Refactor Pnacl coordinator

ppapi/native_client/src/trusted/plugin/local_temp_file.h

+// 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 NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_LOCAL_TEMP_FILE_H_
+#define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_LOCAL_TEMP_FILE_H_
+
+#include "native_client/src/include/nacl_macros.h"
+#include "native_client/src/include/nacl_string.h"
+#include "native_client/src/trusted/desc/nacl_desc_rng.h"
+#include "native_client/src/trusted/desc/nacl_desc_wrapper.h"
+
+#include "ppapi/c/trusted/ppb_file_io_trusted.h"
+#include "ppapi/utility/completion_callback_factory.h"
+
+namespace pp {
+class CompletionCallback;
+class FileIO;
+class FileRef;
+class FileSystem;
+}
+
+namespace plugin {
+
+class Plugin;
+
+// Translation creates two temporary files.  The first temporary file holds
+// the object file created by llc.  The second holds the nexe produced by
+// the linker.  Both of these temporary files are used to both write and
+// read according to the following matrix:
+//
+// PnaclCoordinator::obj_file_:
+//     written by: llc     (passed in explicitly through SRPC)
+//     read by:    ld      (returned via lookup service from SRPC)
+// PnaclCoordinator::nexe_file_:
+//     written by: ld      (passed in explicitly through SRPC)
+//     read by:    sel_ldr (passed in explicitly to command channel)
+//
+
+// LocalTempFile represents a file used as a temporary between stages in
+// translation.  It is created in the local temporary file system of the page
+// being processed.  The name of the temporary file is a random 32-character
+// hex string.  Because both reading and writing are necessary, two I/O objects
+// for the file are opened.
+class LocalTempFile {
+ public:
+  // Create a LocalTempFile with a random name.
+  LocalTempFile(Plugin* plugin,
+                pp::FileSystem* file_system,
+                const nacl::string& base_dir);
+  // Create a LocalTempFile with a specific filename.
+  LocalTempFile(Plugin* plugin,
+                pp::FileSystem* file_system,
+                const nacl::string& base_dir,
+                const nacl::string& filename);
+  ~LocalTempFile();
+  // Opens a writeable file IO object and descriptor referring to the file.
+  void OpenWrite(const pp::CompletionCallback& cb);
+  // Opens a read only file IO object and descriptor referring to the file.
+  void OpenRead(const pp::CompletionCallback& cb);
+  // Closes the open descriptors.
+  void Close(const pp::CompletionCallback& cb);
+  // Deletes the temporary file.
+  void Delete(const pp::CompletionCallback& cb);
+  // Renames the temporary file.
+  void Rename(const nacl::string& new_name,
+              const pp::CompletionCallback& cb);
+  void FinishRename();
+
+  // Accessors.
+  // The nacl::DescWrapper* for the writeable version of the file.
+  nacl::DescWrapper* write_wrapper() { return write_wrapper_.get(); }
+  nacl::DescWrapper* release_write_wrapper() {
+    return write_wrapper_.release();
+  }
+  // The nacl::DescWrapper* for the read-only version of the file.
+  nacl::DescWrapper* read_wrapper() { return read_wrapper_.get(); }
+  nacl::DescWrapper* release_read_wrapper() {
+    return read_wrapper_.release();
+  }
+  // For quota management.
+  const nacl::string identifier() const {
+    return nacl::string(reinterpret_cast<const char*>(identifier_));
+  }
+  const pp::FileIO& write_file_io() const { return *write_io_; }
+
+ private:
+  NACL_DISALLOW_COPY_AND_ASSIGN(LocalTempFile);
+
+  void Initialize();
+
+  // Gets the POSIX file descriptor for a resource.
+  int32_t GetFD(int32_t pp_error,
+                const pp::Resource& resource,
+                bool is_writable);
+  // Called when the writable file IO was opened.
+  void WriteFileDidOpen(int32_t pp_error);
+  // Called when the readable file IO was opened.
+  void ReadFileDidOpen(int32_t pp_error);
+  // Completes the close operation after quota update.
+  void CloseContinuation(int32_t pp_error);
+
+  Plugin* plugin_;
+  pp::FileSystem* file_system_;
+  const PPB_FileIOTrusted* file_io_trusted_;
+  pp::CompletionCallbackFactory<LocalTempFile> callback_factory_;
+  nacl::string base_dir_;
+  nacl::string filename_;
+  nacl::scoped_ptr<pp::FileRef> file_ref_;
+  // Temporarily holds the previous file ref during a rename operation.
+  nacl::scoped_ptr<pp::FileRef> old_ref_;
+  // The PPAPI and wrapper state for the writeable file.
+  nacl::scoped_ptr<pp::FileIO> write_io_;
+  nacl::scoped_ptr<nacl::DescWrapper> write_wrapper_;
+  // The PPAPI and wrapper state for the read-only file.
+  nacl::scoped_ptr<pp::FileIO> read_io_;
+  nacl::scoped_ptr<nacl::DescWrapper> read_wrapper_;
+  // The callback invoked when both file I/O objects are created.
+  pp::CompletionCallback done_callback_;
+  // Random number generator used to create filenames.
+  struct NaClDescRng *rng_desc_;
+  // An identifier string used for quota request processing.  The quota
+  // interface needs a string that is unique per sel_ldr instance only, so
+  // the identifiers can be reused between runs of the translator, start-ups of
+  // the browser, etc.
+  uint8_t identifier_[16];
+  // A counter to dole out unique identifiers.
+  static uint32_t next_identifier;
+};
+
+} // namespace plugin
+
+#endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_LOCAL_TEMP_FILE_H_