| OLD | NEW |
| 1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef BASE_SHARED_MEMORY_H_ | 5 #ifndef BASE_SHARED_MEMORY_H_ |
| 6 #define BASE_SHARED_MEMORY_H_ | 6 #define BASE_SHARED_MEMORY_H_ |
| 7 | 7 |
| 8 #include "build/build_config.h" | 8 #include "build/build_config.h" |
| 9 | 9 |
| 10 #if defined(OS_POSIX) | 10 #if defined(OS_POSIX) |
| (...skipping 22 matching lines...) Expand all Loading... |
| 33 typedef ino_t SharedMemoryId; | 33 typedef ino_t SharedMemoryId; |
| 34 // On POSIX, the lock is implemented as a lockf() on the mapped file, | 34 // On POSIX, the lock is implemented as a lockf() on the mapped file, |
| 35 // so no additional member (or definition of SharedMemoryLock) is | 35 // so no additional member (or definition of SharedMemoryLock) is |
| 36 // needed. | 36 // needed. |
| 37 #endif | 37 #endif |
| 38 | 38 |
| 39 // Platform abstraction for shared memory. Provides a C++ wrapper | 39 // Platform abstraction for shared memory. Provides a C++ wrapper |
| 40 // around the OS primitive for a memory mapped file. | 40 // around the OS primitive for a memory mapped file. |
| 41 class SharedMemory { | 41 class SharedMemory { |
| 42 public: | 42 public: |
| 43 // Create a new SharedMemory object. | |
| 44 SharedMemory(); | 43 SharedMemory(); |
| 45 | 44 |
| 46 // Create a new SharedMemory object from an existing, open | 45 // Create a new SharedMemory object from an existing, open |
| 47 // shared memory file. | 46 // shared memory file. |
| 48 SharedMemory(SharedMemoryHandle handle, bool read_only); | 47 SharedMemory(SharedMemoryHandle handle, bool read_only); |
| 49 | 48 |
| 50 // Create a new SharedMemory object from an existing, open | 49 // Create a new SharedMemory object from an existing, open |
| 51 // shared memory file that was created by a remote process and not shared | 50 // shared memory file that was created by a remote process and not shared |
| 52 // to the current process. | 51 // to the current process. |
| 53 SharedMemory(SharedMemoryHandle handle, bool read_only, | 52 SharedMemory(SharedMemoryHandle handle, bool read_only, |
| 54 base::ProcessHandle process); | 53 ProcessHandle process); |
| 55 | 54 |
| 56 // Destructor. Will close any open files. | 55 // Closes any open files. |
| 57 ~SharedMemory(); | 56 ~SharedMemory(); |
| 58 | 57 |
| 59 // Return true iff the given handle is valid (i.e. not the distingished | 58 // Return true iff the given handle is valid (i.e. not the distingished |
| 60 // invalid value; NULL for a HANDLE and -1 for a file descriptor) | 59 // invalid value; NULL for a HANDLE and -1 for a file descriptor) |
| 61 static bool IsHandleValid(const SharedMemoryHandle& handle); | 60 static bool IsHandleValid(const SharedMemoryHandle& handle); |
| 62 | 61 |
| 63 // Return invalid handle (see comment above for exact definition). | 62 // Returns invalid handle (see comment above for exact definition). |
| 64 static SharedMemoryHandle NULLHandle(); | 63 static SharedMemoryHandle NULLHandle(); |
| 65 | 64 |
| 66 // Close a shared memory handle. | 65 // Closes a shared memory handle. |
| 67 static void CloseHandle(const SharedMemoryHandle& handle); | 66 static void CloseHandle(const SharedMemoryHandle& handle); |
| 68 | 67 |
| 69 // Creates or opens a shared memory segment based on a name. | 68 // Creates or opens a shared memory segment based on a name. |
| 70 // If read_only is true, opens the memory as read-only. | 69 // If read_only is true, opens the memory as read-only. |
| 71 // If open_existing is true, and the shared memory already exists, | 70 // If open_existing is true, and the shared memory already exists, |
| 72 // opens the existing shared memory and ignores the size parameter. | 71 // opens the existing shared memory and ignores the size parameter. |
| 73 // If name is the empty string, use a unique name. | 72 // If name is the empty string, use a unique name. |
| 74 // Returns true on success, false on failure. | 73 // Returns true on success, false on failure. |
| 75 bool Create(const std::wstring& name, bool read_only, bool open_existing, | 74 bool Create(const std::wstring& name, bool read_only, bool open_existing, |
| 76 uint32 size); | 75 uint32 size); |
| (...skipping 22 matching lines...) Expand all Loading... |
| 99 // Note: This size is only available to the creator of the | 98 // Note: This size is only available to the creator of the |
| 100 // shared memory, and not to those that opened shared memory | 99 // shared memory, and not to those that opened shared memory |
| 101 // created externally. | 100 // created externally. |
| 102 // Returns 0 if not opened or unknown. | 101 // Returns 0 if not opened or unknown. |
| 103 uint32 max_size() const { return max_size_; } | 102 uint32 max_size() const { return max_size_; } |
| 104 | 103 |
| 105 // Gets a pointer to the opened memory space if it has been | 104 // Gets a pointer to the opened memory space if it has been |
| 106 // Mapped via Map(). Returns NULL if it is not mapped. | 105 // Mapped via Map(). Returns NULL if it is not mapped. |
| 107 void *memory() const { return memory_; } | 106 void *memory() const { return memory_; } |
| 108 | 107 |
| 109 // Get access to the underlying OS handle for this segment. | 108 // Returns the underlying OS handle for this segment. |
| 110 // Use of this handle for anything other than an opaque | 109 // Use of this handle for anything other than an opaque |
