1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "tools/gn/import_manager.h"
6
7 #include "base/memory/scoped_ptr.h"
8 #include "base/stl_util.h"
9 #include "tools/gn/parse_tree.h"
10 #include "tools/gn/scheduler.h"
11 #include "tools/gn/scope_per_file_provider.h"
12
13 namespace {
14
15 // Returns a newly-allocated scope on success, null on failure.
UncachedImport(const Settings * settings,const SourceFile & file,const ParseNode * node_for_err,Err * err)16 Scope* UncachedImport(const Settings* settings,
17 const SourceFile& file,
18 const ParseNode* node_for_err,
19 Err* err) {
20 const ParseNode* node = g_scheduler->input_file_manager()->SyncLoadFile(
21 node_for_err->GetRange(), settings->build_settings(), file, err);
22 if (!node)
23 return NULL;
24 const BlockNode* block = node->AsBlock();
25 CHECK(block);
26
27 scoped_ptr<Scope> scope(new Scope(settings->base_config()));
28 scope->set_source_dir(file.GetDir());
29
30 // Don't allow ScopePerFileProvider to provide target-related variables.
31 // These will be relative to the imported file, which is probably not what
32 // people mean when they use these.
33 ScopePerFileProvider per_file_provider(scope.get(), false);
34
35 scope->SetProcessingImport();
36 block->ExecuteBlockInScope(scope.get(), err);
37 if (err->has_error())
38 return NULL;
39 scope->ClearProcessingImport();
40
41 return scope.release();
42 }
43
44 } // namesapce
45
ImportManager()46 ImportManager::ImportManager() {
47 }
48
~ImportManager()49 ImportManager::~ImportManager() {
50 STLDeleteContainerPairSecondPointers(imports_.begin(), imports_.end());
51 }
52
DoImport(const SourceFile & file,const ParseNode * node_for_err,Scope * scope,Err * err)53 bool ImportManager::DoImport(const SourceFile& file,
54 const ParseNode* node_for_err,
55 Scope* scope,
56 Err* err) {
57 // See if we have a cached import, but be careful to actually do the scope
58 // copying outside of the lock.
59 const Scope* imported_scope = NULL;
60 {
61 base::AutoLock lock(lock_);
62 ImportMap::const_iterator found = imports_.find(file);
63 if (found != imports_.end())
64 imported_scope = found->second;
65 }
66
67 if (!imported_scope) {
68 // Do a new import of the file.
69 imported_scope = UncachedImport(scope->settings(), file,
70 node_for_err, err);
71 if (!imported_scope)
72 return false;
73
74 // We loaded the file outside the lock. This means that there could be a
75 // race and the file was already loaded on a background thread. Recover
76 // from this and use the existing one if that happens.
77 {
78 base::AutoLock lock(lock_);
79 ImportMap::const_iterator found = imports_.find(file);
80 if (found != imports_.end()) {
81 delete imported_scope;
82 imported_scope = found->second;
83 } else {
84 imports_[file] = imported_scope;
85 }
86 }
87 }
88
89 Scope::MergeOptions options;
90 options.skip_private_vars = true;
91 options.mark_used = true; // Don't require all imported values be used.
92 return imported_scope->NonRecursiveMergeTo(scope, options, node_for_err,
93 "import", err);
94 }
95