Provide assumed favicon for intents if service provider page was never visited.

chrome/browser/history/thumbnail_database.cc

 // 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.
 
 #include "chrome/browser/history/thumbnail_database.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 527 matching lines @@
   sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
       "SELECT id FROM icon_mapping "
       "WHERE icon_id=?"));
   if (!statement)
     return false;
 
   statement.BindInt64(0, id);
   return statement.Step();
 }
 
+bool ThumbnailDatabase::CloneIconMapping(const GURL& old_page_url,
+                                         const GURL& new_page_url) {
+  sql::Statement statement(db_.GetCachedStatement(SQL_FROM_HERE,
+      "SELECT COUNT(*) FROM icon_mapping "
+      "WHERE page_url=?"));
+  if (!statement)
+    return false;
+
+  statement.BindString(0, URLDatabase::GURLToDatabaseURL(new_page_url));
+  if (!statement.Step())
+    return false;
+
+  // Do nothing if there are existing bindings
+  if (statement.ColumnInt(0) != 0)
+    return true;
+
+  statement.Assign(db_.GetCachedStatement(SQL_FROM_HERE,
+      "INSERT INTO icon_mapping (page_url, icon_id) "

[Greg Billock, 2011/11/11 17:47:56]

Will sqlite support a fancier conditional insert here? INSERT INTO SELECT ...
WHERE NOT EXISTS ( SELECT ... FROM ...) or something like that? It's been a
while but I seem to recall you can do this with mysql I think, at least.

[groby-ooo-7-16, 2011/11/14 23:53:36]

yes, fancier statements are supported. Here's what the query would look like:
insert into icon_mapping (page_url, icon_id) select 'foo',icon_id from
icon_mapping where page_url='http://webintents.org/' and not exists (select
icon_id from icon_mapping where page_url='foo');

But

- The query becomes hideously long. Two shorter queries are IMHO easier to
read/reveal the intent.
- The usefulness of the query plan depends on the exact wording of the query.
SQLite doesn't have a decent plan optimizer. 

So leaving it this way for now unless you strongly object.

+        "SELECT ?, icon_id FROM icon_mapping "
+        "WHERE page_url = ?"));
+  if (!statement)
+    return false;
+
+  statement.BindString(0, URLDatabase::GURLToDatabaseURL(new_page_url));
+  statement.BindString(1, URLDatabase::GURLToDatabaseURL(old_page_url));
+  return statement.Run();
+}
+
+
 bool ThumbnailDatabase::MigrateIconMappingData(URLDatabase* url_db) {
   URLDatabase::IconMappingEnumerator e;
   if (!url_db->InitIconMappingEnumeratorForEverything(&e))
     return false;
 
   IconMapping info;
   while (e.GetNextIconMapping(&info)) {
     // TODO: Using bulk insert to improve the performance.
     if (!AddIconMapping(info.page_url, info.icon_id))
       return false;
@@ skipping 195 matching lines @@
   if (!db_.Execute("ALTER TABLE favicons ADD sizes LONGVARCHAR")) {
     NOTREACHED();
     return false;
   }
   meta_table_.SetVersionNumber(5);
   meta_table_.SetCompatibleVersionNumber(std::min(5, kCompatibleVersionNumber));
   return true;
 }
 
 }  // namespace history