A database to hold mappings from origin identifiers to unique directory names.

webkit/fileapi/file_system_origin_database.cc

Index: webkit/fileapi/file_system_origin_database.cc
diff --git a/webkit/fileapi/file_system_origin_database.cc b/webkit/fileapi/file_system_origin_database.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a559c1bf1662f5f8bca80c7b98f32beb307f5b67
--- /dev/null
+++ b/webkit/fileapi/file_system_origin_database.cc
@@ -0,0 +1,190 @@
+// 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 "webkit/fileapi/file_system_origin_database.h"
+
+#include "base/logging.h"
+#include "base/string_number_conversions.h"
+#include "base/string_util.h"
+#include "base/sys_string_conversions.h"
+#include "third_party/leveldb/include/leveldb/iterator.h"
+#include "third_party/leveldb/include/leveldb/write_batch.h"
+
+namespace {
+
+const char kOriginKeyPrefix[] = "ORIGIN:";
+const char kLastPathKey[] = "LAST_PATH";
+
+std::string OriginToOriginKey(const std::string& origin) {
+  std::string key(kOriginKeyPrefix);
+  return key + origin;
+}
+
+const char* LastPathKey() {
+  return kLastPathKey;
+}
+
+}
+
+namespace fileapi {
+
+FileSystemOriginDatabase::FileSystemOriginDatabase(const FilePath& path) {
+#if defined(OS_POSIX)
+  path_ = path.value();
+#elif defined(OS_WIN)
+  path_ = base::SysWideToUTF8(path.value());
+#endif
+}
+
+FileSystemOriginDatabase::~FileSystemOriginDatabase() {
+}
+
+bool FileSystemOriginDatabase::Init() {
+  if (db_.get())
+    return true;
+
+  leveldb::Options options;
+  options.create_if_missing = true;
+  leveldb::DB* db;
+  leveldb::Status status = leveldb::DB::Open(options, path_, &db);
+  if (status.ok()) {
+    db_.reset(db);
+    return true;
+  }
+  HandleError(status);
+  return false;
+}
+
+void FileSystemOriginDatabase::HandleError(leveldb::Status status) {
+  db_.reset();
+  LOG(ERROR) << "FileSystemOriginDatabase failed with error: " <<
+      status.ToString();
+}
+
+bool FileSystemOriginDatabase::HasOriginPath(const std::string& origin) {
+  if (!Init())
+    return false;
+  if (origin.empty())
+    return false;
+  std::string path;
+  leveldb::Status status =
+      db_->Get(leveldb::ReadOptions(), OriginToOriginKey(origin), &path);
+  if (status.ok())
+    return true;
+  if (status.IsNotFound())
+    return false;
+  HandleError(status);
+  return false;
+}
+
+bool FileSystemOriginDatabase::GetPathForOrigin(
+    const std::string& origin, FilePath* directory) {
+  if (!Init())
+    return false;
+  DCHECK(directory);
+  if (origin.empty())
+    return false;
+  std::string path_string;
+  std::string origin_key = OriginToOriginKey(origin);
+  leveldb::Status status =
+      db_->Get(leveldb::ReadOptions(), origin_key, &path_string);
+  if (status.IsNotFound()) {
+    int last_path_number;
+    if (!GetLastPathNumber(&last_path_number))
+      return false;
+    path_string = base::IntToString(last_path_number + 1);
+    // store both back as a single transaction
+    leveldb::WriteBatch batch;
+    batch.Put(LastPathKey(), path_string);
+    batch.Put(origin_key, path_string);
+    status = db_->Write(leveldb::WriteOptions(), &batch);
+    if (!status.ok()) {
+      HandleError(status);
+      return false;
+    }
+  }
+  if (status.ok()) {
+#if defined(OS_POSIX)
+    *directory = FilePath(path_string);
+#elif defined(OS_WIN)
+    *directory = FilePath(base::SysUTF8ToWide(path_string));
+#endif
+    return true;
+  }
+  HandleError(status);
+  return false;
+}
+
+bool FileSystemOriginDatabase::RemovePathForOrigin(const std::string& origin) {
+  if (!Init())
+    return false;
+  leveldb::Status status =
+      db_->Delete(leveldb::WriteOptions(), OriginToOriginKey(origin));
+  if (status.ok() || status.IsNotFound())
+    return true;
+  HandleError(status);
+  return false;
+}
+
+bool FileSystemOriginDatabase::ListAllOrigins(
+    std::vector<OriginRecord>* origins) {
+  if (!Init())
+    return false;
+  DCHECK(origins);
+  scoped_ptr<leveldb::Iterator> iter(db_->NewIterator(leveldb::ReadOptions()));
+  std::string origin_key_prefix = OriginToOriginKey("");
+  iter->Seek(origin_key_prefix);
+  origins->clear();
+  while(iter->Valid() &&
+      StartsWithASCII(iter->key().ToString(), origin_key_prefix, true)) {
+    std::string origin =
+      iter->key().ToString().substr(origin_key_prefix.length());
+#if defined(OS_POSIX)
+    FilePath path = FilePath(iter->value().ToString());
+#elif defined(OS_WIN)
+    FilePath path = FilePath(base::SysUTF8ToWide(iter->value().ToString()));
+#endif
+    origins->push_back(OriginRecord(origin, path));
+    iter->Next();
+  }
+  return true;
+}
+
+void FileSystemOriginDatabase::DropDatabase() {
+  db_.reset();
+}
+
+bool FileSystemOriginDatabase::GetLastPathNumber(int* number) {
+  if (!Init())
+    return false;
+  DCHECK(number);
+  std::string number_string;
+  leveldb::Status status =
+      db_->Get(leveldb::ReadOptions(), LastPathKey(), &number_string);
+  if (status.ok())
+    return base::StringToInt(number_string, number);
+  if (!status.IsNotFound()) {
+    HandleError(status);
+    return false;
+  }
+  // Verify that this is a totally new database, and initialize it.
+  scoped_ptr<leveldb::Iterator> iter(db_->NewIterator(leveldb::ReadOptions()));
+  iter->SeekToFirst();
+  if (iter->Valid()) {  // DB was not empty, but had no last path number!
+    LOG(ERROR) << "File system origin database is corrupt!";
+    return false;
+  }
+  // This is always the first write into the database.  If we ever add a
+  // version number, they should go in in a single transaction.
+  status =
+      db_->Put(leveldb::WriteOptions(), LastPathKey(), std::string("-1"));
+  if (!status.ok()) {
+    HandleError(status);
+    return false;
+  }
+  *number = -1;
+  return true;
+}
+
+}  // namespace fileapi