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-rw-r--r--dom/heapsnapshot/AutoMemMap.cpp64
1 files changed, 64 insertions, 0 deletions
diff --git a/dom/heapsnapshot/AutoMemMap.cpp b/dom/heapsnapshot/AutoMemMap.cpp
new file mode 100644
index 000000000..e725a99c6
--- /dev/null
+++ b/dom/heapsnapshot/AutoMemMap.cpp
@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/devtools/AutoMemMap.h"
+
+#include "mozilla/Unused.h"
+#include "nsDebug.h"
+
+namespace mozilla {
+namespace devtools {
+
+AutoMemMap::~AutoMemMap()
+{
+ if (addr) {
+ Unused << NS_WARN_IF(PR_MemUnmap(addr, size()) != PR_SUCCESS);
+ addr = nullptr;
+ }
+
+ if (fileMap) {
+ Unused << NS_WARN_IF(PR_CloseFileMap(fileMap) != PR_SUCCESS);
+ fileMap = nullptr;
+ }
+
+ if (fd) {
+ Unused << NS_WARN_IF(PR_Close(fd) != PR_SUCCESS);
+ fd = nullptr;
+ }
+}
+
+nsresult
+AutoMemMap::init(const char* filePath, int flags, int mode, PRFileMapProtect prot)
+{
+ MOZ_ASSERT(!fd);
+ MOZ_ASSERT(!fileMap);
+ MOZ_ASSERT(!addr);
+
+ if (PR_GetFileInfo64(filePath, &fileInfo) != PR_SUCCESS)
+ return NS_ERROR_FILE_NOT_FOUND;
+
+ // Check if the file is too big to memmap.
+ if (fileInfo.size > int64_t(UINT32_MAX))
+ return NS_ERROR_INVALID_ARG;
+ auto length = uint32_t(fileInfo.size);
+
+ fd = PR_Open(filePath, flags, flags);
+ if (!fd)
+ return NS_ERROR_UNEXPECTED;
+
+ fileMap = PR_CreateFileMap(fd, fileInfo.size, prot);
+ if (!fileMap)
+ return NS_ERROR_UNEXPECTED;
+
+ addr = PR_MemMap(fileMap, 0, length);
+ if (!addr)
+ return NS_ERROR_UNEXPECTED;
+
+ return NS_OK;
+}
+
+} // namespace devtools
+} // namespace mozilla