from
	completion_match to completion_match_result.  Adjust.
	* language.c (default_symbol_name_matcher): Change type of
	parameter from completion_match to completion_match_result.
	Adjust.
	* language.h (completion_match_for_lcd): Forward declare.
	(default_symbol_name_matcher): Change type of parameter from
	completion_match to completion_match_result.
	* symtab.c (compare_symbol_name): Adjust.
	(completion_list_add_name): Pass the match_for_lcd to the tracker.
	* symtab.h (ada_lookup_name_info::matches): Change type of
	parameter from completion_match to completion_match_result.
	(symbol_name_matcher_ftype): Likewise, and update comments.
This commit is contained in:
Pedro Alves 2017-11-29 19:33:23 +00:00
parent 4024cf2b8d
commit a207cff2da
9 changed files with 170 additions and 39 deletions

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@ -1,3 +1,38 @@
2017-11-29 Pedro Alves <palves@redhat.com>
* ada-lang.c (ada_lookup_name_info::matches): Change type of
parameter from completion_match to completion_match_result.
Adjust.
(do_wild_match, do_full_match, ada_symbol_name_matches): Likewise.
* completer.c (completion_tracker::maybe_add_completion): Add
match_for_lcd parameter and use it.
(completion_tracker::add_completion): Likewise.
* completer.h (class completion_match_for_lcd): New class.
(completion_match_result::match_for_lcd): New field.
(completion_match_result::set_match): New method.
(completion_tracker): Add comments.
(completion_tracker::add_completion): Add match_for_lcd parameter.
(completion_tracker::reset_completion_match_result): Reset
match_for_lcd too.
(completion_tracker::maybe_add_completion): Add match_for_lcd
parameter.
(completion_tracker::m_lowest_common_denominator_unique): Extend
comments.
* cp-support.c (cp_symbol_name_matches_1)
(cp_fq_symbol_name_matches): Change type of parameter from
completion_match to completion_match_result. Adjust.
* language.c (default_symbol_name_matcher): Change type of
parameter from completion_match to completion_match_result.
Adjust.
* language.h (completion_match_for_lcd): Forward declare.
(default_symbol_name_matcher): Change type of parameter from
completion_match to completion_match_result.
* symtab.c (compare_symbol_name): Adjust.
(completion_list_add_name): Pass the match_for_lcd to the tracker.
* symtab.h (ada_lookup_name_info::matches): Change type of
parameter from completion_match to completion_match_result.
(symbol_name_matcher_ftype): Likewise, and update comments.
2017-11-29 Pedro Alves <palves@redhat.com>
* linespec.c (minsym_found, add_minsym): Use msymbol_is_function.

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@ -6357,7 +6357,7 @@ bool
ada_lookup_name_info::matches
(const char *sym_name,
symbol_name_match_type match_type,
completion_match *comp_match) const
completion_match_result *comp_match_res) const
{
bool match = false;
const char *text = m_encoded_name.c_str ();
@ -6415,15 +6415,12 @@ ada_lookup_name_info::matches
if (!match)
return false;
if (comp_match != NULL)
if (comp_match_res != NULL)
{
std::string &match_str = comp_match->storage ();
std::string &match_str = comp_match_res->match.storage ();
if (!m_encoded_p)
{
match_str = ada_decode (sym_name);
comp_match->set_match (match_str.c_str ());
}
match_str = ada_decode (sym_name);
else
{
if (m_verbatim_p)
@ -6431,8 +6428,9 @@ ada_lookup_name_info::matches
else
match_str = sym_name;
comp_match->set_match (match_str.c_str ());
}
comp_match_res->set_match (match_str.c_str ());
}
return true;
@ -13925,7 +13923,7 @@ static const struct exp_descriptor ada_exp_descriptor = {
static bool
do_wild_match (const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match)
completion_match_result *comp_match_res)
{
return wild_match (symbol_search_name, ada_lookup_name (lookup_name));
}
@ -13935,7 +13933,7 @@ do_wild_match (const char *symbol_search_name,
static bool
do_full_match (const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match)
completion_match_result *comp_match_res)
{
return full_match (symbol_search_name, ada_lookup_name (lookup_name));
}
@ -14005,11 +14003,11 @@ ada_lookup_name_info::ada_lookup_name_info (const lookup_name_info &lookup_name)
static bool
ada_symbol_name_matches (const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match)
completion_match_result *comp_match_res)
{
return lookup_name.ada ().matches (symbol_search_name,
lookup_name.match_type (),
match);
comp_match_res);
}
/* Implement the "la_get_symbol_name_matcher" language_defn method for

