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Unified Diff: mojo/edk/system/dispatcher.h

Issue 814543006: Move //mojo/{public, edk} underneath //third_party (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: Rebase Created 5 years, 11 months ago
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Index: mojo/edk/system/dispatcher.h
diff --git a/mojo/edk/system/dispatcher.h b/mojo/edk/system/dispatcher.h
deleted file mode 100644
index c069269b1a2bee1aae2eb5c94e2a20ce2857a2a6..0000000000000000000000000000000000000000
--- a/mojo/edk/system/dispatcher.h
+++ /dev/null
@@ -1,405 +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_DISPATCHER_H_
-#define MOJO_EDK_SYSTEM_DISPATCHER_H_
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include <vector>
-
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/synchronization/lock.h"
-#include "mojo/edk/embedder/platform_handle_vector.h"
-#include "mojo/edk/system/handle_signals_state.h"
-#include "mojo/edk/system/memory.h"
-#include "mojo/edk/system/system_impl_export.h"
-#include "mojo/public/c/system/buffer.h"
-#include "mojo/public/c/system/data_pipe.h"
-#include "mojo/public/c/system/message_pipe.h"
-#include "mojo/public/c/system/types.h"
-
-namespace mojo {
-
-namespace embedder {
-class PlatformSharedBufferMapping;
-}
-
-namespace system {
-
-class Channel;
-class Core;
-class Dispatcher;
-class DispatcherTransport;
-class HandleTable;
-class LocalMessagePipeEndpoint;
-class ProxyMessagePipeEndpoint;
-class TransportData;
-class Awakable;
-
-typedef std::vector<scoped_refptr<Dispatcher>> DispatcherVector;
-
-namespace test {
-
-// Test helper. We need to declare it here so we can friend it.
-MOJO_SYSTEM_IMPL_EXPORT DispatcherTransport
-DispatcherTryStartTransport(Dispatcher* dispatcher);
-
-} // namespace test
-
-// A |Dispatcher| implements Mojo primitives that are "attached" to a particular
-// handle. This includes most (all?) primitives except for |MojoWait...()|. This
-// object is thread-safe, with its state being protected by a single lock
-// |lock_|, which is also made available to implementation subclasses (via the
-// |lock()| method).
-class MOJO_SYSTEM_IMPL_EXPORT Dispatcher
- : public base::RefCountedThreadSafe<Dispatcher> {
- public:
- enum Type {
- kTypeUnknown = 0,
- kTypeMessagePipe,
- kTypeDataPipeProducer,
- kTypeDataPipeConsumer,
- kTypeSharedBuffer,
-
- // "Private" types (not exposed via the public interface):
- kTypePlatformHandle = -1
- };
- virtual Type GetType() const = 0;
-
- // These methods implement the various primitives named |Mojo...()|. These
- // take |lock_| and handle races with |Close()|. Then they call out to
- // subclasses' |...ImplNoLock()| methods (still under |lock_|), which actually
- // implement the primitives.
- // NOTE(vtl): This puts a big lock around each dispatcher (i.e., handle), and
- // prevents the various |...ImplNoLock()|s from releasing the lock as soon as
- // possible. If this becomes an issue, we can rethink this.
- MojoResult Close();
-
- // |transports| may be non-null if and only if there are handles to be
- // written; not that |this| must not be in |transports|. On success, all the
- // dispatchers in |transports| must have been moved to a closed state; on
- // failure, they should remain in their original state.
- MojoResult WriteMessage(UserPointer<const void> bytes,
- uint32_t num_bytes,
- std::vector<DispatcherTransport>* transports,
- MojoWriteMessageFlags flags);
- // |dispatchers| must be non-null but empty, if |num_dispatchers| is non-null
- // and nonzero. On success, it will be set to the dispatchers to be received
- // (and assigned handles) as part of the message.
