YouCompleteMe/cpp/ycm/ClangCompleter/ClangCompleter.cpp
Strahinja Val Markovic 8cc9c9ca76 Race condition fix; caused latency on first load
The issue was that the user could open a C-family file and have it start
compiling in the background. While it is still compiling, he could trigger the
completion system with a member dot operator. Because the file was still
compiling for the very first time, the TranslationUnit object was yet not
created. Sadly, this meant that UpdatingTranslationUnit would return false, and
a new query request would be created, the GUI would hang until it was done
aaaaand terrible lag until the file was compiled.

This was a very rare edge case that could also only be triggered if it takes a
considerable amount of time to compile the file.
2013-01-24 18:37:44 -08:00

520 lines
16 KiB
C++

// Copyright (C) 2011, 2012 Strahinja Val Markovic <val@markovic.io>
//
// This file is part of YouCompleteMe.
//
// YouCompleteMe 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.
//
// YouCompleteMe 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 YouCompleteMe. If not, see <http://www.gnu.org/licenses/>.
#include "ClangCompleter.h"
#include "exceptions.h"
#include "Result.h"
#include "Candidate.h"
#include "TranslationUnit.h"
#include "standard.h"
#include "CandidateRepository.h"
#include "CompletionData.h"
#include "ConcurrentLatestValue.h"
#include "Utils.h"
#include "ClangUtils.h"
#include <clang-c/Index.h>
#include <boost/make_shared.hpp>
using boost::bind;
using boost::cref;
using boost::function;
using boost::lock_guard;
using boost::make_shared;
using boost::mutex;
using boost::packaged_task;
using boost::ref;
using boost::shared_lock;
using boost::shared_mutex;
using boost::shared_ptr;
using boost::thread;
using boost::thread_interrupted;
using boost::try_to_lock_t;
using boost::unique_future;
using boost::unique_lock;
using boost::unordered_map;
namespace YouCompleteMe {
extern const unsigned int MAX_ASYNC_THREADS;
extern const unsigned int MIN_ASYNC_THREADS;
namespace {
struct CompletionDataAndResult {
CompletionDataAndResult( const CompletionData *completion_data,
const Result &result )
: completion_data_( completion_data ), result_( result ) {}
bool operator< ( const CompletionDataAndResult &other ) const {
return result_ < other.result_;
}
const CompletionData *completion_data_;
Result result_;
};
} // unnamed namespace
ClangCompleter::ClangCompleter()
: candidate_repository_( CandidateRepository::Instance() ),
threading_enabled_( false ),
time_to_die_( false ),
clang_data_ready_( false ) {
clang_index_ = clang_createIndex( 0, 0 );
}
ClangCompleter::~ClangCompleter() {
// We need to clear this before calling clang_disposeIndex because the
// translation units need to be destroyed before the index is destroyed.
filename_to_translation_unit_.clear();
clang_disposeIndex( clang_index_ );
{
unique_lock< shared_mutex > lock( time_to_die_mutex_ );
time_to_die_ = true;
}
sorting_threads_.interrupt_all();
sorting_threads_.join_all();
clang_thread_.interrupt();
clang_thread_.join();
}
// We need this mostly so that we can not use it in tests. Apparently the
// GoogleTest framework goes apeshit on us (on some platforms, in some
// occasions) if we enable threads by default.
void ClangCompleter::EnableThreading() {
threading_enabled_ = true;
InitThreads();
}
std::vector< Diagnostic > ClangCompleter::DiagnosticsForFile(
const std::string &filename ) {
shared_ptr< TranslationUnit > unit;
{
lock_guard< mutex > lock( filename_to_translation_unit_mutex_ );
unit = FindWithDefault(
filename_to_translation_unit_,
filename,
shared_ptr< TranslationUnit >() );
}
if ( !unit )
return std::vector< Diagnostic >();
return unit->LatestDiagnostics();
}
bool ClangCompleter::UpdatingTranslationUnit( const std::string &filename ) {
shared_ptr< TranslationUnit > unit;
{
lock_guard< mutex > lock( filename_to_translation_unit_mutex_ );
unit = FindWithDefault(
filename_to_translation_unit_,
filename,
shared_ptr< TranslationUnit >() );
}
if ( !unit )
return false;
// Thankfully, an invalid, sentinel TU always returns true for
// IsCurrentlyUpdating, so no caller will try to rely on the TU object, even
// if unit is currently pointing to a sentinel.
