Upstream android file related code.

base/shared_memory_android.cc

Index: base/shared_memory_android.cc
diff --git a/base/shared_memory_android.cc b/base/shared_memory_android.cc
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index 0000000000000000000000000000000000000000..b999cfa64cf8d270654f8a9b78b19dd37cc050a4
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+++ b/base/shared_memory_android.cc
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+// 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.
+
+#include "base/shared_memory.h"
+
+#include <sys/mman.h>
+
+#include "base/logging.h"
+#include "third_party/ashmem/ashmem.h"
+
+namespace base {
+
+// For Android, we use ashmem to implement SharedMemory. ashmem_create_region
+// will automatically pin the region. We never explicitly call pin/unpin. When
+// all the file descriptors from different processes associated with the region
+// are closed, the memory buffer will go away.
+
+bool SharedMemory::CreateNamed(const std::string& name,
+                               bool open_existing, uint32 size) {
+  DCHECK_EQ(-1, mapped_file_ );
+
+  // "name" is just a label in ashmem. It is visible in /proc/pid/maps.
+  mapped_file_ = ashmem_create_region(name.c_str(), size);
+  if (-1 == mapped_file_) {
+    DLOG(ERROR) << "Shared memory creation failed";
+    return false;
+  }
+
+  int err = ashmem_set_prot_region(mapped_file_,
+                                   PROT_READ | PROT_WRITE | PROT_EXEC);
+  if (err < 0) {
+    DLOG(ERROR) << "Error " << err << " when setting protection of ashmem";
+    return false;
+  }
+  created_size_ = size;
+
+  return true;
+}
+
+bool SharedMemory::Delete(const std::string& name) {
+  // ashmem doesn't support name mapping
+  NOTIMPLEMENTED();
+  return false;
+}
+
+bool SharedMemory::Open(const std::string& name, bool read_only) {
+  // ashmem doesn't support name mapping
+  NOTIMPLEMENTED();
+  return false;
+}
+
+int SharedMemory::GetAshmenSizeRegion() {
+  return ashmem_get_size_region(mapped_file_);
+}
+
+}  // namespace base