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

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_LOCAL_TEMP_FILE_H_
   6 #define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_LOCAL_TEMP_FILE_H_
   7
   8 #include "native_client/src/include/nacl_macros.h"
   9 #include "native_client/src/include/nacl_string.h"
  10 #include "native_client/src/trusted/desc/nacl_desc_rng.h"
  11 #include "native_client/src/trusted/desc/nacl_desc_wrapper.h"
  12
  13 #include "ppapi/c/trusted/ppb_file_io_trusted.h"
  14 #include "ppapi/utility/completion_callback_factory.h"
  15
  16 namespace pp {
  17 class CompletionCallback;
  18 class FileIO;
  19 class FileRef;
  20 class FileSystem;
  21 }
  22
  23 namespace plugin {
  24
  25 class Plugin;
  26
  27 // Translation creates two temporary files.  The first temporary file holds
  28 // the object file created by llc.  The second holds the nexe produced by
  29 // the linker.  Both of these temporary files are used to both write and
  30 // read according to the following matrix:
  31 //
  32 // PnaclCoordinator::obj_file_:
  33 //     written by: llc     (passed in explicitly through SRPC)
  34 //     read by:    ld      (returned via lookup service from SRPC)
  35 // PnaclCoordinator::nexe_file_:
  36 //     written by: ld      (passed in explicitly through SRPC)
  37 //     read by:    sel_ldr (passed in explicitly to command channel)
  38 //
  39
  40 // LocalTempFile represents a file used as a temporary between stages in
  41 // translation.  It is created in the local temporary file system of the page
  42 // being processed.  The name of the temporary file is a random 32-character
  43 // hex string.  Because both reading and writing are necessary, two I/O objects
  44 // for the file are opened.
  45 class LocalTempFile {
  46  public:
  47   // Create a LocalTempFile with a random name.
  48   LocalTempFile(Plugin* plugin,
  49                 pp::FileSystem* file_system,
  50                 const nacl::string& base_dir);
  51   // Create a LocalTempFile with a specific filename.
  52   LocalTempFile(Plugin* plugin,
  53                 pp::FileSystem* file_system,
  54                 const nacl::string& base_dir,
  55                 const nacl::string& filename);
  56   ~LocalTempFile();
  57   // Opens a writeable file IO object and descriptor referring to the file.
  58   void OpenWrite(const pp::CompletionCallback& cb);
  59   // Opens a read only file IO object and descriptor referring to the file.
  60   void OpenRead(const pp::CompletionCallback& cb);
  61   // Closes the open descriptors.
  62   void Close(const pp::CompletionCallback& cb);
  63   // Deletes the temporary file.
  64   void Delete(const pp::CompletionCallback& cb);
  65   // Renames the temporary file.
  66   void Rename(const nacl::string& new_name,
  67               const pp::CompletionCallback& cb);
  68   void FinishRename();
  69
  70   // Accessors.
  71   // The nacl::DescWrapper* for the writeable version of the file.
  72   nacl::DescWrapper* write_wrapper() { return write_wrapper_.get(); }
  73   nacl::DescWrapper* release_write_wrapper() {
  74     return write_wrapper_.release();
  75   }
  76   // The nacl::DescWrapper* for the read-only version of the file.
  77   nacl::DescWrapper* read_wrapper() { return read_wrapper_.get(); }
  78   nacl::DescWrapper* release_read_wrapper() {
  79     return read_wrapper_.release();
  80   }
  81   // For quota management.
  82   const nacl::string identifier() const {
  83     return nacl::string(reinterpret_cast<const char*>(identifier_));
  84   }
  85   pp::FileIO* write_file_io() const { return write_io_.get(); }
  86
  87  private:
  88   NACL_DISALLOW_COPY_AND_ASSIGN(LocalTempFile);
  89
  90   void Initialize();
  91
  92   // Gets the POSIX file descriptor for a resource.
  93   int32_t GetFD(int32_t pp_error,
  94                 const pp::Resource& resource,
  95                 bool is_writable);
  96   // Called when the writable file IO was opened.
  97   void WriteFileDidOpen(int32_t pp_error);
  98   // Called when the readable file IO was opened.
  99   void ReadFileDidOpen(int32_t pp_error);
 100   // Completes the close operation after quota update.
 101   void CloseContinuation(int32_t pp_error);
 102
 103   Plugin* plugin_;
 104   pp::FileSystem* file_system_;
 105   const PPB_FileIOTrusted* file_io_trusted_;
 106   pp::CompletionCallbackFactory<LocalTempFile> callback_factory_;
 107   nacl::string base_dir_;
 108   nacl::string filename_;
 109   nacl::scoped_ptr<pp::FileRef> file_ref_;
 110   // Temporarily holds the previous file ref during a rename operation.
 111   nacl::scoped_ptr<pp::FileRef> old_ref_;
 112   // The PPAPI and wrapper state for the writeable file.
 113   nacl::scoped_ptr<pp::FileIO> write_io_;
 114   nacl::scoped_ptr<nacl::DescWrapper> write_wrapper_;
 115   // The PPAPI and wrapper state for the read-only file.
 116   nacl::scoped_ptr<pp::FileIO> read_io_;
 117   nacl::scoped_ptr<nacl::DescWrapper> read_wrapper_;
 118   // The callback invoked when both file I/O objects are created.
 119   pp::CompletionCallback done_callback_;
 120   // Random number generator used to create filenames.
 121   struct NaClDescRng *rng_desc_;
 122   // An identifier string used for quota request processing.  The quota
 123   // interface needs a string that is unique per sel_ldr instance only, so
 124   // the identifiers can be reused between runs of the translator, start-ups of
 125   // the browser, etc.
 126   uint8_t identifier_[16];
 127   // A counter to dole out unique identifiers.
 128   static uint32_t next_identifier;
 129 };
 130
 131 }  // namespace plugin
 132
 133 #endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_LOCAL_TEMP_FILE_H_