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@ -1502,7 +1502,9 @@ completion_tracker::~completion_tracker ()
/* See completer.h. */
bool
completion_tracker::maybe_add_completion (gdb::unique_xmalloc_ptr<char> name)
completion_tracker::maybe_add_completion
(gdb::unique_xmalloc_ptr<char> name,
completion_match_for_lcd *match_for_lcd)
{
void **slot;
@ -1515,7 +1517,13 @@ completion_tracker::maybe_add_completion (gdb::unique_xmalloc_ptr<char> name)
slot = htab_find_slot (m_entries_hash, name.get (), INSERT);
if (*slot == HTAB_EMPTY_ENTRY)
{
const char *match_for_lcd_str = name.get ();
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 ();
recompute_lowest_common_denominator (match_for_lcd_str);
@ -1529,9 +1537,10 @@ completion_tracker::maybe_add_completion (gdb::unique_xmalloc_ptr<char> name)
/* See completer.h. */
void
completion_tracker::add_completion (gdb::unique_xmalloc_ptr<char> name)
completion_tracker::add_completion (gdb::unique_xmalloc_ptr<char> name,
completion_match_for_lcd *match_for_lcd)
{
if (!maybe_add_completion (std::move (name)))
if (!maybe_add_completion (std::move (name), match_for_lcd))
throw_error (MAX_COMPLETIONS_REACHED_ERROR, _("Max completions reached."));
}

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@ -116,12 +116,56 @@ private:
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. */
class completion_match_for_lcd
{
public:
/* Set the match for LCD. See m_match's description. */
void set_match (const char *match)
{ m_match = match; }
/* Get the resulting LCD, after a successful match. */
const char *finish ()
{ return m_match; }
/* Prepare for another completion matching sequence. */
void clear ()
{ m_match = NULL; }
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;
};
/* 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
@ -188,6 +232,21 @@ public:
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.,
@ -205,7 +264,8 @@ public:
/* 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);
void add_completion (gdb::unique_xmalloc_ptr<char> name,
completion_match_for_lcd *match_for_lcd = NULL);
/* Add all completions matches in LIST. Elements are moved out of
LIST. */
@ -268,6 +328,7 @@ public:
/* Clear any previous match. */
res.match.clear ();
res.match_for_lcd.clear ();
return m_completion_match_result;
}
@ -290,10 +351,19 @@ private:
/* 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);
bool maybe_add_completion (gdb::unique_xmalloc_ptr<char> name,
completion_match_for_lcd *match_for_lcd);
/* Given a new match, recompute the lowest common denominator (LCD)
to hand over to readline. */
to hand over to readline. Normally readline computes this itself
based on the whole set of completion matches. However, some
completers want to override readline, in order to be able to
provide a LCD that is not really a prefix of the matches, but the
lowest common denominator of some relevant substring of each
match. E.g., "b push_ba" completes to
"std::vector<..>::push_back", "std::string::push_back", etc., and
in this case we want the lowest common denominator to be
"push_back" instead of "std::". */
void recompute_lowest_common_denominator (const char *new_match);
/* Completion match outputs returned by the symbol name matching
@ -348,8 +418,13 @@ private:
See intro. */
char *m_lowest_common_denominator = NULL;
/* If true, the LCD is unique. I.e., all completion candidates had
the same string. */
/* 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;
};

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@ -1634,14 +1634,14 @@ cp_symbol_name_matches_1 (const char *symbol_search_name,
const char *lookup_name,
size_t lookup_name_len,
strncmp_iw_mode mode,
completion_match *match)
completion_match_result *comp_match_res)
{
if (strncmp_iw_with_mode (symbol_search_name,
lookup_name, lookup_name_len,
mode, language_cplus) == 0)
{
if (match != NULL)
match->set_match (symbol_search_name);
if (comp_match_res != NULL)
comp_match_res->set_match (symbol_search_name);
return true;
}
@ -1653,7 +1653,7 @@ cp_symbol_name_matches_1 (const char *symbol_search_name,
static bool
cp_fq_symbol_name_matches (const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match)
completion_match_result *comp_match_res)
{
/* Get the demangled name. */
const std::string &name = lookup_name.cplus ().lookup_name ();
@ -1664,7 +1664,7 @@ cp_fq_symbol_name_matches (const char *symbol_search_name,
return cp_symbol_name_matches_1 (symbol_search_name,
name.c_str (), name.size (),
mode, match);
mode, comp_match_res);
}
/* See cp-support.h. */

