sql/mojo/mojo_vfs.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef SQL_MOJO_MOJO_VFS_H_
   6 #define SQL_MOJO_MOJO_VFS_H_
   7
   8 #include "base/macros.h"
   9 #include "components/filesystem/public/interfaces/directory.mojom.h"
  10
  11 typedef struct sqlite3_vfs sqlite3_vfs;
  12
  13 namespace sql {
  14
  15 // Changes the default sqlite3 vfs to a vfs that uses proxies calls to the
  16 // mojo:filesystem service. Instantiating this object transparently changes how
  17 // the entire //sql/ subsystem works in the process of the caller; all paths
  18 // are treated as relative to |directory|.
  19 class ScopedMojoFilesystemVFS {
  20  public:
  21   explicit ScopedMojoFilesystemVFS(filesystem::DirectoryPtr directory);
  22   ~ScopedMojoFilesystemVFS();
  23
  24   // Returns the directory of the current VFS.
  25   filesystem::DirectoryPtr& GetDirectory();
  26
  27  private:
  28   friend sqlite3_vfs* GetParentVFS(sqlite3_vfs* mojo_vfs);
  29   friend filesystem::DirectoryPtr& GetRootDirectory(sqlite3_vfs* mojo_vfs);
  30
  31   // The default vfs at the time MojoVFS was installed. We use the to pass
  32   // through things like randomness requests and per-platform sleep calls.
  33   sqlite3_vfs* parent_;
  34
  35   // When we initialize the subsystem, we are given a filesystem::Directory
  36   // object, which is the root directory of a mojo:filesystem. All access to
  37   // various files are specified from this root directory.
  38   filesystem::DirectoryPtr root_directory_;
  39
  40   DISALLOW_COPY_AND_ASSIGN(ScopedMojoFilesystemVFS);
  41 };
  42
  43 }  // namespace sql
  44
  45 #endif  // SQL_MOJO_MOJO_VFS_H_