1 // Copyright (c) 2012 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 "storage/common/blob/shareable_file_reference.h"
6
7 #include <map>
8
9 #include "base/lazy_instance.h"
10 #include "base/message_loop/message_loop_proxy.h"
11 #include "base/task_runner.h"
12 #include "base/threading/non_thread_safe.h"
13
14 namespace storage {
15
16 namespace {
17
18 // A shareable file map with enforcement of thread checker.
19 class ShareableFileMap : public base::NonThreadSafe {
20 public:
21 typedef std::map<base::FilePath, ShareableFileReference*> FileMap;
22 typedef FileMap::iterator iterator;
23 typedef FileMap::key_type key_type;
24 typedef FileMap::value_type value_type;
25
ShareableFileMap()26 ShareableFileMap() {}
27
~ShareableFileMap()28 ~ShareableFileMap() {
29 DetachFromThread();
30 }
31
Find(key_type key)32 iterator Find(key_type key) {
33 DCHECK(CalledOnValidThread());
34 return file_map_.find(key);
35 }
36
End()37 iterator End() {
38 DCHECK(CalledOnValidThread());
39 return file_map_.end();
40 }
41
Insert(value_type value)42 std::pair<iterator, bool> Insert(value_type value) {
43 DCHECK(CalledOnValidThread());
44 return file_map_.insert(value);
45 }
46
Erase(key_type key)47 void Erase(key_type key) {
48 DCHECK(CalledOnValidThread());
49 file_map_.erase(key);
50 }
51
52 private:
53 FileMap file_map_;
54 DISALLOW_COPY_AND_ASSIGN(ShareableFileMap);
55 };
56
57 base::LazyInstance<ShareableFileMap> g_file_map = LAZY_INSTANCE_INITIALIZER;
58
59 } // namespace
60
61 // static
Get(const base::FilePath & path)62 scoped_refptr<ShareableFileReference> ShareableFileReference::Get(
63 const base::FilePath& path) {
64 ShareableFileMap::iterator found = g_file_map.Get().Find(path);
65 ShareableFileReference* reference =
66 (found == g_file_map.Get().End()) ? NULL : found->second;
67 return scoped_refptr<ShareableFileReference>(reference);
68 }
69
70 // static
GetOrCreate(const base::FilePath & path,FinalReleasePolicy policy,base::TaskRunner * file_task_runner)71 scoped_refptr<ShareableFileReference> ShareableFileReference::GetOrCreate(
72 const base::FilePath& path,
73 FinalReleasePolicy policy,
74 base::TaskRunner* file_task_runner) {
75 return GetOrCreate(
76 ScopedFile(path, static_cast<ScopedFile::ScopeOutPolicy>(policy),
77 file_task_runner));
78 }
79
80 // static
GetOrCreate(ScopedFile scoped_file)81 scoped_refptr<ShareableFileReference> ShareableFileReference::GetOrCreate(
82 ScopedFile scoped_file) {
83 if (scoped_file.path().empty())
84 return scoped_refptr<ShareableFileReference>();
85
86 typedef std::pair<ShareableFileMap::iterator, bool> InsertResult;
87 // Required for VS2010:
88 // http://connect.microsoft.com/VisualStudio/feedback/
89 // details/520043/error-converting-from-null-to-a-pointer-type-in-std-pair
90 storage::ShareableFileReference* null_reference = NULL;
91 InsertResult result = g_file_map.Get().Insert(
92 ShareableFileMap::value_type(scoped_file.path(), null_reference));
93 if (result.second == false) {
94 scoped_file.Release();
95 return scoped_refptr<ShareableFileReference>(result.first->second);
96 }
97
98 // Wasn't in the map, create a new reference and store the pointer.
99 scoped_refptr<ShareableFileReference> reference(
100 new ShareableFileReference(scoped_file.Pass()));
101 result.first->second = reference.get();
102 return reference;
103 }
104
AddFinalReleaseCallback(const FinalReleaseCallback & callback)105 void ShareableFileReference::AddFinalReleaseCallback(
106 const FinalReleaseCallback& callback) {
107 DCHECK(g_file_map.Get().CalledOnValidThread());
108 scoped_file_.AddScopeOutCallback(callback, NULL);
109 }
110
ShareableFileReference(ScopedFile scoped_file)111 ShareableFileReference::ShareableFileReference(ScopedFile scoped_file)
112 : scoped_file_(scoped_file.Pass()) {
113 DCHECK(g_file_map.Get().Find(path())->second == NULL);
114 }
115
~ShareableFileReference()116 ShareableFileReference::~ShareableFileReference() {
117 DCHECK(g_file_map.Get().Find(path())->second == this);
118 g_file_map.Get().Erase(path());
119 }
120
121 } // namespace storage
122