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@ -704,7 +704,7 @@ default_get_string (struct value *value, gdb_byte **buffer, int *length,
bool
default_symbol_name_matcher (const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match)
completion_match_result *comp_match_res)
{
const std::string &name = lookup_name.name ();
@ -715,8 +715,8 @@ default_symbol_name_matcher (const char *symbol_search_name,
if (strncmp_iw_with_mode (symbol_search_name, name.c_str (), name.size (),
mode, language_minimal) == 0)
{
if (match != NULL)
match->set_match (symbol_search_name);
if (comp_match_res != NULL)
comp_match_res->set_match (symbol_search_name);
return true;
}
else

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@ -37,6 +37,7 @@ struct type_print_options;
struct lang_varobj_ops;
struct parser_state;
struct compile_instance;
struct completion_match_for_lcd;
#define MAX_FORTRAN_DIMS 7 /* Maximum number of F77 array dims. */
@ -629,7 +630,7 @@ void c_get_string (struct value *value, gdb_byte **buffer, int *length,
extern bool default_symbol_name_matcher
(const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match);
completion_match_result *comp_match_res);
/* Get LANG's symbol_name_matcher method for LOOKUP_NAME. Returns
default_symbol_name_matcher if not set. */

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@ -4698,7 +4698,7 @@ compare_symbol_name (const char *symbol_name, language symbol_language,
symbol_name_matcher_ftype *name_match
= language_get_symbol_name_matcher (lang, lookup_name);
return name_match (symbol_name, lookup_name, &match_res.match);
return name_match (symbol_name, lookup_name, &match_res);
}
/* See symtab.h. */
@ -4751,7 +4751,14 @@ completion_list_add_name (completion_tracker &tracker,
gdb::unique_xmalloc_ptr<char> completion (newobj);
tracker.add_completion (std::move (completion));
/* Here we pass the match-for-lcd object to add_completion. Some
languages match the user text against substrings of symbol
names in some cases. E.g., in C++, "b push_ba" completes to
"std::vector::push_back", "std::string::push_back", etc., and
in this case we want the completion lowest common denominator
to be "push_back" instead of "std::". */
tracker.add_completion (std::move (completion),
&match_res.match_for_lcd);
}
}

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@ -84,7 +84,7 @@ class ada_lookup_name_info final
otherwise. If non-NULL, store the matching results in MATCH. */
bool matches (const char *symbol_search_name,
symbol_name_match_type match_type,
completion_match *match) const;
completion_match_result *comp_match_res) const;
/* The Ada-encoded lookup name. */
const std::string &lookup_name () const
@ -295,15 +295,21 @@ private:
SYMBOL_SEARCH_NAME should be a symbol's "search" name.
On success and if non-NULL, MATCH is set to point to the symbol
name as should be presented to the user as a completion match list
element. In most languages, this is the same as the symbol's
search name, but in some, like Ada, the display name is dynamically
computed within the comparison routine. */
On success and if non-NULL, COMP_MATCH_RES->match is set to point
to the symbol name as should be presented to the user as a
completion match list element. In most languages, this is the same
as the symbol's search name, but in some, like Ada, the display
name is dynamically computed within the comparison routine.
Also, on success and if non-NULL, COMP_MATCH_RES->match_for_lcd
points the part of SYMBOL_SEARCH_NAME that was considered to match
LOOKUP_NAME. E.g., in C++, in linespec/wild mode, if the symbol is
"foo::function()" and LOOKUP_NAME is "function(", MATCH_FOR_LCD
points to "function()" inside SYMBOL_SEARCH_NAME. */
typedef bool (symbol_name_matcher_ftype)
(const char *symbol_search_name,
const lookup_name_info &lookup_name,
completion_match *match);
completion_match_result *comp_match_res);
/* Some of the structures in this file are space critical.
The space-critical structures are: