Preserve dependencies across multiple index runs.

src/command_line.cc

@@ -895,8 +895,8 @@ bool IndexMain_DoIndex(IndexerConfig* config,
         dep_index_request.args = index_request->args;
         queue_do_index->PriorityEnqueue(std::move(dep_index_request));
       }
-      
-      project->UpdateFileState(index_request->path, old_index->import_file, old_index->last_modification_time);
+
+      project->UpdateFileState(index_request->path, old_index->import_file, old_index->dependencies, old_index->last_modification_time);
 
       Index_DoIdMap response(nullptr, std::move(old_index));
       queue_do_id_map->Enqueue(std::move(response));
@@ -913,11 +913,13 @@ bool IndexMain_DoIndex(IndexerConfig* config,
 
   // Parse request and send a response.
   std::string import_file = index_request->path;
+  std::vector<std::string> import_dependencies;
 
   // Skip index if file modification time didn't change.
   optional<Project::Entry> entry = project->FindCompilationEntryForFile(index_request->path);
   if (entry && entry->last_modification_time) {
     import_file = entry->import_file;
+    import_dependencies = entry->import_dependencies;
 
     int64_t modification_time = GetLastModificationTime(index_request->path);
     if (modification_time == *entry->last_modification_time) {
@@ -926,13 +928,16 @@ bool IndexMain_DoIndex(IndexerConfig* config,
     }
   }
 
-  std::vector<std::unique_ptr<IndexedFile>> indexes = Parse(config, file_consumer_shared, index_request->path, import_file, index_request->args);
+  std::vector<std::unique_ptr<IndexedFile>> indexes = Parse(
+      config, file_consumer_shared,
+      index_request->path, import_file, import_dependencies,
+      index_request->args);
   time.ResetAndPrint("Parsing/indexing " + index_request->path);
 
   for (auto& current_index : indexes) {
     std::cerr << "Got index for " << current_index->path << std::endl;
 
-    project->UpdateFileState(current_index->path, current_index->import_file, current_index->last_modification_time);
+    project->UpdateFileState(current_index->path, current_index->import_file, current_index->dependencies, current_index->last_modification_time);
 
     std::unique_ptr<IndexedFile> old_index = LoadCachedFile(config, current_index->path);
     time.ResetAndPrint("Loading cached index");

src/file_consumer.cc

@@ -50,6 +50,16 @@ IndexedFile* FileConsumer::TryConsumeFile(CXFile file, bool* is_first_ownership)
 }
 
 IndexedFile* FileConsumer::ForceLocal(CXFile file) {
+  // Try to fetch the file using the normal system, which will insert the file
+  // usage into global storage.
+  {
+    bool is_first;
+    IndexedFile* cache = TryConsumeFile(file, &is_first);
+    if (cache)
+      return cache;
+  }
+
+  // It's already been taken before, just create a local copy.
   CXFileUniqueID file_id;
   if (clang_getFileUniqueID(file, &file_id) != 0) {
     std::cerr << "Could not get unique file id for " << FileName(file) << std::endl;
@@ -57,7 +67,7 @@ IndexedFile* FileConsumer::ForceLocal(CXFile file) {
   }
 
   auto it = local_.find(file_id);
-  if (it == local_.end())
+  if (it == local_.end() || !it->second)
     local_[file_id] = MakeUnique<IndexedFile>(FileName(file));
   assert(local_.find(file_id) != local_.end());
   return local_[file_id].get();

src/indexer.cc

@@ -1337,7 +1337,8 @@ void indexEntityReference(CXClientData client_data,
 
 std::vector<std::unique_ptr<IndexedFile>> Parse(
     IndexerConfig* config, FileConsumer::SharedState* file_consumer_shared,
-    std::string desired_index_file, std::string import_file, std::vector<std::string> args,
+    std::string desired_index_file, std::string import_file, const std::vector<std::string>& existing_dependencies,
+    std::vector<std::string> args,
     bool dump_ast) {
 
   if (!config->enableIndexing)
@@ -1391,6 +1392,9 @@ std::vector<std::unique_ptr<IndexedFile>> Parse(
 
     entry->last_modification_time = GetLastModificationTime(entry->path);
     entry->import_file = import_file;
+
+    if (entry->path == import_file && !existing_dependencies.empty())
+      AddRange(&entry->dependencies, existing_dependencies);
   }
 
   // TODO: Fix interesting checks.

src/indexer.h

@@ -502,8 +502,10 @@ struct IndexedFile {
 
 // |import_file| is the cc file which is what gets passed to clang.
 // |desired_index_file| is the (h or cc) file which has actually changed.
+// |dependencies| are the existing dependencies of |import_file| if this is a reparse.
 std::vector<std::unique_ptr<IndexedFile>> Parse(
     IndexerConfig* config, FileConsumer::SharedState* file_consumer_shared,
-    std::string desired_index_file, std::string import_file, std::vector<std::string> args,
+    std::string desired_index_file, std::string import_file, const std::vector<std::string>& existing_dependencies,
+    std::vector<std::string> args,
     bool dump_ast = false);
 void IndexInit();

src/project.cc

@@ -259,7 +259,7 @@ optional<Project::Entry> Project::FindCompilationEntryForFile(const std::string&
   return nullopt;
 }
 
-void Project::UpdateFileState(const std::string& filename, const std::string& import_file, uint64_t modification_time) {
+void Project::UpdateFileState(const std::string& filename, const std::string& import_file, const std::vector<std::string>& import_dependencies, uint64_t modification_time) {
   {
     // TODO: There might be a lot of thread contention here.
     std::lock_guard<std::mutex> lock(entries_modification_mutex_);
@@ -267,6 +267,7 @@ void Project::UpdateFileState(const std::string& filename, const std::string& im
     if (it != absolute_path_to_entry_index_.end()) {
       auto& entry = entries[it->second];
       entry.import_file = import_file;
+      entry.import_dependencies = import_dependencies;
       entry.last_modification_time = modification_time;
       return;
     }
@@ -277,10 +278,12 @@ void Project::UpdateFileState(const std::string& filename, const std::string& im
 
     Project::Entry entry;
     entry.filename = filename;
-    if (import_entry)
+    if (import_entry) {
       entry.args = import_entry->args;
+    }
 
     entry.import_file = import_file;
+    entry.import_dependencies = import_dependencies;
     entry.last_modification_time = modification_time;
     
     // TODO: There might be a lot of thread contention here.

src/project.h

@@ -16,6 +16,7 @@ struct Project {
     std::vector<std::string> args;
     
     std::string import_file;
+    std::vector<std::string> import_dependencies;
     optional<uint64_t> last_modification_time;
   };
 
@@ -35,6 +36,6 @@ struct Project {
   optional<Entry> FindCompilationEntryForFile(const std::string& filename);
 
   // Update the modification time for the given filename. This is thread-safe.
-  void UpdateFileState(const std::string& filename, const std::string& import_file, uint64_t modification_time);
+  void UpdateFileState(const std::string& filename, const std::string& import_file, const std::vector<std::string>& import_dependencies, uint64_t modification_time);
 };
 

src/test.cc

@@ -139,7 +139,7 @@ void RunTests() {
     std::cout << "[START] " << path << std::endl;
     std::vector<std::unique_ptr<IndexedFile>> dbs = Parse(
         &config, &file_consumer_shared,
-        path, path,
+        path, path, {},
         {
           "-xc++",
           "-std=c++11",