Revert 98656 - Make a new integer field in sql::MetaTable (a per-profile db) containing a counter...

content/browser/download/download_id.h

-// 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:
-  DownloadId(const DownloadManager* manager, int32 local_id)
-    : 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)); }
-
-  // The following methods (operator==, hash(), copy, and assign) provide
-  // support for STL containers such as hash_map.
-
-  bool operator==(const DownloadId& that) const {
-    return ((that.local_id_ == local_id_) &&
-            (that.manager_ == manager_));
-  }
-  bool operator<(const DownloadId& that) const {
-    // Even though DownloadManager* < DownloadManager* is not well defined and
-    // GCC does not require it for hash_map, MSVC requires operator< for
-    // hash_map. We don't ifdef it out here because we will probably make a
-    // set<DownloadId> at some point, when GCC will require it.
-    return ((that.local_id_ < local_id_) &&
-            (that.manager_ < manager_));
-  }
-
-  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_