return unit->IsCurrentlyUpdating();
}
void ClangCompleter::UpdateTranslationUnit(
const std::string &filename,
const std::vector< UnsavedFile > &unsaved_files,
const std::vector< std::string > &flags ) {
bool translation_unit_created;
shared_ptr< TranslationUnit > unit = GetTranslationUnitForFile(
filename,
unsaved_files,
flags,
translation_unit_created );
if ( !unit )
return;
try {
// There's no point in reparsing a TU that was just created, it was just
// parsed in the TU constructor
if ( !translation_unit_created )
unit->Reparse( unsaved_files );
}
catch ( ClangParseError & ) {
lock_guard< mutex > lock( filename_to_translation_unit_mutex_ );
// If unit->Reparse fails, then the underlying TranslationUnit object is not
// valid anymore and needs to be destroyed and removed from the filename ->
// TU map.
Erase( filename_to_translation_unit_, filename );
}
}
Future< void > ClangCompleter::UpdateTranslationUnitAsync(
std::string filename,
std::vector< UnsavedFile > unsaved_files,
std::vector< std::string > flags ) {
function< void() > functor =
bind( &ClangCompleter::UpdateTranslationUnit,
boost::ref( *this ),
boost::move( filename ),
boost::move( unsaved_files ),
boost::move( flags ) );
shared_ptr< ClangPackagedTask > clang_packaged_task =
make_shared< ClangPackagedTask >();
clang_packaged_task->parsing_task_ = packaged_task< void >( functor );
unique_future< void > future =
clang_packaged_task->parsing_task_.get_future();
clang_task_.Set( clang_packaged_task );
return Future< void >( boost::move( future ) );
}
std::vector< CompletionData >
ClangCompleter::CandidatesForLocationInFile(
const std::string &filename,
int line,
int column,
const std::vector< UnsavedFile > &unsaved_files,
const std::vector< std::string > &flags ) {
shared_ptr< TranslationUnit > unit = GetTranslationUnitForFile( filename,
unsaved_files,
flags );
if ( !unit )
return std::vector< CompletionData >();
return unit->CandidatesForLocation( line,
column,
unsaved_files );
}
Future< AsyncCompletions >
ClangCompleter::CandidatesForQueryAndLocationInFileAsync(
const std::string &query,
const std::string &filename,
int line,
int column,
const std::vector< UnsavedFile > &unsaved_files,
const std::vector< std::string > &flags ) {
// TODO: throw exception when threading is not enabled and this is called
if ( !threading_enabled_ )
return Future< AsyncCompletions >();
bool skip_clang_result_cache = ShouldSkipClangResultCache( query,
line,
column );
if ( skip_clang_result_cache ) {
// The clang thread is busy, return nothing
if ( UpdatingTranslationUnit( filename ) )
return Future< AsyncCompletions >();
{
lock_guard< mutex > lock( clang_data_ready_mutex_ );
clang_data_ready_ = false;
}
// Needed to "reset" the sorting threads to the start of their loop. This
// way any threads blocking on a read in sorting_task_.Get() are reset to
// wait on the clang_data_ready_condition_variable_.
sorting_threads_.interrupt_all();
}
// the sorting task needs to be set before the clang task (if any) just in
// case the clang task finishes (and therefore notifies a sorting thread to
// consume a sorting task) before the sorting task is set
unique_future< AsyncCompletions > future;
CreateSortingTask( query, future );
if ( skip_clang_result_cache ) {
CreateClangTask( filename, line, column, unsaved_files, flags );
}
return Future< AsyncCompletions >( boost::move( future ) );
}
bool ClangCompleter::ShouldSkipClangResultCache( const std::string &query,
int line,
int column ) {
// We need query.empty() in addition to the second check because if we don't
// have it, then we have a problem in the following situation:
// The user has a variable 'foo' of type 'A' and a variable 'bar' of type 'B'.
