3 files changed, 25 insertions, 6 deletions
diff --git a/ppapi/c/dev/pp_file_info_dev.h b/ppapi/c/dev/pp_file_info_dev.h
index dd247fc..782b4f9 100644
--- a/ppapi/c/dev/pp_file_info_dev.h
+++ b/ppapi/c/dev/pp_file_info_dev.h
@@ -17,6 +17,7 @@ typedef enum {
 PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_FileType_Dev, 4);
 
 typedef enum {
+  PP_FILESYSTEMTYPE_INVALID = 0,  /* For identifying invalid return values. */
   PP_FILESYSTEMTYPE_EXTERNAL,
   PP_FILESYSTEMTYPE_LOCALPERSISTENT,
   PP_FILESYSTEMTYPE_LOCALTEMPORARY
diff --git a/ppapi/c/dev/ppb_file_ref_dev.h b/ppapi/c/dev/ppb_file_ref_dev.h
index 4799b34..24cb21d 100644
--- a/ppapi/c/dev/ppb_file_ref_dev.h
+++ b/ppapi/c/dev/ppb_file_ref_dev.h
@@ -24,7 +24,8 @@ struct PPB_FileRef_Dev {
   // resource is invalid or some type other than a FileRef.
   PP_Bool (*IsFileRef)(PP_Resource resource);
 
-  // Returns the file system identifier of this file.
+  // Returns the file system identifier of this file, or
+  // PP_FILESYSTEMTYPE_INVALID if the file ref is invalid.
   PP_FileSystemType_Dev (*GetFileSystemType)(PP_Resource file_ref);
 
   // Returns the name of the file. The value returned by this function does not
diff --git a/ppapi/c/dev/ppb_file_system_dev.h b/ppapi/c/dev/ppb_file_system_dev.h
index 69b18bd..768c35f 100644
--- a/ppapi/c/dev/ppb_file_system_dev.h
+++ b/ppapi/c/dev/ppb_file_system_dev.h
@@ -1,4 +1,4 @@
-/* Copyright (c) 2010 The Chromium Authors. All rights reserved.
+/* 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.
  */
@@ -6,6 +6,7 @@
 #define PPAPI_C_DEV_PPB_FILE_SYSTEM_DEV_H_
 
 #include "ppapi/c/dev/pp_file_info_dev.h"
+#include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_instance.h"
 #include "ppapi/c/pp_resource.h"
 #include "ppapi/c/pp_stdint.h"
@@ -13,17 +14,33 @@
 
 struct PP_CompletionCallback;
 
-#define PPB_FILESYSTEM_DEV_INTERFACE "PPB_FileSystem(Dev);0.3"
+#define PPB_FILESYSTEM_DEV_INTERFACE "PPB_FileSystem(Dev);0.4"
 
 struct PPB_FileSystem_Dev {
-  // Creates a weak pointer to the filesystem of the given type.
+  /** Creates a filesystem object of the given type. */
   PP_Resource (*Create)(PP_Instance instance, PP_FileSystemType_Dev type);
 
-  // Opens the file system. A file system must be opened before running any
-  // other operation on it.
+  /** Returns PP_TRUE if the given resource is a FileSystem. */
+  PP_Bool (*IsFileSystem)(PP_Resource resource);
+
+  /**
+   * Opens the file system. A file system must be opened before running any
+   * other operation on it.
+   *
+   * TODO(brettw) clarify whether this must have completed before a file can
+   * be opened in it. Clarify what it means to be "completed."
+   */
   int32_t (*Open)(PP_Resource file_system,
                   int64_t expected_size,
                   struct PP_CompletionCallback callback);
+
+  /**
+   * Returns the type of the given file system.
+   *
+   * Returns PP_FILESYSTEMTYPE_INVALID if the given resource is not a valid
+   * filesystem. It is valid to call this function even before Open completes.
+   */
+  PP_FileSystemType_Dev (*GetType)(PP_Resource file_system);
 };
 
 #endif  /* PPAPI_C_DEV_PPB_FILE_SYSTEM_DEV_H_ */