Fix lifetime of leveldb::MojoEnv instances.

components/leveldb/env_mojo.h

 // Copyright 2016 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 COMPONENTS_LEVELDB_ENV_MOJO_H_
 #define COMPONENTS_LEVELDB_ENV_MOJO_H_
 
+#include "base/id_map.h"
 #include "components/filesystem/public/interfaces/directory.mojom.h"
 #include "components/leveldb/leveldb_mojo_proxy.h"
 #include "third_party/leveldatabase/env_chromium.h"
 #include "third_party/leveldatabase/src/include/leveldb/env.h"
 
 namespace leveldb {
 
 // An implementation of the leveldb operating system interaction code which
 // proxies to a specified mojo:filesystem directory. Most of these methods are
 // synchronous and block on responses from the filesystem service. That's fine
 // since, for the most part, they merely open files or check for a file's
 // existence.
 class MojoEnv : public leveldb_env::ChromiumEnv {
  public:
-  MojoEnv(const std::string& name,
-          scoped_refptr<LevelDBMojoProxy> file_thread,
-          LevelDBMojoProxy::OpaqueDir* dir);
-  ~MojoEnv() override;
+  static MojoEnv* Get(
+      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner);
+
+  // Registers a |directory| with the leveldb environment, returning a string
+  // that should be used as prefix to indicate files in that directory.
+  std::string RegisterDirectory(filesystem::mojom::DirectoryPtr directory);
+  void UnregisterDirectory(base::StringPiece prefix);
 
   // Overridden from leveldb_env::EnvChromium:
   Status NewSequentialFile(const std::string& fname,
                            SequentialFile** result) override;
   Status NewRandomAccessFile(const std::string& fname,
                              RandomAccessFile** result) override;
   Status NewWritableFile(const std::string& fname,
                          WritableFile** result) override;
   Status NewAppendableFile(const std::string& fname,
                            WritableFile** result) override;
   bool FileExists(const std::string& fname) override;
   Status GetChildren(const std::string& dir,
                      std::vector<std::string>* result) override;
   Status DeleteFile(const std::string& fname) override;
   Status CreateDir(const std::string& dirname) override;
   Status DeleteDir(const std::string& dirname) override;
   Status GetFileSize(const std::string& fname, uint64_t* file_size) override;
   Status RenameFile(const std::string& src, const std::string& target) override;
   Status LockFile(const std::string& fname, FileLock** lock) override;
   Status UnlockFile(FileLock* lock) override;
   Status GetTestDirectory(std::string* path) override;
   Status NewLogger(const std::string& fname, Logger** result) override;
 
   // For reference, we specifically don't override Schedule(), StartThread(),
   // NowMicros() or SleepForMicroseconds() and use the EnvChromium versions.
 
  private:
+  MojoEnv(scoped_refptr<base::SingleThreadTaskRunner> file_task_runner);
+  ~MojoEnv() override;
+
+  void ParsePath(const std::string& path,
+                 LevelDBMojoProxy::OpaqueDir** out_dir,
+                 std::string* out_path);
+
   scoped_refptr<LevelDBMojoProxy> thread_;
-  LevelDBMojoProxy::OpaqueDir* dir_;
+  IDMap<LevelDBMojoProxy::OpaqueDir*> dirs_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoEnv);
 };
 
 }  // namespace leveldb
 
 #endif  // COMPONENTS_LEVELDB_ENV_MOJO_H_