Cleanup: return value and null-callback fixups on AsyncFileUtil interface

- Change return value from bool to void, as handling an error in
  two ways (return value and callback value) adds unnecessary
  complexity, and it's not handled at all in the current code.
- Add a restriction to callbcak: from now callback should never
  be NULL. Also dropping callback.is_null() checks in the implementation.

BUG=241701
TEST=existing tests should pass
R=hidehiko@chromium.org, tzik@chromium.org, vandebo@chromium.org

Review URL: https://codereview.chromium.org/18580012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@210510 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 18 insertions, 41 deletions

diff --git a/webkit/browser/fileapi/async_file_util.h b/webkit/browser/fileapi/async_file_util.h
index 9d51024..e714c99 100644
--- a/webkit/browser/fileapi/async_file_util.h
+++ b/webkit/browser/fileapi/async_file_util.h
@@ -38,6 +38,10 @@ class FileSystemURL;
 // alive while FileSystemOperationContext given to each operation is kept
 // alive. (Note that this instance might be freed on different thread
 // from the thread it is created.)
+//
+// It is NOT valid to give null callback to this class, and implementors
+// can assume that they don't get any null callbacks.
+//
 class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
  public:
   typedef base::Callback<
@@ -79,9 +83,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // LocalFileSystemOperation::OpenFile calls this.
   // This is used only by Pepper/NaCL File API.
   //
-  // This returns false if it fails to post an async task.
-  //
-  virtual bool CreateOrOpen(
+  virtual void CreateOrOpen(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       int file_flags,
@@ -92,8 +94,6 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::CreateFile calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_OK and created==true if a file has not existed and
   //   is created at |url|.
@@ -101,7 +101,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // - Other error code (with created=false) if a file hasn't existed yet
   //   and there was an error while creating a new file.
   //
-  virtual bool EnsureFileExists(
+  virtual void EnsureFileExists(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const EnsureFileExistsCallback& callback) = 0;
@@ -110,8 +110,6 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::CreateDirectory calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if the |url|'s parent directory
   //   does not exist and |recursive| is false.
@@ -121,7 +119,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //   (regardless of |exclusive| value).
   // - Other error code if it failed to create a directory.
   //
-  virtual bool CreateDirectory(
+  virtual void CreateDirectory(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       bool exclusive,
@@ -132,13 +130,11 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::GetMetadata calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if the file doesn't exist.
   // - Other error code if there was an error while retrieving the file info.
   //
-  virtual bool GetFileInfo(
+  virtual void GetFileInfo(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const GetFileInfoCallback& callback) = 0;
@@ -156,14 +152,12 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // the returned |file_list| should include entries whose names
   // are 'a' and 'b', but not '/path/to/dir/a' and '/path/to/dir/b'.)
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if the target directory doesn't exist.
   // - PLATFORM_FILE_ERROR_NOT_A_DIRECTORY if an entry exists at |url| but
   //   is a file (not a directory).
   //
-  virtual bool ReadDirectory(
+  virtual void ReadDirectory(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const ReadDirectoryCallback& callback) = 0;
@@ -175,8 +169,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // LocalFileSystemOperation::TouchFile calls this.
   // This is used only by Pepper/NaCL File API.
   //
-  // This returns false if it fails to post an async task.
-  virtual bool Touch(
+  virtual void Touch(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const base::Time& last_access_time,
@@ -189,12 +182,10 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::Truncate calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if the file doesn't exist.
   //
-  virtual bool Truncate(
+  virtual void Truncate(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       int64 length,
@@ -206,8 +197,6 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::Copy calls this for same-filesystem copy case.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |src_url|
   //   or the parent directory of |dest_url| does not exist.
@@ -217,7 +206,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // - PLATFORM_FILE_ERROR_FAILED if |dest_url| does not exist and
   //   its parent path is a file.
   //
-  virtual bool CopyFileLocal(
+  virtual void CopyFileLocal(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& src_url,
       const FileSystemURL& dest_url,
@@ -229,8 +218,6 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::Move calls this for same-filesystem move case.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |src_url|
   //   or the parent directory of |dest_url| does not exist.
@@ -240,7 +227,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // - PLATFORM_FILE_ERROR_FAILED if |dest_url| does not exist and
   //   its parent path is a file.
   //
-  virtual bool MoveFileLocal(
+  virtual void MoveFileLocal(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& src_url,
       const FileSystemURL& dest_url,
@@ -251,8 +238,6 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // LocalFileSystemOperation::Copy or Move calls this for cross-filesystem
   // cases.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |src_file_path|
   //   or the parent directory of |dest_url| does not exist.
@@ -261,7 +246,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // - PLATFORM_FILE_ERROR_FAILED if |dest_url| does not exist and
   //   its parent path is a file.
   //
-  virtual bool CopyInForeignFile(
+  virtual void CopyInForeignFile(
         scoped_ptr<FileSystemOperationContext> context,
         const base::FilePath& src_file_path,
         const FileSystemURL& dest_url,
@@ -271,13 +256,11 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::RemoveFile calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |url| does not exist.
   // - PLATFORM_FILE_ERROR_NOT_A_FILE if |url| is not a file.
   //
-  virtual bool DeleteFile(
+  virtual void DeleteFile(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const StatusCallback& callback) = 0;
@@ -286,14 +269,12 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::RemoveDirectory calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |url| does not exist.
   // - PLATFORM_FILE_ERROR_NOT_A_DIRECTORY if |url| is not a directory.
   // - PLATFORM_FILE_ERROR_NOT_EMPTY if |url| is not empty.
   //
-  virtual bool DeleteDirectory(
+  virtual void DeleteDirectory(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const StatusCallback& callback) = 0;
@@ -308,12 +289,10 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // This method is optional, so if not supported,
   // PLATFORM_ERROR_INVALID_OPERATION should be returned via |callback|.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |url| does not exist.
   // - PLATFORM_ERROR_INVALID_OPERATION if this operation is not supported.
-  virtual bool DeleteRecursively(
+  virtual void DeleteRecursively(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const StatusCallback& callback) = 0;
@@ -342,8 +321,6 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   //
   // LocalFileSystemOperation::CreateSnapshotFile calls this.
   //
-  // This returns false if it fails to post an async task.
-  //
   // This reports following error code via |callback|:
   // - PLATFORM_FILE_ERROR_NOT_FOUND if |url| does not exist.
   // - PLATFORM_FILE_ERROR_NOT_A_FILE if |url| exists but is a directory.
@@ -351,7 +328,7 @@ class WEBKIT_STORAGE_BROWSER_EXPORT AsyncFileUtil {
   // The field values of |file_info| are undefined (implementation
   // dependent) in error cases, and the caller should always
   // check the return code.
-  virtual bool CreateSnapshotFile(
+  virtual void CreateSnapshotFile(
       scoped_ptr<FileSystemOperationContext> context,
       const FileSystemURL& url,
       const CreateSnapshotFileCallback& callback) = 0;