Add a MemoryMappedFile class to file_util.

Factor out windowisms from the spell checker.

Review URL: http://codereview.chromium.org/14041

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@6919 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 65 insertions, 1 deletions

diff --git a/base/file_util_win.cc b/base/file_util_win.cc
index db22fa3..c287129 100644
--- a/base/file_util_win.cc
+++ b/base/file_util_win.cc
@@ -595,7 +595,7 @@ bool SetCurrentDirectory(const FilePath& directory) {
 }
 
 ///////////////////////////////////////////////
-
+// FileEnumerator
 
 FileEnumerator::FileEnumerator(const FilePath& root_path,
                                bool recursive,
@@ -694,6 +694,70 @@ FilePath FileEnumerator::Next() {
   return (file_type_ & FileEnumerator::FILES) ? cur_file : Next();
 }
 
+///////////////////////////////////////////////
+// MemoryMappedFile
+
+MemoryMappedFile::MemoryMappedFile()
+    : file_(INVALID_HANDLE_VALUE),
+      file_mapping_(INVALID_HANDLE_VALUE),
+      data_(NULL),
+      length_(INVALID_FILE_SIZE) {
+}
+
+MemoryMappedFile::~MemoryMappedFile() {
+  CloseHandles();
+}
+
+bool MemoryMappedFile::Initialize(const FilePath& file_name) {
+  if (IsValid())
+    return false;
+
+  if (!MapFileToMemory(file_name)) {
+    CloseHandles();
+    return false;
+  }
+
+  return true;
+}
+
+bool MemoryMappedFile::MapFileToMemory(const FilePath& file_name) {
+  file_ = ::CreateFile(file_name.value().c_str(), GENERIC_READ,
+                       FILE_SHARE_READ, NULL, OPEN_EXISTING,
+                       FILE_ATTRIBUTE_NORMAL, NULL);
+  if (file_ == INVALID_HANDLE_VALUE)
+    return false;
+
+  length_ = ::GetFileSize(file_, NULL);
+  if (length_ == INVALID_FILE_SIZE)
+    return false;
+
+  file_mapping_ = ::CreateFileMapping(file_, NULL, PAGE_READONLY,
+                                      0, length_, NULL);
+  if (file_mapping_ == INVALID_HANDLE_VALUE)
+    return false;
+
+  data_ = reinterpret_cast<const uint8*>(
+      ::MapViewOfFile(file_mapping_, FILE_MAP_READ, 0, 0, length_));
+  return data_ != NULL;
+}
+
+bool MemoryMappedFile::IsValid() {
+  return data_ != NULL;
+}
+
+void MemoryMappedFile::CloseHandles() {
+  if (data_)
+    ::UnmapViewOfFile(data_);
+  if (file_mapping_ != INVALID_HANDLE_VALUE)
+    ::CloseHandle(file_mapping_);
+  if (file_ != INVALID_HANDLE_VALUE)
+    ::CloseHandle(file_);
+
+  data_ = NULL;
+  file_mapping_ = file_ = INVALID_HANDLE_VALUE;
+  length_ = INVALID_FILE_SIZE;
+}
+
 // Deprecated functions ----------------------------------------------------
 
 void InsertBeforeExtension(std::wstring* path_str,