Index: chrome/browser/download/download_id.h |
diff --git a/chrome/browser/download/download_id.h b/chrome/browser/download/download_id.h |
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+// Copyright (c) 2011 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#ifndef CHROME_BROWSER_DOWNLOAD_DOWNLOAD_ID_H_ |
+#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_ID_H_ |
+#pragma once |
+ |
+#include <iostream> |
+ |
+#include "base/hash_tables.h" |
+ |
+class DownloadManager; |
+ |
+// DownloadId combines per-profile Download ids with an indication of which |
+// profile in order to be globally unique. DownloadIds are not persistent across |
+// sessions, but their local() field is. |
+class DownloadId { |
+ public: |
+ explicit DownloadId(const DownloadManager* manager = NULL, |
willchan no longer on Chromium
2011/08/06 14:08:36
http://google-styleguide.googlecode.com/svn/trunk/
benjhayden
2011/08/08 16:50:19
Done.
|
+ int32 local_id = -1) |
+ : manager_(manager), |
+ local_id_(local_id) { |
+ } |
+ |
+ // Return the per-profile and persistent part of this DownloadId. |
+ int32 local() const { return local_id_; } |
+ |
+ // Returns true if this DownloadId has been allocated and could possibly refer |
+ // to a DownloadItem that exists. |
+ bool IsValid() const { return ((manager_ != NULL) && (local_id_ >= 0)); } |
+ |
+ // Returns true if this DownloadId was allocated by |manager|. |
+ bool BelongsTo(const DownloadManager* manager) const { |
+ return manager == manager_; |
+ } |
+ |
+ // The following methods (operator==, operator<, hash(), copy, and assign) |
+ // provide support for STL containers such as hash_map and set. |
+ |
+ // Returns true if this refers to the same DownloadItem as that. |
willchan no longer on Chromium
2011/08/06 14:08:36
Where do you need this operator==?
benjhayden
2011/08/08 16:50:19
It looks like hash_map uses operator== on its keys
|
+ bool operator==(const DownloadId& that) const { |
+ return ((that.local_id_ == local_id_) && |
+ (that.manager_ == manager_)); |
+ } |
+ bool operator<(const DownloadId& that) const { |
willchan no longer on Chromium
2011/08/06 14:08:36
operator< does not make sense and I'm not sure you
benjhayden
2011/08/08 16:50:19
Done.
|
+ return ((manager_ < that.manager_) || |
+ (local_id_ < that.local_id_)); |
+ } |
+ |
+ size_t hash() const { |
+ // The top half of manager is unlikely to be distinct, and the user is |
+ // unlikely to have >64K downloads. If these assumptions are incorrect, then |
+ // DownloadFileManager's hash_map might have a few collisions, but it will |
+ // use operator== to safely disambiguate. |
+ return reinterpret_cast<size_t>(manager_) + |
+ (static_cast<size_t>(local_id_) << (4 * sizeof(size_t))); |
+ } |
+ |
+ private: |
+ // DownloadId is used mostly off the UI thread, so manager's methods can't be |
+ // called, but the pointer can be compared. |
+ const DownloadManager* manager_; |
+ |
+ int32 local_id_; |
+ |
+ friend std::ostream& operator<<(std::ostream& out, |
+ const DownloadId& global_id); |
+ |
+ // Allow copy and assign. |
+}; |
+ |
+// Allow logging DownloadIds. Looks like "0x01234567:42". |
+std::ostream& operator<<(std::ostream& out, const DownloadId& global_id); |
+ |
+// Allow using DownloadIds as keys in hash_maps. |
+namespace BASE_HASH_NAMESPACE { |
+#if defined(COMPILER_GCC) |
+template<> struct hash<DownloadId> { |
+ std::size_t operator()(const DownloadId& id) const { |
+ return id.hash(); |
+ } |
+}; |
+#elif defined(COMPILER_MSVC) |
+inline size_t hash_value(const DownloadId& id) { |
+ return id.hash(); |
+} |
+#endif // COMPILER |
+} |
+#endif // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_ID_H_ |