Added MediaGalleryDatabase

content/browser/media_gallery/media_gallery_database.cc

+// Copyright (c) 2012 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/media_gallery/media_gallery_database.h"
+
+#include <algorithm>
+#include <string>
+
+#include "base/file_path.h"
+#include "base/logging.h"
+#include "sql/diagnostic_error_delegate.h"
+#include "sql/statement.h"
+#include "sql/transaction.h"
+
+#if defined(OS_WIN)
+#include "base/string_util.h"
+#include "base/sys_string_conversions.h"
+#endif  // OS_WIN
+
+#define MEDIA_GALLERY_COLLECTION_ROW_FIELDS \
+    " collections.id, collections.path, collections.last_modified_time, " \
+    "collections.entry_count, collections.all_parsed "
+
+namespace media_gallery {
+
+namespace {
+
+const int kCurrentVersionNumber = 1;
+const int kCompatibleVersionNumber = 1;
+const FilePath::CharType kMediaGalleryDatabaseName[] =
+    FILE_PATH_LITERAL(".media_gallery.db");
+
+class HistogramName {
+ public:
+  static const char* name() {
+    return "Sqlite.MediaGallery.Error";
+  }
+};
+
+}  // namespace
+
+MediaGalleryDatabase::MediaGalleryDatabase() { }
+
+MediaGalleryDatabase::~MediaGalleryDatabase() { }
+
+sql::InitStatus MediaGalleryDatabase::Init(const FilePath& database_dir) {
+  // Set the exceptional sqlite error handler.
+  db_.set_error_delegate(new sql::DiagnosticErrorDelegate<HistogramName>());
+
+  // Set the database page size to something a little larger to give us
+  // better performance (we're typically seek rather than bandwidth limited).
+  // This only has an effect before any tables have been created, otherwise
+  // this is a NOP. Must be a power of 2 and a max of 8192.
+  db_.set_page_size(4096);
+
+  // Increase the cache size. The page size, plus a little extra, times this
+  // value, tells us how much memory the cache will use maximum.
+  // 6000 * 4KB = 24MB
+  db_.set_cache_size(6000);
+
+  if (!db_.Open(database_dir.Append(FilePath(kMediaGalleryDatabaseName))))

[vandebo (ex-Chrome), 2012/03/07 23:28:31]

Should we detect a readonly file system at this point and return a different
error code?

[tpayne, 2012/03/08 00:04:50]

I think that belongs a level above this class.

+    return sql::INIT_FAILURE;
+
+  return InitInternal(&db_);
+}
+
+sql::InitStatus MediaGalleryDatabase::InitInternal(sql::Connection* db) {
+  // Wrap the rest of init in a tranaction. This will prevent the database from
+  // getting corrupted if we crash in the middle of initialization or migration.
+  sql::Transaction committer(db);
+  if (!committer.Begin())
+    return sql::INIT_FAILURE;
+
+  // Prime the cache.
+  db->Preload();
+
+  // Create the tables and indices.
+  if (!meta_table_.Init(db, GetCurrentVersion(), kCompatibleVersionNumber))
+    return sql::INIT_FAILURE;
+
+  if (!CreateCollectionsTable(db))
+    return sql::INIT_FAILURE;
+
+  // Version check.
+  sql::InitStatus version_status = EnsureCurrentVersion();
+  if (version_status != sql::INIT_OK)
+    return version_status;
+
+  return committer.Commit() ? sql::INIT_OK : sql::INIT_FAILURE;
+}
+
+sql::Connection& MediaGalleryDatabase::GetDB() {
+  return db_;
+}
+
+sql::InitStatus MediaGalleryDatabase::EnsureCurrentVersion() {
+  // We can't read databases newer than we were designed for.
+  if (meta_table_.GetCompatibleVersionNumber() > kCurrentVersionNumber) {
+    VLOG(1) << "Media Gallery database is too new.";
+    return sql::INIT_TOO_NEW;
+  }
+  int cur_version = meta_table_.GetVersionNumber();
+  if (cur_version == 0) {
+    DVLOG(1) << "Initializing the Media Gallery database.";
+
+    ++cur_version;
+    meta_table_.SetVersionNumber(cur_version);
+    meta_table_.SetCompatibleVersionNumber(
+        std::min(cur_version, kCompatibleVersionNumber));
+  }
+  return sql::INIT_OK;
+}
+
+// static
+int MediaGalleryDatabase::GetCurrentVersion() {
+  return kCurrentVersionNumber;
+}
+
+CollectionId MediaGalleryDatabase::CreateCollectionRow(
+    CollectionRow* row) {
+  const char* sql = "INSERT INTO collections"
+      "(path, last_modified_time, entry_count, all_parsed) "
+      "VALUES(?, ?, ?, ?)";
+
+  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE, sql));
+#if defined(OS_WIN)
+  // We standardize on UTF8 encoding for paths.
+  std::string path(base::SysWideToUTF8(row->path.value()));
+#elif defined(OS_POSIX)
+  std::string path(row->path.value());
+#endif
+
+#if defined(FILE_PATH_USES_WIN_SEPARATORS)
+  // We standardize on POSIX-style paths, since any platform can understand
+  // them.
+  base::ReplaceChars(path, "\\", "/", &path);