| 111 // identifier is not portable. | 110 // identifier is not portable. |
| 112 SharedMemoryHandle handle() const; | 111 SharedMemoryHandle handle() const; |
| 113 | 112 |
| 114 #if defined(OS_POSIX) | 113 #if defined(OS_POSIX) |
| 115 // Return a unique identifier for this shared memory segment. Inode numbers | 114 // Returns a unique identifier for this shared memory segment. Inode numbers |
| 116 // are technically only unique to a single filesystem. However, we always | 115 // are technically only unique to a single filesystem. However, we always |
| 117 // allocate shared memory backing files from the same directory, so will end | 116 // allocate shared memory backing files from the same directory, so will end |
| 118 // up on the same filesystem. | 117 // up on the same filesystem. |
| 119 SharedMemoryId id() const { return inode_; } | 118 SharedMemoryId id() const { return inode_; } |
| 120 #endif | 119 #endif |
| 121 | 120 |
| 122 // Closes the open shared memory segment. | 121 // Closes the open shared memory segment. |
| 123 // It is safe to call Close repeatedly. | 122 // It is safe to call Close repeatedly. |
| 124 void Close(); | 123 void Close(); |
| 125 | 124 |
| 126 // Share the shared memory to another process. Attempts | 125 // Shares the shared memory to another process. Attempts |
| 127 // to create a platform-specific new_handle which can be | 126 // to create a platform-specific new_handle which can be |
| 128 // used in a remote process to access the shared memory | 127 // used in a remote process to access the shared memory |
| 129 // file. new_handle is an ouput parameter to receive | 128 // file. new_handle is an ouput parameter to receive |
| 130 // the handle for use in the remote process. | 129 // the handle for use in the remote process. |
| 131 // Returns true on success, false otherwise. | 130 // Returns true on success, false otherwise. |
| 132 bool ShareToProcess(base::ProcessHandle process, | 131 bool ShareToProcess(ProcessHandle process, |
| 133 SharedMemoryHandle* new_handle) { | 132 SharedMemoryHandle* new_handle) { |
| 134 return ShareToProcessCommon(process, new_handle, false); | 133 return ShareToProcessCommon(process, new_handle, false); |
| 135 } | 134 } |
| 136 | 135 |
| 137 // Logically equivalent to: | 136 // Logically equivalent to: |
| 138 // bool ok = ShareToProcess(process, new_handle); | 137 // bool ok = ShareToProcess(process, new_handle); |
| 139 // Close(); | 138 // Close(); |
| 140 // return ok; | 139 // return ok; |
| 141 // Note that the memory is unmapped by calling this method, regardless of the | 140 // Note that the memory is unmapped by calling this method, regardless of the |
| 142 // return value. | 141 // return value. |
| 143 bool GiveToProcess(ProcessHandle process, | 142 bool GiveToProcess(ProcessHandle process, |
| 144 SharedMemoryHandle* new_handle) { | 143 SharedMemoryHandle* new_handle) { |
| 145 return ShareToProcessCommon(process, new_handle, true); | 144 return ShareToProcessCommon(process, new_handle, true); |
| 146 } | 145 } |
| 147 | 146 |
| 148 // Lock the shared memory. | 147 // Locks the shared memory. |
| 149 // This is a cross-process lock which may be recursively | 148 // This is a cross-process lock which may be recursively |
| 150 // locked by the same thread. | 149 // locked by the same thread. |
| 151 // TODO(port): | 150 // TODO(port): |
| 152 // WARNING: on POSIX the lock only works across processes, not | 151 // WARNING: on POSIX the lock only works across processes, not |
| 153 // across threads. 2 threads in the same process can both grab the | 152 // across threads. 2 threads in the same process can both grab the |
| 154 // lock at the same time. There are several solutions for this | 153 // lock at the same time. There are several solutions for this |
| 155 // (futex, lockf+anon_semaphore) but none are both clean and common | 154 // (futex, lockf+anon_semaphore) but none are both clean and common |
| 156 // across Mac and Linux. | 155 // across Mac and Linux. |
| 157 void Lock(); | 156 void Lock(); |
| 158 | 157 |
| 159 // Release the shared memory lock. | 158 // Releases the shared memory lock. |
| 160 void Unlock(); | 159 void Unlock(); |
| 161 | 160 |
| 162 private: | 161 private: |
| 163 #if defined(OS_POSIX) | 162 #if defined(OS_POSIX) |
| 164 bool CreateOrOpen(const std::wstring &name, int posix_flags, uint32 size); | 163 bool CreateOrOpen(const std::wstring &name, int posix_flags, uint32 size); |
| 165 bool FilePathForMemoryName(const std::wstring& memname, FilePath* path); | 164 bool FilePathForMemoryName(const std::wstring& memname, FilePath* path); |
| 166 void LockOrUnlockCommon(int function); | 165 void LockOrUnlockCommon(int function); |
| 167 | 166 |
| 168 #endif | 167 #endif |
| 169 bool ShareToProcessCommon(ProcessHandle process, | 168 bool ShareToProcessCommon(ProcessHandle process, |
| (...skipping 31 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
| 201 } | 200 } |
| 202 | 201 |
| 203 private: | 202 private: |
| 204 SharedMemory* shared_memory_; | 203 SharedMemory* shared_memory_; |
| 205 DISALLOW_EVIL_CONSTRUCTORS(SharedMemoryAutoLock); | 204 DISALLOW_EVIL_CONSTRUCTORS(SharedMemoryAutoLock); |
| 206 }; | 205 }; |
| 207 | 206 |
| 208 } // namespace base | 207 } // namespace base |
| 209 | 208 |
| 210 #endif // BASE_SHARED_MEMORY_H_ | 209 #endif // BASE_SHARED_MEMORY_H_ |
| OLD | NEW |