text: // 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.
  
  #ifndef WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
  #define WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
  
  #include <string>
  #include <vector>
  
  #include "base/callback_forward.h"
  #include "base/files/file_path.h"
  #include "base/memory/scoped_ptr.h"
  #include "base/platform_file.h"
  #include "webkit/fileapi/file_permission_policy.h"
  #include "webkit/fileapi/file_system_types.h"
  #include "webkit/storage/webkit_storage_export.h"
  
  namespace webkit_blob {
  class FileStreamReader;
  }
  
  namespace fileapi {
  
  class AsyncFileUtil;
  class CopyOrMoveFileValidatorFactory;
  class FileSystemURL;
  class FileStreamWriter;
  class FileSystemContext;
  class FileSystemFileUtil;
  class FileSystemOperation;
  class FileSystemQuotaUtil;
  class RemoteFileSystemProxyInterface;
  
  // An interface to provide mount-point-specific path-related utilities
  // and specialized FileSystemFileUtil instance.
  //
  // NOTE: when you implement a new MountPointProvider for your own
  // FileSystem module, please contact to kinuko@chromium.org.
  //
  class WEBKIT_STORAGE_EXPORT FileSystemMountPointProvider {
   public:
    // Callback for ValidateFileSystemRoot.
    typedef base::Callback<void(base::PlatformFileError error)>
        ValidateFileSystemCallback;
    typedef base::Callback<void(base::PlatformFileError error)>
        DeleteFileSystemCallback;
    virtual ~FileSystemMountPointProvider() {}
  
    // Returns true if this mount point provider can handle |type|.
    // One mount point provider may be able to handle multiple filesystem types.
    virtual bool CanHandleType(FileSystemType type) const = 0;
  
    // Validates the filesystem for the given |origin_url| and |type|.
    // This verifies if it is allowed to request (or create) the filesystem
    // and if it can access (or create) the root directory of the mount point.
    // If |create| is true this may also create the root directory for
    // the filesystem if it doesn't exist.
    virtual void ValidateFileSystemRoot(
        const GURL& origin_url,
        FileSystemType type,
        bool create,
        const ValidateFileSystemCallback& callback) = 0;
  
    // Retrieves the root path of the filesystem specified by the given
    // file system url on the file thread.
    // If |create| is true this may also create the root directory for
    // the filesystem if it doesn't exist.
    virtual base::FilePath GetFileSystemRootPathOnFileThread(
        const FileSystemURL& url,
        bool create) = 0;
  
    // Returns the specialized FileSystemFileUtil for this mount point.
    // It is ok to return NULL if the filesystem doesn't support synchronous
    // version of FileUtil.
    virtual FileSystemFileUtil* GetFileUtil(FileSystemType type) = 0;
  
    // Returns the specialized AsyncFileUtil for this mount point.
    virtual AsyncFileUtil* GetAsyncFileUtil(FileSystemType type) = 0;
  
    // Returns the specialized CopyOrMoveFileValidatorFactory for this mount
    // point and |type|.  If |error_code| is PLATFORM_FILE_OK and the result
    // is NULL, then no validator is required.
    virtual CopyOrMoveFileValidatorFactory* GetCopyOrMoveFileValidatorFactory(
        FileSystemType type, base::PlatformFileError* error_code) = 0;
  
    // Initialize the CopyOrMoveFileValidatorFactory. Invalid to call more than
    // once.
    virtual void InitializeCopyOrMoveFileValidatorFactory(
        FileSystemType type,
        scoped_ptr<CopyOrMoveFileValidatorFactory> factory) = 0;
  
    // Returns file permission policy we should apply for the given |url|.
    virtual FilePermissionPolicy GetPermissionPolicy(
        const FileSystemURL& url,
        int permissions) const = 0;
  
    // Returns a new instance of the specialized FileSystemOperation for this
    // mount point based on the given triplet of |origin_url|, |file_system_type|
    // and |virtual_path|. On failure to create a file system operation, set
    // |error_code| correspondingly.
    // This method is usually dispatched by
    // FileSystemContext::CreateFileSystemOperation.
    virtual FileSystemOperation* CreateFileSystemOperation(
        const FileSystemURL& url,
        FileSystemContext* context,
        base::PlatformFileError* error_code) const = 0;
  
    // Creates a new file stream reader for a given filesystem URL |url| with an
    // offset |offset|. |expected_modification_time| specifies the expected last
    // modification if the value is non-null, the reader will check the underlying
    // file's actual modification time to see if the file has been modified, and
    // if it does any succeeding read operations should fail with
    // ERR_UPLOAD_FILE_CHANGED error.
    // This method itself does *not* check if the given path exists and is a
    // regular file.
    virtual scoped_ptr<webkit_blob::FileStreamReader> CreateFileStreamReader(
      const FileSystemURL& url,
      int64 offset,
      const base::Time& expected_modification_time,
      FileSystemContext* context) const = 0;
  
    // Creates a new file stream writer for a given filesystem URL |url| with an
    // offset |offset|.
    // This method itself does *not* check if the given path exists and is a
    // regular file.
    virtual scoped_ptr<FileStreamWriter> CreateFileStreamWriter(
        const FileSystemURL& url,
        int64 offset,
        FileSystemContext* context) const = 0;
  
    // Returns the specialized FileSystemQuotaUtil for this mount point.
    // This could return NULL if this mount point does not support quota.
    virtual FileSystemQuotaUtil* GetQuotaUtil() = 0;
  
    // Deletes the filesystem for the given |origin_url| and |type|.
    virtual void DeleteFileSystem(
        const GURL& origin_url,
        FileSystemType type,
        FileSystemContext* context,
        const DeleteFileSystemCallback& callback) = 0;
  };
  
  // An interface to control external file system access permissions.
  class ExternalFileSystemMountPointProvider
      : public FileSystemMountPointProvider {
   public:
    // Returns true if |url| is allowed to be accessed.
    // This is supposed to perform ExternalFileSystem-specific security
    // checks. This method is also likely to be called by
    // FileSystemMountPointProvider::GetPermissionPolicy as
    // GetPermissionPolicy is supposed to perform fileapi-generic security
    // checks (which likely need to include ExternalFileSystem-specific checks).
    virtual bool IsAccessAllowed(const fileapi::FileSystemURL& url) const = 0;
    // Returns the list of top level directories that are exposed by this
    // provider. This list is used to set appropriate child process file access
    // permissions.
    virtual std::vector<base::FilePath> GetRootDirectories() const = 0;
    // Grants access to all external file system from extension identified with
    // |extension_id|.
    virtual void GrantFullAccessToExtension(const std::string& extension_id) = 0;
    // Grants access to |virtual_path| from |origin_url|.
    virtual void GrantFileAccessToExtension(
        const std::string& extension_id,
        const base::FilePath& virtual_path) = 0;
    // Revokes file access from extension identified with |extension_id|.
    virtual void RevokeAccessForExtension(
          const std::string& extension_id) = 0;
    // Gets virtual path by known filesystem path. Returns false when filesystem
    // path is not exposed by this provider.
    virtual bool GetVirtualPath(const base::FilePath& file_system_path,
                                base::FilePath* virtual_path) = 0;
  };
  
  }  // namespace fileapi
  
  #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_MOUNT_POINT_PROVIDER_H_
  