Introducing MemoryMappedExternalResource for creating an external...

src/platform-macos.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 178 matching lines @@
   asm("int $3");
 }
 
 
 class PosixMemoryMappedFile : public OS::MemoryMappedFile {
  public:
   PosixMemoryMappedFile(FILE* file, void* memory, int size)
     : file_(file), memory_(memory), size_(size) { }
   virtual ~PosixMemoryMappedFile();
   virtual void* memory() { return memory_; }
+  virtual int size() { return size_; }
  private:
   FILE* file_;
   void* memory_;
   int size_;
 };
 
 
+OS::MemoryMappedFile* OS::MemoryMappedFile::open(const char* name) {
+  FILE* file = fopen(name, "w+");
+  if (file == NULL) return NULL;
+
+  fseek(file, 0, SEEK_END);
+  int size = ftell(file);
+
+  void* memory =
+      mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fileno(file), 0);
+  return new PosixMemoryMappedFile(file, memory, size);
+}
+
+
 OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size,
     void* initial) {
   FILE* file = fopen(name, "w+");
   if (file == NULL) return NULL;
   int result = fwrite(initial, size, 1, file);
   if (result < 1) {
     fclose(file);
     return NULL;
   }
   void* memory =
@@ skipping 493 matching lines @@
   Top::WakeUpRuntimeProfilerThreadBeforeShutdown();
   pthread_join(data_->sampler_thread_, NULL);
 
   // Deallocate Mach port for thread.
   mach_port_deallocate(data_->task_self_, data_->profiled_thread_);
 }
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal