Introduce the NotificationIdGenerator in //content.

content/browser/notifications/notification_id_generator.cc

Index: content/browser/notifications/notification_id_generator.cc
diff --git a/content/browser/notifications/notification_id_generator.cc b/content/browser/notifications/notification_id_generator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..252aae478d0476cd323e00007846925c44f909de
--- /dev/null
+++ b/content/browser/notifications/notification_id_generator.cc
@@ -0,0 +1,98 @@
+// Copyright 2015 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.
+
+#include "content/browser/notifications/notification_id_generator.h"
+
+#include <sstream>
+
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "base/sha1.h"
+#include "base/strings/utf_string_conversions.h"
+#include "content/public/browser/browser_context.h"
+#include "url/gurl.h"
+
+namespace content {
+namespace {
+
+const char kSeparator = '#';
+
+// Computes a hash based on the path in which the |browser_context| is stored.
+// Since we only store the hash, SHA-1 is used to make the probability of
+// collisions negligible.
+std::string ComputeBrowserContextHash(BrowserContext* browser_context) {
+  const base::FilePath path = browser_context->GetPath();
+
+#if defined(OS_WIN)
+  return base::SHA1HashString(base::WideToUTF8(path.value()));
+#else
+  return base::SHA1HashString(path.value());
+#endif
+}
+
+}  // namespace
+
+NotificationIdGenerator::NotificationIdGenerator(
+    BrowserContext* browser_context,
+    int render_process_id)
+    : browser_context_(browser_context),
+      render_process_id_(render_process_id) {}
+
+NotificationIdGenerator::~NotificationIdGenerator() {}
+
+std::string NotificationIdGenerator::GenerateForPersistentNotification(
+    const GURL& origin,
+    const std::string& tag,
+    int64_t persistent_notification_id) const {
+  DCHECK(origin.is_valid());
+  DCHECK_EQ(origin, origin.GetOrigin());
+
+  std::stringstream stream;
+
+  stream << ComputeBrowserContextHash(browser_context_);
+  stream << browser_context_->IsOffTheRecord();
+  stream << origin;
+
+  // Persistent notification ids are unique for the lifetime of the notification
+  // database, orthogonal to the renderer that created the notification.
+
+  stream << !!tag.size();
+  if (tag.size())
+    stream << tag;
+  else
+    stream << persistent_notification_id;
+
+  return stream.str();
+}
+
+std::string NotificationIdGenerator::GenerateForNonPersistentNotification(
+    const GURL& origin,
+    const std::string& tag,
+    int non_persistent_notification_id) const {
+  DCHECK(origin.is_valid());
+  DCHECK_EQ(origin, origin.GetOrigin());
+
+  std::stringstream stream;
+
+  stream << ComputeBrowserContextHash(browser_context_);
+  stream << browser_context_->IsOffTheRecord();
+  stream << origin;
+
+  // Non-persistent notification ids are unique per renderer process when no
+  // tag is being used. Tags still identify uniqueness for the given origin.
+
+  stream << !!tag.size();
+  if (!tag.size()) {
+    stream << render_process_id_;
+    stream << kSeparator;
+
+    stream << non_persistent_notification_id;
+  } else {
+    stream << tag;
+  }
+
+  return stream.str();
+}
+
+}  // namespace content