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Diffstat (limited to 'mojo/edk/system/message_in_transit.h')
| -rw-r--r-- | mojo/edk/system/message_in_transit.h | 265 |
1 files changed, 0 insertions, 265 deletions
diff --git a/mojo/edk/system/message_in_transit.h b/mojo/edk/system/message_in_transit.h deleted file mode 100644 index 023362a..0000000 --- a/mojo/edk/system/message_in_transit.h +++ /dev/null @@ -1,265 +0,0 @@ -// Copyright 2013 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 MOJO_EDK_SYSTEM_MESSAGE_IN_TRANSIT_H_ -#define MOJO_EDK_SYSTEM_MESSAGE_IN_TRANSIT_H_ - -#include <stddef.h> -#include <stdint.h> - -#include <vector> - -#include "base/macros.h" -#include "base/memory/aligned_memory.h" -#include "base/memory/scoped_ptr.h" -#include "mojo/edk/system/channel_endpoint_id.h" -#include "mojo/edk/system/dispatcher.h" -#include "mojo/edk/system/memory.h" -#include "mojo/edk/system/system_impl_export.h" - -namespace mojo { -namespace system { - -class Channel; -class TransportData; - -// This class is used to represent data in transit. It is thread-unsafe. -// -// |MessageInTransit| buffers: -// -// A |MessageInTransit| can be serialized by writing the main buffer and then, -// if it has one, the transport data buffer. Both buffers are -// |kMessageAlignment|-byte aligned and a multiple of |kMessageAlignment| bytes -// in size. -// -// The main buffer consists of the header (of type |Header|, which is an -// internal detail of this class) followed immediately by the message data -// (accessed by |bytes()| and of size |num_bytes()|, and also -// |kMessageAlignment|-byte aligned), and then any padding needed to make the -// main buffer a multiple of |kMessageAlignment| bytes in size. -// -// See |TransportData| for a description of the (serialized) transport data -// buffer. -class MOJO_SYSTEM_IMPL_EXPORT MessageInTransit { - public: - typedef uint16_t Type; - // Messages that are forwarded to endpoints. - static const Type kTypeEndpoint = 0; - // Messages that are consumed by the |Channel|. - static const Type kTypeChannel = 1; - // Messages that are consumed by the |RawChannel| (implementation). - static const Type kTypeRawChannel = 2; - - typedef uint16_t Subtype; - // Subtypes for type |kTypeEndpoint|: - static const Subtype kSubtypeEndpointData = 0; - // Subtypes for type |kTypeChannel|: - static const Subtype kSubtypeChannelAttachAndRunEndpoint = 0; - static const Subtype kSubtypeChannelRemoveEndpoint = 1; - static const Subtype kSubtypeChannelRemoveEndpointAck = 2; - - // Subtypes for type |kTypeRawChannel|: - static const Subtype kSubtypeRawChannelPosixExtraPlatformHandles = 0; - - // Messages (the header and data) must always be aligned to a multiple of this - // quantity (which must be a power of 2). - static const size_t kMessageAlignment = 8; - - // Forward-declare |Header| so that |View| can use it: - private: - struct Header; - - public: - // This represents a view of serialized message data in a raw buffer. - class MOJO_SYSTEM_IMPL_EXPORT View { - public: - // Constructs a view from the given buffer of the given size. (The size must - // be as provided by |MessageInTransit::GetNextMessageSize()|.) The buffer - // must remain alive/unmodified through the lifetime of this object. - // |buffer| should be |kMessageAlignment|-byte aligned. - View(size_t message_size, const void* buffer); - - // Checks that the given |View| appears to be for a valid message, within - // predetermined limits (e.g., |num_bytes()| and |main_buffer_size()|, that - // |transport_data_buffer()|/|transport_data_buffer_size()| is for valid - // transport data -- see |TransportData::ValidateBuffer()|). - // - // It returns true (and leaves |error_message| alone) if this object appears - // to be a valid message (according to the above) and false, pointing - // |*error_message| to a suitable error message, if not. - bool IsValid(size_t serialized_platform_handle_size, - const char** error_message) const; - - // API parallel to that for |MessageInTransit| itself (mostly getters for - // header data). - const void* main_buffer() const { return buffer_; } - size_t main_buffer_size() const { - return RoundUpMessageAlignment(sizeof(Header) + header()->num_bytes); - } - const void* transport_data_buffer() const { - return (total_size() > main_buffer_size()) - ? static_cast<const char*>(buffer_) + main_buffer_size() - : nullptr; - } - size_t transport_data_buffer_size() const { - return total_size() - main_buffer_size(); - } - size_t total_size() const { return header()->total_size; } - uint32_t num_bytes() const { return header()->num_bytes; } - const void* bytes() const { - return static_cast<const char*>(buffer_) + sizeof(Header); - } - Type type() const { return header()->type; } - Subtype subtype() const { return header()->subtype; } - ChannelEndpointId source_id() const { return header()->source_id; } - ChannelEndpointId destination_id() const { - return header()->destination_id; - } - - private: - const Header* header() const { return static_cast<const Header*>(buffer_); } - - const void* const buffer_; - - // Though this struct is trivial, disallow copy and assign, since it doesn't - // own its data. (If you're copying/assigning this, you're probably doing - // something wrong.) - DISALLOW_COPY_AND_ASSIGN(View); - }; - - // |bytes| is optional; if null, the message data will be zero-initialized. - MessageInTransit(Type type, - Subtype subtype, - uint32_t num_bytes, - const