- MojoResult ReadMessage(UserPointer<void> bytes,
- UserPointer<uint32_t> num_bytes,
- DispatcherVector* dispatchers,
- uint32_t* num_dispatchers,
- MojoReadMessageFlags flags);
- MojoResult WriteData(UserPointer<const void> elements,
- UserPointer<uint32_t> elements_num_bytes,
- MojoWriteDataFlags flags);
- MojoResult BeginWriteData(UserPointer<void*> buffer,
- UserPointer<uint32_t> buffer_num_bytes,
- MojoWriteDataFlags flags);
- MojoResult EndWriteData(uint32_t num_bytes_written);
- MojoResult ReadData(UserPointer<void> elements,
- UserPointer<uint32_t> num_bytes,
- MojoReadDataFlags flags);
- MojoResult BeginReadData(UserPointer<const void*> buffer,
- UserPointer<uint32_t> buffer_num_bytes,
- MojoReadDataFlags flags);
- MojoResult EndReadData(uint32_t num_bytes_read);
- // |options| may be null. |new_dispatcher| must not be null, but
- // |*new_dispatcher| should be null (and will contain the dispatcher for the
- // new handle on success).
- MojoResult DuplicateBufferHandle(
- UserPointer<const MojoDuplicateBufferHandleOptions> options,
- scoped_refptr<Dispatcher>* new_dispatcher);
- MojoResult MapBuffer(
- uint64_t offset,
- uint64_t num_bytes,
- MojoMapBufferFlags flags,
- scoped_ptr<embedder::PlatformSharedBufferMapping>* mapping);
-
- // Gets the current handle signals state. (The default implementation simply
- // returns a default-constructed |HandleSignalsState|, i.e., no signals
- // satisfied or satisfiable.) Note: The state is subject to change from other
- // threads.
- HandleSignalsState GetHandleSignalsState() const;
-
- // Adds an awakable to this dispatcher, which will be woken up when this
- // object changes state to satisfy |signals| with context |context|. It will
- // also be woken up when it becomes impossible for the object to ever satisfy
- // |signals| with a suitable error status.
- //
- // If |signals_state| is non-null, on *failure* |*signals_state| will be set
- // to the current handle signals state (on success, it is left untouched).
- //
- // Returns:
- // - |MOJO_RESULT_OK| if the awakable was added;
- // - |MOJO_RESULT_ALREADY_EXISTS| if |signals| is already satisfied;
- // - |MOJO_RESULT_INVALID_ARGUMENT| if the dispatcher has been closed; and
- // - |MOJO_RESULT_FAILED_PRECONDITION| if it is not (or no longer) possible
- // that |signals| will ever be satisfied.
- MojoResult AddAwakable(Awakable* awakable,
- MojoHandleSignals signals,
- uint32_t context,
- HandleSignalsState* signals_state);
- // Removes an awakable from this dispatcher. (It is valid to call this
- // multiple times for the same |awakable| on the same object, so long as
- // |AddAwakable()| was called at most once.) If |signals_state| is non-null,
- // |*signals_state| will be set to the current handle signals state.
- void RemoveAwakable(Awakable* awakable, HandleSignalsState* signals_state);
-
- // A dispatcher must be put into a special state in order to be sent across a
- // message pipe. Outside of tests, only |HandleTableAccess| is allowed to do
- // this, since there are requirements on the handle table (see below).
- //
- // In this special state, only a restricted set of operations is allowed.
- // These are the ones available as |DispatcherTransport| methods. Other
- // |Dispatcher| methods must not be called until |DispatcherTransport::End()|
- // has been called.
- class HandleTableAccess {
- private:
- friend class Core;
- friend class HandleTable;
- // Tests also need this, to avoid needing |Core|.
- friend DispatcherTransport test::DispatcherTryStartTransport(Dispatcher*);
-
- // This must be called under the handle table lock and only if the handle
- // table entry is not marked busy. The caller must maintain a reference to
- // |dispatcher| until |DispatcherTransport::End()| is called.
- static DispatcherTransport TryStartTransport(Dispatcher* dispatcher);
- };
-
- // A |TransportData| may serialize dispatchers that are given to it (and which
- // were previously attached to the |MessageInTransit| that is creating it) to
- // a given |Channel| and then (probably in a different process) deserialize.
- // Note that the |MessageInTransit| "owns" (i.e., has the only ref to) these
- // dispatchers, so there are no locking issues. (There's no lock ordering
- // issue, and in fact no need to take dispatcher locks at all.)
- // TODO(vtl): Consider making another wrapper similar to |DispatcherTransport|
- // (but with an owning, unique reference), and having
- // |CreateEquivalentDispatcherAndCloseImplNoLock()| return that wrapper (and
- // |MessageInTransit|, etc. only holding on to such wrappers).
- class TransportDataAccess {
- private:
- friend class TransportData;
-
- // Serialization API. These functions may only be called on such
- // dispatchers. (|channel| is the |Channel| to which the dispatcher is to be
- // serialized.) See the |Dispatcher| methods of the same names for more
- // details.