[Lei Zhang, 2012/03/07 21:47:43]

Should this just go up to into the #if defined(OS_WIN) conditional? Very few
places use FILE_PATH_USES_WIN_SEPARATORS.

[tpayne, 2012/03/07 21:49:23]

The two defines go hand in hand (you'll never find one defined without the
other), but semantically I think this one makes more sense here. I am open to
changing it, though.

+#endif  // FILE_PATH_USES_WIN_SEPARATORS
+
+  statement.BindString(0, path.c_str());
+  statement.BindInt64(1, row->last_modified_time.ToInternalValue());
+  statement.BindInt(2, row->entry_count);
+  statement.BindInt(3, row->all_parsed ? 1 : 0);
+
+  if (!statement.Run()) {
+    VLOG(0) << "Failed to add collection " << row->path.value()

[vandebo (ex-Chrome), 2012/03/07 23:28:31]

Should this be a DVLOG(1) ?

[tpayne, 2012/03/08 00:04:50]

I was thinking this may be a useful error message, even in release mode.

+            << " to table media_gallery.collections";
+    return 0;
+  }
+  return row->id = GetDB().GetLastInsertRowId();
+}
+
+bool MediaGalleryDatabase::GetCollectionRow(CollectionId id,
+                                            CollectionRow* row) {
+  sql::Statement statement(GetDB().GetCachedStatement(SQL_FROM_HERE,
+      "SELECT" MEDIA_GALLERY_COLLECTION_ROW_FIELDS
+      "FROM collections WHERE id=?"));
+  statement.BindInt64(0, id);
+
+  if (statement.Step()) {
+    FillCollectionRow(statement, row);
+    return true;
+  }
+  return false;
+}
+
+// Convenience method to fill a row from a statement. Must be in sync with the
+// columns in MEDIA_GALLERY_COLLECTION_ROW_FIELDS
+void MediaGalleryDatabase::FillCollectionRow(const sql::Statement& statement,
+                                             CollectionRow* row) {
+  row->id = statement.ColumnInt64(0);
+#if defined(OS_WIN)
+  row->path = FilePath(base::SysUTF8ToWide(statement.ColumnString(1)));
+#elif defined(OS_POSIX)
+  row->path = FilePath(statement.ColumnString(1));
+#endif  // OS_WIN
+  row->last_modified_time = base::Time::FromInternalValue(
+      statement.ColumnInt64(2));
+  row->entry_count = statement.ColumnInt(3);
+  row->all_parsed = statement.ColumnInt(4) != 0;
+}
+
+// static
+bool MediaGalleryDatabase::DoesCollectionsTableExist(sql::Connection *db) {
+  return db->DoesTableExist("collections");
+}
+
+// static
+bool MediaGalleryDatabase::CreateCollectionsTable(sql::Connection* db) {
+  if (DoesCollectionsTableExist(db))
+    return true;
+
+  // TODO(tpayne): Add unique constraint on path once we standardize on path

[vandebo (ex-Chrome), 2012/03/07 23:28:31]

has the predicate here been satisfied ?

[tpayne, 2012/03/08 00:04:50]

I'd like to leave the TODO to the next CL. In that CL, I've already added the
necessary framework for handling constraint violations.

+  // format.
+  return db->Execute("CREATE TABLE collections"
+                     "(id INTEGER PRIMARY KEY,"
+                     " path LONGVARCHAR NOT NULL,"
+                     " last_modified_time INTEGER NOT NULL,"
+                     " entry_count INTEGER DEFAULT 0 NOT NULL,"
+                     " all_parsed INTEGER DEFAULT 0 NOT NULL)");
+}
+
+}  // namespace media_gallery