tor-browser

The Tor Browser
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AutoMemMap.h (2128B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
      2 /* This Source Code Form is subject to the terms of the Mozilla Public
      3 * License, v. 2.0. If a copy of the MPL was not distributed with this
      4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      5 
      6 #ifndef loader_AutoMemMap_h
      7 #define loader_AutoMemMap_h
      8 
      9 #include "mozilla/FileUtils.h"
     10 #include "mozilla/RangedPtr.h"
     11 #include "mozilla/Result.h"
     12 
     13 #include <prio.h>
     14 
     15 class nsIFile;
     16 
     17 namespace mozilla {
     18 namespace ipc {
     19 class FileDescriptor;
     20 }
     21 
     22 namespace loader {
     23 
     24 class AutoMemMap {
     25  typedef mozilla::ipc::FileDescriptor FileDescriptor;
     26 
     27 public:
     28  AutoMemMap() = default;
     29 
     30  ~AutoMemMap();
     31 
     32  Result<Ok, nsresult> init(nsIFile* file, int flags = PR_RDONLY, int mode = 0,
     33                            PRFileMapProtect prot = PR_PROT_READONLY);
     34 
     35  Result<Ok, nsresult> init(const FileDescriptor& file,
     36                            PRFileMapProtect prot = PR_PROT_READONLY,
     37                            size_t maybeSize = 0);
     38 
     39  void reset();
     40 
     41  bool initialized() const { return addr; }
     42 
     43  uint32_t size() const { return size_; }
     44 
     45  template <typename T = void>
     46  RangedPtr<T> get() {
     47    MOZ_ASSERT(addr);
     48    return {static_cast<T*>(addr), size_};
     49  }
     50 
     51  template <typename T = void>
     52  const RangedPtr<T> get() const {
     53    MOZ_ASSERT(addr);
     54    return {static_cast<T*>(addr), size_};
     55  }
     56 
     57  size_t nonHeapSizeOfExcludingThis() { return size_; }
     58 
     59  FileDescriptor cloneFileDescriptor() const;
     60  FileDescriptor cloneHandle() const;
     61 
     62  // Makes this mapping persistent. After calling this, the mapped memory
     63  // will remained mapped, even after this instance is destroyed.
     64  void setPersistent() { persistent_ = true; }
     65 
     66 private:
     67  Result<Ok, nsresult> initInternal(PRFileMapProtect prot,
     68                                    size_t maybeSize = 0);
     69 
     70  AutoFDClose fd;
     71  PRFileMap* fileMap = nullptr;
     72 
     73  uint32_t size_ = 0;
     74  void* addr = nullptr;
     75 
     76  bool persistent_ = 0;
     77 
     78  AutoMemMap(const AutoMemMap&) = delete;
     79  void operator=(const AutoMemMap&) = delete;
     80 };
     81 
     82 }  // namespace loader
     83 }  // namespace mozilla
     84 
     85 #endif  // loader_AutoMemMap_h