// He then types in 'foo.' and we store the clang results and also return
// them. The user then deletes that code and types in 'bar.'. Without the
// query.empty() check we would return the results from the cache here (it's
// the same line and column!) which would be incorrect.
return query.empty() || latest_clang_results_
.NewPositionDifferentFromStoredPosition( line, column );
}
// Copy-ctor for unique_future is private in C++03 mode so we need to take it as
// an out param
void ClangCompleter::CreateSortingTask(
const std::string &query,
unique_future< AsyncCompletions > &future ) {
// Careful! The code in this function may burn your eyes.
function< CompletionDatas( const CompletionDatas & ) >
sort_candidates_for_query_functor =
bind( &ClangCompleter::SortCandidatesForQuery,
boost::ref( *this ),
query,
_1 );
function< CompletionDatas() > operate_on_completion_data_functor =
bind( &ClangResultsCache::OperateOnCompletionDatas< CompletionDatas >,
boost::cref( latest_clang_results_ ),
boost::move( sort_candidates_for_query_functor ) );
shared_ptr< packaged_task< AsyncCompletions > > task =
make_shared< packaged_task< AsyncCompletions > >(
bind( ReturnValueAsShared< std::vector< CompletionData > >,
boost::move( operate_on_completion_data_functor ) ) );
future = task->get_future();
sorting_task_.Set( task );
}
void ClangCompleter::CreateClangTask(
std::string filename,
int line,
int column,
std::vector< UnsavedFile > unsaved_files,
std::vector< std::string > flags ) {
latest_clang_results_.ResetWithNewLineAndColumn( line, column );
function< CompletionDatas() > candidates_for_location_functor =
bind( &ClangCompleter::CandidatesForLocationInFile,
boost::ref( *this ),
boost::move( filename ),
line,
column,
boost::move( unsaved_files ),
boost::move( flags ) );
shared_ptr< ClangPackagedTask > clang_packaged_task =
make_shared< ClangPackagedTask >();
clang_packaged_task->completions_task_ =
packaged_task< AsyncCompletions >(
bind( ReturnValueAsShared< std::vector< CompletionData > >,
candidates_for_location_functor ) );
clang_task_.Set( clang_packaged_task );
}
boost::shared_ptr< TranslationUnit > ClangCompleter::GetTranslationUnitForFile(
const std::string &filename,
const std::vector< UnsavedFile > &unsaved_files,
const std::vector< std::string > &flags ) {
bool dont_care;
return GetTranslationUnitForFile( filename, unsaved_files, flags, dont_care );
}
// WARNING: It should not be possible to call this function from two separate
// threads at the same time. Currently only one thread (the clang thread) ever
// calls this function so there is no need for a mutex, but if that changes in
// the future a mutex will be needed to make sure that two threads don't try to
// create the same translation unit.
shared_ptr< TranslationUnit > ClangCompleter::GetTranslationUnitForFile(
const std::string &filename,
const std::vector< UnsavedFile > &unsaved_files,
const std::vector< std::string > &flags,
bool &translation_unit_created ) {
{
lock_guard< mutex > lock( filename_to_translation_unit_mutex_ );
TranslationUnitForFilename::iterator it =
filename_to_translation_unit_.find( filename );
if ( it != filename_to_translation_unit_.end() ) {
translation_unit_created = false;
return it->second;
}
// We create and store an invalid, sentinel TU so that other threads don't
// try to create a TU for the same file while we are trying to create this
// TU object. When we are done creating the TU, we will overwrite this value
// with the valid object.
