Implement a proxy for Pepper FileIO.

ppapi/shared_impl/ppb_file_io_shared.h

+// 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.
+
+#ifndef PPAPI_SHARED_IMPL_PPB_FILE_IO_SHARED_H_
+#define PPAPI_SHARED_IMPL_PPB_FILE_IO_SHARED_H_
+
+#include <deque>
+
+#include "base/compiler_specific.h"
+#include "ppapi/shared_impl/ppapi_shared_export.h"
+#include "ppapi/shared_impl/resource.h"
+#include "ppapi/thunk/ppb_file_io_api.h"
+
+namespace ppapi {
+
+namespace thunk {
+class PPB_FileRef_API;
+}
+
+class PPAPI_SHARED_EXPORT PPB_FileIO_Shared : public Resource,
+                                              public thunk::PPB_FileIO_API {
+ public:
+  PPB_FileIO_Shared(PP_Instance instance);
+  PPB_FileIO_Shared(const HostResource& host_resource);
+  ~PPB_FileIO_Shared();
+
+  // Resource overrides.
+  virtual void LastPluginRefWasDeleted() OVERRIDE;
+  virtual thunk::PPB_FileIO_API* AsPPB_FileIO_API() OVERRIDE;
+
+  // PPB_FileIO_API implementation.
+  virtual int32_t Open(PP_Resource file_ref,
+                       int32_t open_flags,
+                       PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t Query(PP_FileInfo* info,
+                        PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t Touch(PP_Time last_access_time,
+                        PP_Time last_modified_time,
+                        PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t Read(int64_t offset,
+                       char* buffer,
+                       int32_t bytes_to_read,
+                       PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t Write(int64_t offset,
+                        const char* buffer,
+                        int32_t bytes_to_write,
+                        PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t SetLength(int64_t length,
+                            PP_CompletionCallback callback) OVERRIDE;
+  virtual int32_t Flush(PP_CompletionCallback callback) OVERRIDE;
+
+  // Callback handler for different types of operations.
+  void ExecuteGeneralCallback(int32_t pp_error);
+  void ExecuteOpenFileCallback(int32_t pp_error);
+  void ExecuteQueryCallback(int32_t pp_error, const PP_FileInfo& info);
+  void ExecuteReadCallback(int32_t pp_error, const char* data);
+
+ protected:
+  struct CallbackEntry {
+    CallbackEntry();
+    CallbackEntry(const CallbackEntry& entry);
+    ~CallbackEntry();
+
+    PP_CompletionCallback callback;
+
+    // Pointer back to the caller's read buffer; only used by |Read()|, NULL
+    // for non-read operations. Not owned.
+    char* read_buffer;
+
+    // Pointer back to the caller's PP_FileInfo structure for Query operations.
+    // NULL for non-query operations. Not owned.
+    PP_FileInfo* info;
+  };
+
+  enum OperationType {
+    // There is no pending operation right now.
+    OPERATION_NONE,
+
+    // If there are pending reads, any other kind of async operation is not
+    // allowed.
+    OPERATION_READ,
+
+    // If there are pending writes, any other kind of async operation is not
+    // allowed.
+    OPERATION_WRITE,
+
+    // If there is a pending operation that is neither read nor write, no
+    // further async operation is allowed.
+    OPERATION_EXCLUSIVE
+  };
+
+  // Validated versions of the FileIO API. Subclasses in the proxy and impl
+  // implement these so the common error checking stays here.
+  virtual int32_t OpenValidated(PP_Resource file_ref_resource,
+                                thunk::PPB_FileRef_API* file_ref_api,
+                                int32_t open_flags,
+                                PP_CompletionCallback callback) = 0;
+  virtual int32_t QueryValidated(PP_FileInfo* info,
+                                 PP_CompletionCallback callback) = 0;
+  virtual int32_t TouchValidated(PP_Time last_access_time,
+                                 PP_Time last_modified_time,
+                                 PP_CompletionCallback callback) = 0;
+  virtual int32_t ReadValidated(int64_t offset,
+                                char* buffer,
+                                int32_t bytes_to_read,
+                                PP_CompletionCallback callback) = 0;
+  virtual int32_t WriteValidated(int64_t offset,
+                                 const char* buffer,
+                                 int32_t bytes_to_write,
+                                 PP_CompletionCallback callback) = 0;
+  virtual int32_t SetLengthValidated(int64_t length,
+                                     PP_CompletionCallback callback) = 0;
+  virtual int32_t FlushValidated(PP_CompletionCallback callback) = 0;
+
+  // Called for every "Validated" function.
+  //
+  // This verifies that the callback is valid and that no callback is already
+  // pending, or it is a read(write) request and currently the pending
+  // operations are reads(writes).
+  //
+  // Returns |PP_OK| to indicate that everything is valid or |PP_ERROR_...| if
+  // the call should be aborted and that code returned to the plugin.
+  int32_t CommonCallValidation(bool should_be_open,
+                               OperationType new_op,
+                               PP_CompletionCallback callback);
+
+  // Sets up a pending callback. This should only be called once it is certain
+  // that |PP_OK_COMPLETIONPENDING| will be returned.
+  //
+  // |read_buffer| is only used by read operations, |info| is used only by
+  // query operations.
+  void RegisterCallback(OperationType op,
+                        PP_CompletionCallback callback,
+                        char* read_buffer,
+                        PP_FileInfo* info);
+
+  // Pops the oldest callback from the queue and runs it.
+  void RunAndRemoveFirstPendingCallback(int32_t result);
+
+  // The file system type specified in the Open() call. This will be
+  // PP_FILESYSTEMTYPE_INVALID before open was called. This value does not
+  // indicate that the open command actually succeeded.
+  PP_FileSystemType file_system_type_;
+
+  // Set to true when the file has been successfully opened.
+  bool file_open_;
+
+  std::deque<CallbackEntry> callbacks_;
+  OperationType pending_op_;
+
+  DISALLOW_COPY_AND_ASSIGN(PPB_FileIO_Shared);
+};
+
+}  // namespace ppapi
+
+#endif  // PPAPI_SHARED_IMPL_PPB_FILE_IO_SHARED_H_