Index: chrome/common/descriptor_set_posix.h |
diff --git a/chrome/common/descriptor_set_posix.h b/chrome/common/descriptor_set_posix.h |
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+++ b/chrome/common/descriptor_set_posix.h |
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+// Copyright (c) 2006-2009 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 CHROME_COMMON_DESCRIPTOR_SET_POSIX_H_ |
+#define CHROME_COMMON_DESCRIPTOR_SET_POSIX_H_ |
+ |
+#include <vector> |
+ |
+#include "base/basictypes.h" |
+#include "base/file_descriptor_posix.h" |
+ |
+// ----------------------------------------------------------------------------- |
+// A DescriptorSet is an ordered set of POSIX file descriptors. These are |
+// associated with IPC messages so that descriptors can be transmitted over a |
+// UNIX domain socket. |
+// ----------------------------------------------------------------------------- |
+class DescriptorSet { |
+ public: |
+ DescriptorSet(); |
+ ~DescriptorSet(); |
+ |
+ // This is the maximum number of descriptors per message. We need to know this |
+ // because the control message kernel interface has to be given a buffer which |
+ // is large enough to store all the descriptor numbers. Otherwise the kernel |
+ // tells us that it truncated the control data and the extra descriptors are |
+ // lost. |
+ // |
+ // In debugging mode, it's a fatal error to try and add more than this number |
+ // of descriptors to a DescriptorSet. |
+ enum { |
+ MAX_DESCRIPTORS_PER_MESSAGE = 4, |
+ }; |
+ |
+ // --------------------------------------------------------------------------- |
+ // Interfaces for building during message serialisation... |
+ |
+ // Add a descriptor to the end of the set. Returns false iff the set is full. |
+ bool Add(int fd); |
+ // Add a descriptor to the end of the set and automatically close it after |
+ // transmission. Returns false iff the set is full. |
+ bool AddAndAutoClose(int fd); |
+ |
+ // --------------------------------------------------------------------------- |
+ |
+ |
+ // --------------------------------------------------------------------------- |
+ // Interfaces for accessing during message deserialisation... |
+ |
+ // Return the number of descriptors remaining |
+ unsigned size() const { return descriptors_.size() - next_descriptor_; } |
+ // Return true if no unconsumed descriptors remain |
+ bool empty() const { return descriptors_.size() == next_descriptor_; } |
+ // Fetch the next descriptor from the beginning of the set. This interface is |
+ // designed for the deserialising code as it doesn't support close flags. |
+ // returns: file descriptor, or -1 on error |
+ int NextDescriptor(); |
+ |
+ // --------------------------------------------------------------------------- |
+ |
+ |
+ // --------------------------------------------------------------------------- |
+ // Interfaces for transmission... |
+ |
+ // Fill an array with file descriptors without 'consuming' them. CommitAll |
+ // must be called after these descriptors have been transmitted. |
+ // buffer: (output) a buffer of, at least, size() integers. |
+ void GetDescriptors(int* buffer) const; |
+ // This must be called after transmitting the descriptors returned by |
+ // GetDescriptors. It marks all the descriptors as consumed and closes those |
+ // which are auto-close. |
+ void CommitAll(); |
+ |
+ // --------------------------------------------------------------------------- |
+ |
+ |
+ // --------------------------------------------------------------------------- |
+ // Interfaces for receiving... |
+ |
+ // Set the contents of the set from the given buffer. This set must be empty |
+ // before calling. The auto-close flag is set on all the descriptors so that |
+ // unconsumed descriptors are closed on destruction. |
+ void SetDescriptors(const int* buffer, unsigned count); |
+ |
+ // --------------------------------------------------------------------------- |
+ |
+ // --------------------------------------------------------------------------- |
+ // Interfaces for IPC::Message... |
+ |
+ // Take all the FileDescriptors from another set. Just like a copy |
+ // constructor, except that the source is emptied. |
+ void TakeFrom(DescriptorSet* other); |
+ |
+ // --------------------------------------------------------------------------- |
+ |
+ private: |
+ // A vector of descriptors and close flags. If this message is sent, then |
+ // these descriptors are sent as control data. After sending, any descriptors |
+ // with a true flag are closed. If this message has been received, then these |
+ // are the descriptors which were received and all close flags are true. |
+ std::vector<base::FileDescriptor> descriptors_; |
+ // When deserialising the message, the descriptors will be extracted |
+ // one-by-one. This contains the index of the next unused descriptor. |
+ unsigned next_descriptor_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(DescriptorSet); |
+}; |
+ |
+#endif // CHROME_COMMON_FILE_DESCRIPTOR_POSIX_H_ |