void* bytes); - // |bytes| should be valid (and non-null), unless |num_bytes| is zero. - MessageInTransit(Type type, - Subtype subtype, - uint32_t num_bytes, - UserPointer<const void> bytes); - // Constructs a |MessageInTransit| from a |View|. - explicit MessageInTransit(const View& message_view); - - ~MessageInTransit(); - - // Gets the size of the next message from |buffer|, which has |buffer_size| - // bytes currently available, returning true and setting |*next_message_size| - // on success. |buffer| should be aligned on a |kMessageAlignment| boundary - // (and on success, |*next_message_size| will be a multiple of - // |kMessageAlignment|). - // TODO(vtl): In |RawChannelPosix|, the alignment requirements are currently - // satisified on a faith-based basis. - static bool GetNextMessageSize(const void* buffer, - size_t buffer_size, - size_t* next_message_size); - - // Makes this message "own" the given set of dispatchers. The dispatchers must - // not be referenced from anywhere else (in particular, not from the handle - // table), i.e., each dispatcher must have a reference count of 1. This - // message must not already have dispatchers. - void SetDispatchers(scoped_ptr<DispatcherVector> dispatchers); - - // Sets the |TransportData| for this message. This should only be done when - // there are no dispatchers and no existing |TransportData|. - void SetTransportData(scoped_ptr<TransportData> transport_data); - - // Serializes any dispatchers to the secondary buffer. This message must not - // already have a secondary buffer (so this must only be called once). The - // caller must ensure (e.g., by holding on to a reference) that |channel| - // stays alive through the call. - void SerializeAndCloseDispatchers(Channel* channel); - - // Gets the main buffer and its size (in number of bytes), respectively. - const void* main_buffer() const { return main_buffer_.get(); } - size_t main_buffer_size() const { return main_buffer_size_; } - - // Gets the transport data buffer (if any). - const TransportData* transport_data() const { return transport_data_.get(); } - TransportData* transport_data() { return transport_data_.get(); } - - // Gets the total size of the message (see comment in |Header|, below). - size_t total_size() const { return header()->total_size; } - - // Gets the size of the message data. - uint32_t num_bytes() const { return header()->num_bytes; } - - // Gets the message data (of size |num_bytes()| bytes). - const void* bytes() const { return main_buffer_.get() + sizeof(Header); } - void* bytes() { return main_buffer_.get() + sizeof(Header); } - - Type type() const { return header()->type; } - Subtype subtype() const { return header()->subtype; } - ChannelEndpointId source_id() const { return header()->source_id; } - ChannelEndpointId destination_id() const { return header()->destination_id; } - - void set_source_id(ChannelEndpointId source_id) { - header()->source_id = source_id; - } - void set_destination_id(ChannelEndpointId destination_id) { - header()->destination_id = destination_id; - } - - // Gets the dispatchers attached to this message; this may return null if - // there are none. Note that the caller may mutate the set of dispatchers - // (e.g., take ownership of all the dispatchers, leaving the vector empty). - DispatcherVector* dispatchers() { return dispatchers_.get(); } - - // Returns true if this message has dispatchers attached. - bool has_dispatchers() const { - return dispatchers_ && !dispatchers_->empty(); - } - - // Rounds |n| up to a multiple of |kMessageAlignment|. - static inline size_t RoundUpMessageAlignment(size_t n) { - return (n + kMessageAlignment - 1) & ~(kMessageAlignment - 1); - } - - private: - // To allow us to make compile-assertions about |Header| in the .cc file. - struct PrivateStructForCompileAsserts; - - // Header for the data (main buffer). Must be a multiple of - // |kMessageAlignment| bytes in size. Must be POD. - struct Header { - // Total size of the message, including the header, the message data - // ("bytes") including padding (to make it a multiple of |kMessageAlignment| - // bytes), and serialized handle information. Note that this may not be the - // correct value if dispatchers are attached but - // |SerializeAndCloseDispatchers()| has not been called. - uint32_t total_size; - Type type; // 2 bytes. - Subtype subtype; // 2 bytes. - ChannelEndpointId source_id; // 4 bytes. - ChannelEndpointId destination_id; // 4 bytes. - // Size of actual message data. - uint32_t num_bytes; - uint32_t unused; - }; - - const Header* header() const { - return reinterpret_cast<const Header*>(main_buffer_.get()); - } - Header* header() { return reinterpret_cast<Header*>(main_buffer_.get()); } - - void ConstructorHelper(Type type, Subtype subtype, uint32_t num_bytes); - void UpdateTotalSize(); - - const size_t main_buffer_size_; - const scoped_ptr<char, base::AlignedFreeDeleter> main_buffer_; // Never null. - - scoped_ptr<TransportData> transport_data_; // May be null. - - // Any dispatchers that may be attached to this message. These dispatchers - // should be "owned" by this message, i.e., have a ref count of exactly 1. (We - // allow a dispatcher entry to be null, in case it couldn't be duplicated for - // some reason.) - scoped_ptr<DispatcherVector> dispatchers_; - - DISALLOW_COPY_AND_ASSIGN(MessageInTransit); -}; - -} // namespace system -} // namespace mojo - -#endif // MOJO_EDK_SYSTEM_MESSAGE_IN_TRANSIT_H_ |