filename_to_translation_unit_[ filename ] =
make_shared< TranslationUnit >();
}
shared_ptr< TranslationUnit > unit;
try {
unit = make_shared< TranslationUnit >(
filename, unsaved_files, flags, clang_index_ );
} catch ( ClangParseError & ) {
Erase( filename_to_translation_unit_, filename );
return unit;
}
{
lock_guard< mutex > lock( filename_to_translation_unit_mutex_ );
filename_to_translation_unit_[ filename ] = unit;
}
translation_unit_created = true;
return unit;
}
std::vector< CompletionData > ClangCompleter::SortCandidatesForQuery(
const std::string &query,
const std::vector< CompletionData > &completion_datas ) {
Bitset query_bitset = LetterBitsetFromString( query );
std::vector< const Candidate * > repository_candidates =
candidate_repository_.GetCandidatesForStrings( completion_datas );
std::vector< CompletionDataAndResult > data_and_results;
for ( uint i = 0; i < repository_candidates.size(); ++i ) {
const Candidate *candidate = repository_candidates[ i ];
if ( !candidate->MatchesQueryBitset( query_bitset ) )
continue;
Result result = candidate->QueryMatchResult( query );
if ( result.IsSubsequence() ) {
CompletionDataAndResult data_and_result( &completion_datas[ i ], result );
data_and_results.push_back( data_and_result );
}
}
std::sort( data_and_results.begin(), data_and_results.end() );
std::vector< CompletionData > sorted_completion_datas;
sorted_completion_datas.reserve( data_and_results.size() );
foreach ( const CompletionDataAndResult & data_and_result,
data_and_results ) {
sorted_completion_datas.push_back( *data_and_result.completion_data_ );
}
return sorted_completion_datas;
}
void ClangCompleter::InitThreads() {
int threads_to_create =
std::max( MIN_ASYNC_THREADS,
std::min( MAX_ASYNC_THREADS, thread::hardware_concurrency() ) );
for ( int i = 0; i < threads_to_create; ++i ) {
sorting_threads_.create_thread( bind( &ClangCompleter::SortingThreadMain,
boost::ref( *this ) ) );
}
clang_thread_ = thread( &ClangCompleter::ClangThreadMain,
boost::ref( *this ) );
}
void ClangCompleter::ClangThreadMain() {
while ( true ) {
try {
shared_ptr< ClangPackagedTask > task = clang_task_.Get();
bool has_completions_task = task->completions_task_.valid();
if ( has_completions_task )
task->completions_task_();
else
task->parsing_task_();
if ( !has_completions_task )
continue;
unique_future< AsyncCompletions > future =
task->completions_task_.get_future();
latest_clang_results_.SetCompletionDatas( *future.get() );
{
lock_guard< mutex > lock( clang_data_ready_mutex_ );
clang_data_ready_ = true;
}
clang_data_ready_condition_variable_.notify_all();
} catch ( thread_interrupted & ) {
shared_lock< shared_mutex > lock( time_to_die_mutex_ );
if ( time_to_die_ )
return;
// else do nothing and re-enter the loop
}
}
}
void ClangCompleter::SortingThreadMain() {
while ( true ) {
try {
{
unique_lock< mutex > lock( clang_data_ready_mutex_ );
while ( !clang_data_ready_ ) {
clang_data_ready_condition_variable_.wait( lock );
}
}
shared_ptr< packaged_task< AsyncCompletions > > task =
sorting_task_.Get();
( *task )();
} catch ( thread_interrupted & ) {
shared_lock< shared_mutex > lock( time_to_die_mutex_ );
if ( time_to_die_ )
return;
// else do nothing and re-enter the loop
}
}
}
} // namespace YouCompleteMe