Move base to DEPS

base/memory/shared_memory.h

-// Copyright (c) 2012 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.
-
-#ifndef BASE_MEMORY_SHARED_MEMORY_H_
-#define BASE_MEMORY_SHARED_MEMORY_H_
-
-#include "build/build_config.h"
-
-#include <string>
-
-#if defined(OS_POSIX)
-#include <stdio.h>
-#include <sys/types.h>
-#include <semaphore.h>
-#endif
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/memory/shared_memory_handle.h"
-#include "base/process/process_handle.h"
-
-#if defined(OS_POSIX)
-#include "base/file_descriptor_posix.h"
-#include "base/files/file_util.h"
-#include "base/files/scoped_file.h"
-#endif
-
-namespace base {
-
-class FilePath;
-
-// Options for creating a shared memory object.
-struct SharedMemoryCreateOptions {
-  SharedMemoryCreateOptions()
-      : name_deprecated(NULL),
-        size(0),
-        open_existing_deprecated(false),
-        executable(false),
-        share_read_only(false) {}
-
-  // DEPRECATED (crbug.com/345734):
-  // If NULL, the object is anonymous.  This pointer is owned by the caller
-  // and must live through the call to Create().
-  const std::string* name_deprecated;
-
-  // Size of the shared memory object to be created.
-  // When opening an existing object, this has no effect.
-  size_t size;
-
-  // DEPRECATED (crbug.com/345734):
-  // If true, and the shared memory already exists, Create() will open the
-  // existing shared memory and ignore the size parameter.  If false,
-  // shared memory must not exist.  This flag is meaningless unless
-  // name_deprecated is non-NULL.
-  bool open_existing_deprecated;
-
-  // If true, mappings might need to be made executable later.
-  bool executable;
-
-  // If true, the file can be shared read-only to a process.
-  bool share_read_only;
-};
-
-// Platform abstraction for shared memory.  Provides a C++ wrapper
-// around the OS primitive for a memory mapped file.
-class BASE_EXPORT SharedMemory {
- public:
-  SharedMemory();
-
-#if defined(OS_WIN)
-  // Similar to the default constructor, except that this allows for
-  // calling LockDeprecated() to acquire the named mutex before either Create or
-  // Open are called on Windows.
-  explicit SharedMemory(const std::wstring& name);
-#endif
-
-  // Create a new SharedMemory object from an existing, open
-  // shared memory file.
-  //
-  // WARNING: This does not reduce the OS-level permissions on the handle; it
-  // only affects how the SharedMemory will be mmapped.  Use
-  // ShareReadOnlyToProcess to drop permissions.  TODO(jln,jyasskin): DCHECK
-  // that |read_only| matches the permissions of the handle.
-  SharedMemory(const SharedMemoryHandle& handle, bool read_only);
-
-  // Create a new SharedMemory object from an existing, open
-  // shared memory file that was created by a remote process and not shared
-  // to the current process.
-  SharedMemory(const SharedMemoryHandle& handle,
-               bool read_only,
-               ProcessHandle process);
-
-  // Closes any open files.
-  ~SharedMemory();
-
-  // Return true iff the given handle is valid (i.e. not the distingished
-  // invalid value; NULL for a HANDLE and -1 for a file descriptor)
-  static bool IsHandleValid(const SharedMemoryHandle& handle);
-
-  // Returns invalid handle (see comment above for exact definition).
-  static SharedMemoryHandle NULLHandle();
-
-  // Closes a shared memory handle.
-  static void CloseHandle(const SharedMemoryHandle& handle);
-
-  // Returns the maximum number of handles that can be open at once per process.
-  static size_t GetHandleLimit();
-
-  // Duplicates The underlying OS primitive. Returns NULLHandle() on failure.
-  // The caller is responsible for destroying the duplicated OS primitive.
-  static SharedMemoryHandle DuplicateHandle(const SharedMemoryHandle& handle);
-
-#if defined(OS_POSIX)
-  // This method requires that the SharedMemoryHandle is backed by a POSIX fd.
-  static int GetFdFromSharedMemoryHandle(const SharedMemoryHandle& handle);
-#endif
-
-#if defined(OS_POSIX) && !defined(OS_ANDROID)
-  // Returns the size of the shared memory region referred to by |handle|.
-  // Returns '-1' on a failure to determine the size.
-  static int GetSizeFromSharedMemoryHandle(const SharedMemoryHandle& handle);
-#endif  // defined(OS_POSIX) && !defined(OS_ANDROID)
-
-  // Creates a shared memory object as described by the options struct.
-  // Returns true on success and false on failure.
-  bool Create(const SharedMemoryCreateOptions& options);
-
-  // Creates and maps an anonymous shared memory segment of size size.
-  // Returns true on success and false on failure.
-  bool CreateAndMapAnonymous(size_t size);
-
-  // Creates an anonymous shared memory segment of size size.
-  // Returns true on success and false on failure.
-  bool CreateAnonymous(size_t size) {
-    SharedMemoryCreateOptions options;
-    options.size = size;
-    return Create(options);
-  }
-
-  // DEPRECATED (crbug.com/345734):
-  // Creates or opens a shared memory segment based on a name.
-  // If open_existing is true, and the shared memory already exists,
-  // opens the existing shared memory and ignores the size parameter.
-  // If open_existing is false, shared memory must not exist.
-  // size is the size of the block to be created.
-  // Returns true on success, false on failure.
