commit 54e3dfa2e76af401751b676e6fa150499734e9e6
author dmaclach@chromium.org <dmaclach@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98> Wed Oct 27 18:16:06 2010
committer dmaclach@chromium.org <dmaclach@chromium.org@0039d316-1c4b-4281-b951-d872f2087c98> Wed Oct 27 18:16:06 2010
tree 9b0487732aeaaa36491be79936aa044b47ab8b49
parent 71572873eb78084971b4d1bdd6560f876dc2fada

Fix up SharedMemory implementation so that it is more equivalent on Windows vs Posix and enforces exclusive creates.
Clean up some naming to make it clearer what size you are getting by changing max_size to created_size.

BUG=NONE
TEST=BUILD

Review URL: http://codereview.chromium.org/4034006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64097 0039d316-1c4b-4281-b951-d872f2087c98

base/shared_memory_win.cc

diff --git a/base/shared_memory_win.cc b/base/shared_memory_win.cc
index f35ada1..a0b2a5aa 100644
--- a/base/shared_memory_win.cc
+++ b/base/shared_memory_win.cc
@@ -13,7 +13,7 @@
     : mapped_file_(NULL),
       memory_(NULL),
       read_only_(false),
-      max_size_(0),
+      created_size_(0),
       lock_(NULL) {
 }
 
@@ -21,7 +21,7 @@
     : mapped_file_(handle),
       memory_(NULL),
       read_only_(read_only),
-      max_size_(0),
+      created_size_(0),
       lock_(NULL) {
 }
 
@@ -30,7 +30,7 @@
     : mapped_file_(NULL),
       memory_(NULL),
       read_only_(read_only),
-      max_size_(0),
+      created_size_(0),
       lock_(NULL) {
   ::DuplicateHandle(process, handle,
                     GetCurrentProcess(), &mapped_file_,
@@ -61,9 +61,19 @@
   ::CloseHandle(handle);
 }
 
-bool SharedMemory::Create(const std::string& name, bool read_only,
-                          bool open_existing, uint32 size) {
+bool SharedMemory::CreateAndMapAnonymous(uint32 size) {
+  return CreateAnonymous(size) && Map(size);
+}
+
+bool SharedMemory::CreateAnonymous(uint32 size) {
+  return CreateNamed("", false, size);
+}
+
+bool SharedMemory::CreateNamed(const std::string& name,
+                               bool open_existing, uint32 size) {
   DCHECK(mapped_file_ == NULL);
+  if (size == 0)
+    return false;
 
   // NaCl's memory allocator requires 0mod64K alignment and size for
   // shared memory objects.  To allow passing shared memory to NaCl,
@@ -72,20 +82,25 @@
   // actual requested size.
   uint32 rounded_size = (size + 0xffff) & ~0xffff;
   name_ = ASCIIToWide(name);
-  read_only_ = read_only;
   mapped_file_ = CreateFileMapping(INVALID_HANDLE_VALUE, NULL,
-      read_only_ ? PAGE_READONLY : PAGE_READWRITE, 0,
-      static_cast<DWORD>(rounded_size),
+      PAGE_READWRITE, 0, static_cast<DWORD>(rounded_size),
       name_.empty() ? NULL : name_.c_str());
   if (!mapped_file_)
     return false;
 
+  created_size_ = size;
+
   // Check if the shared memory pre-exists.
-  if (GetLastError() == ERROR_ALREADY_EXISTS && !open_existing) {
-    Close();
-    return false;
+  if (GetLastError() == ERROR_ALREADY_EXISTS) {
+    // If the file already existed, set created_size_ to 0 to show that
+    // we don't know the size.
+    created_size_ = 0;
+    if (!open_existing) {
+      Close();
+      return false;
+    }
   }
-  max_size_ = size;
+
   return true;
 }