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      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_TEMPORARY_FILE_H_
      6 #define NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_TEMPORARY_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_wrapper.h"
     11 
     12 #include "ppapi/c/private/pp_file_handle.h"
     13 #include "ppapi/cpp/completion_callback.h"
     14 
     15 namespace plugin {
     16 
     17 class Plugin;
     18 
     19 // Translation creates two temporary files.  The first temporary file holds
     20 // the object file created by llc.  The second holds the nexe produced by
     21 // the linker.  Both of these temporary files are used to both write and
     22 // read according to the following matrix:
     23 //
     24 // PnaclCoordinator::obj_file_:
     25 //     written by: llc     (passed in explicitly through SRPC)
     26 //     read by:    ld      (returned via lookup service from SRPC)
     27 // PnaclCoordinator::nexe_file_:
     28 //     written by: ld      (passed in explicitly through SRPC)
     29 //     read by:    sel_ldr (passed in explicitly to command channel)
     30 //
     31 
     32 // TempFile represents a file used as a temporary between stages in
     33 // translation.  It is automatically deleted when all handles are closed
     34 // (or earlier -- immediately unlinked on POSIX systems).  The file is only
     35 // opened, once, but because both reading and writing are necessary (and in
     36 // different processes), the user should reset / seek back to the beginning
     37 // of the file between sessions.
     38 class TempFile {
     39  public:
     40   // Create a TempFile.
     41   explicit TempFile(Plugin* plugin);
     42   ~TempFile();
     43 
     44   // Set an existing Fd instead of getting one from the nacl interface on open.
     45   // Must be called before Open.
     46   bool SetExistingFd(PP_FileHandle handle);
     47   // Opens a temporary file object and descriptor wrapper referring to the file.
     48   // If |writeable| is true, the descriptor will be opened for writing, and
     49   // write_wrapper will return a valid pointer, otherwise it will return NULL.
     50   void Open(const pp::CompletionCallback& cb, bool writeable);
     51   // Resets file position of the handle, for reuse.
     52   bool Reset();
     53 
     54   // Accessors.
     55   // The nacl::DescWrapper* for the writeable version of the file.
     56   nacl::DescWrapper* write_wrapper() { return write_wrapper_.get(); }
     57   nacl::DescWrapper* read_wrapper() { return read_wrapper_.get(); }
     58   nacl::DescWrapper* release_read_wrapper() {
     59     return read_wrapper_.release();
     60   }
     61 
     62   // For quota management.
     63   const nacl::string identifier() const {
     64     return nacl::string(reinterpret_cast<const char*>(identifier_));
     65   }
     66 
     67  private:
     68   NACL_DISALLOW_COPY_AND_ASSIGN(TempFile);
     69 
     70   Plugin* plugin_;
     71   nacl::scoped_ptr<nacl::DescWrapper> read_wrapper_;
     72   nacl::scoped_ptr<nacl::DescWrapper> write_wrapper_;
     73   PP_FileHandle existing_handle_;
     74 
     75   // An identifier string used for quota request processing.  The quota
     76   // interface needs a string that is unique per sel_ldr instance only, so
     77   // the identifiers can be reused between runs of the translator, start-ups of
     78   // the browser, etc.
     79   uint8_t identifier_[16];
     80   // A counter to dole out unique identifiers.
     81   static uint32_t next_identifier;
     82 };
     83 
     84 }  // namespace plugin
     85 
     86 #endif  // NATIVE_CLIENT_SRC_TRUSTED_PLUGIN_TEMPORARY_FILE_H_
     87