-  bool CreateNamedDeprecated(
-      const std::string& name, bool open_existing, size_t size) {
-    SharedMemoryCreateOptions options;
-    options.name_deprecated = &name;
-    options.open_existing_deprecated = open_existing;
-    options.size = size;
-    return Create(options);
-  }
-
-  // Deletes resources associated with a shared memory segment based on name.
-  // Not all platforms require this call.
-  bool Delete(const std::string& name);
-
-  // Opens a shared memory segment based on a name.
-  // If read_only is true, opens for read-only access.
-  // Returns true on success, false on failure.
-  bool Open(const std::string& name, bool read_only);
-
-  // Maps the shared memory into the caller's address space.
-  // Returns true on success, false otherwise.  The memory address
-  // is accessed via the memory() accessor.  The mapped address is guaranteed to
-  // have an alignment of at least MAP_MINIMUM_ALIGNMENT. This method will fail
-  // if this object is currently mapped.
-  bool Map(size_t bytes) {
-    return MapAt(0, bytes);
-  }
-
-  // Same as above, but with |offset| to specify from begining of the shared
-  // memory block to map.
-  // |offset| must be alignent to value of |SysInfo::VMAllocationGranularity()|.
-  bool MapAt(off_t offset, size_t bytes);
-  enum { MAP_MINIMUM_ALIGNMENT = 32 };
-
-  // Unmaps the shared memory from the caller's address space.
-  // Returns true if successful; returns false on error or if the
-  // memory is not mapped.
-  bool Unmap();
-
-  // The size requested when the map is first created.
-  size_t requested_size() const { return requested_size_; }
-
-  // The actual size of the mapped memory (may be larger than requested).
-  size_t mapped_size() const { return mapped_size_; }
-
-  // Gets a pointer to the opened memory space if it has been
-  // Mapped via Map().  Returns NULL if it is not mapped.
-  void *memory() const { return memory_; }
-
-  // Returns the underlying OS handle for this segment.
-  // Use of this handle for anything other than an opaque
-  // identifier is not portable.
-  SharedMemoryHandle handle() const;
-
-  // Closes the open shared memory segment. The memory will remain mapped if
-  // it was previously mapped.
-  // It is safe to call Close repeatedly.
-  void Close();
-
-  // Shares the shared memory to another process.  Attempts to create a
-  // platform-specific new_handle which can be used in a remote process to read
-  // the shared memory file.  new_handle is an output parameter to receive the
-  // handle for use in the remote process.
-  //
-  // |*this| must have been initialized using one of the Create*() or Open()
-  // methods with share_read_only=true. If it was constructed from a
-  // SharedMemoryHandle, this call will CHECK-fail.
-  //
-  // Returns true on success, false otherwise.
-  bool ShareReadOnlyToProcess(ProcessHandle process,
-                              SharedMemoryHandle* new_handle) {
-    return ShareToProcessCommon(process, new_handle, false, SHARE_READONLY);
-  }
-
-  // Logically equivalent to:
-  //   bool ok = ShareReadOnlyToProcess(process, new_handle);
-  //   Close();
-  //   return ok;
-  // Note that the memory is unmapped by calling this method, regardless of the
-  // return value.
-  bool GiveReadOnlyToProcess(ProcessHandle process,
-                             SharedMemoryHandle* new_handle) {
-    return ShareToProcessCommon(process, new_handle, true, SHARE_READONLY);
-  }
-
-  // Shares the shared memory to another process.  Attempts
-  // to create a platform-specific new_handle which can be
-  // used in a remote process to access the shared memory
-  // file.  new_handle is an output parameter to receive
-  // the handle for use in the remote process.
-  // Returns true on success, false otherwise.
-  bool ShareToProcess(ProcessHandle process,
-                      SharedMemoryHandle* new_handle) {
-    return ShareToProcessCommon(process, new_handle, false, SHARE_CURRENT_MODE);
-  }
-
-  // Logically equivalent to:
-  //   bool ok = ShareToProcess(process, new_handle);
-  //   Close();
-  //   return ok;
-  // Note that the memory is unmapped by calling this method, regardless of the
-  // return value.
-  bool GiveToProcess(ProcessHandle process,
-                     SharedMemoryHandle* new_handle) {
-    return ShareToProcessCommon(process, new_handle, true, SHARE_CURRENT_MODE);
-  }
-
- private:
-#if defined(OS_POSIX) && !defined(OS_NACL) && !defined(OS_ANDROID)
-  bool PrepareMapFile(ScopedFILE fp, ScopedFD readonly);
-  bool FilePathForMemoryName(const std::string& mem_name, FilePath* path);
-#endif  // defined(OS_POSIX) && !defined(OS_NACL) && !defined(OS_ANDROID)
-  enum ShareMode {
-    SHARE_READONLY,
-    SHARE_CURRENT_MODE,
-  };
-  bool ShareToProcessCommon(ProcessHandle process,
-                            SharedMemoryHandle* new_handle,
-                            bool close_self,
-                            ShareMode);
-
-#if defined(OS_WIN)
-  std::wstring       name_;
-  HANDLE             mapped_file_;
-#elif defined(OS_POSIX)
-  int                mapped_file_;
-  int                readonly_mapped_file_;
-#endif
-  size_t             mapped_size_;
-  void*              memory_;
-  bool               read_only_;
-  size_t             requested_size_;
-
-  DISALLOW_COPY_AND_ASSIGN(SharedMemory);
-};
-}  // namespace base
-
-#endif  // BASE_MEMORY_SHARED_MEMORY_H_