- static void StartSerialize(Dispatcher* dispatcher,
- Channel* channel,
- size_t* max_size,
- size_t* max_platform_handles);
- static bool EndSerializeAndClose(
- Dispatcher* dispatcher,
- Channel* channel,
- void* destination,
- size_t* actual_size,
- embedder::PlatformHandleVector* platform_handles);
-
- // Deserialization API.
- // Note: This "clears" (i.e., reset to the invalid handle) any platform
- // handles that it takes ownership of.
- static scoped_refptr<Dispatcher> Deserialize(
- Channel* channel,
- int32_t type,
- const void* source,
- size_t size,
- embedder::PlatformHandleVector* platform_handles);
- };
-
- protected:
- friend class base::RefCountedThreadSafe<Dispatcher>;
-
- Dispatcher();
- virtual ~Dispatcher();
-
- // These are to be overridden by subclasses (if necessary). They are called
- // exactly once -- first |CancelAllAwakablesNoLock()|, then
- // |CloseImplNoLock()|,
- // when the dispatcher is being closed. They are called under |lock_|.
- virtual void CancelAllAwakablesNoLock();
- virtual void CloseImplNoLock();
- virtual scoped_refptr<Dispatcher>
- CreateEquivalentDispatcherAndCloseImplNoLock() = 0;
-
- // These are to be overridden by subclasses (if necessary). They are never
- // called after the dispatcher has been closed. They are called under |lock_|.
- // See the descriptions of the methods without the "ImplNoLock" for more
- // information.
- virtual MojoResult WriteMessageImplNoLock(
- UserPointer<const void> bytes,
- uint32_t num_bytes,
- std::vector<DispatcherTransport>* transports,
- MojoWriteMessageFlags flags);
- virtual MojoResult ReadMessageImplNoLock(UserPointer<void> bytes,
- UserPointer<uint32_t> num_bytes,
- DispatcherVector* dispatchers,
- uint32_t* num_dispatchers,
- MojoReadMessageFlags flags);
- virtual MojoResult WriteDataImplNoLock(UserPointer<const void> elements,
- UserPointer<uint32_t> num_bytes,
- MojoWriteDataFlags flags);
- virtual MojoResult BeginWriteDataImplNoLock(
- UserPointer<void*> buffer,
- UserPointer<uint32_t> buffer_num_bytes,
- MojoWriteDataFlags flags);
- virtual MojoResult EndWriteDataImplNoLock(uint32_t num_bytes_written);
- virtual MojoResult ReadDataImplNoLock(UserPointer<void> elements,
- UserPointer<uint32_t> num_bytes,
- MojoReadDataFlags flags);
- virtual MojoResult BeginReadDataImplNoLock(
- UserPointer<const void*> buffer,
- UserPointer<uint32_t> buffer_num_bytes,
- MojoReadDataFlags flags);
- virtual MojoResult EndReadDataImplNoLock(uint32_t num_bytes_read);
- virtual MojoResult DuplicateBufferHandleImplNoLock(
- UserPointer<const MojoDuplicateBufferHandleOptions> options,
- scoped_refptr<Dispatcher>* new_dispatcher);
- virtual MojoResult MapBufferImplNoLock(
- uint64_t offset,
- uint64_t num_bytes,
- MojoMapBufferFlags flags,
- scoped_ptr<embedder::PlatformSharedBufferMapping>* mapping);
- virtual HandleSignalsState GetHandleSignalsStateImplNoLock() const;
- virtual MojoResult AddAwakableImplNoLock(Awakable* awakable,
- MojoHandleSignals signals,
- uint32_t context,
- HandleSignalsState* signals_state);
- virtual void RemoveAwakableImplNoLock(Awakable* awakable,
- HandleSignalsState* signals_state);
-
- // These implement the API used to serialize dispatchers to a |Channel|
- // (described below). They will only be called on a dispatcher that's attached
- // to and "owned" by a |MessageInTransit|. See the non-"impl" versions for
- // more information.
- //
- // Note: |StartSerializeImplNoLock()| is actually called with |lock_| NOT
- // held, since the dispatcher should only be accessible to the calling thread.
- // On Debug builds, |EndSerializeAndCloseImplNoLock()| is called with |lock_|
- // held, to satisfy any |lock_.AssertAcquired()| (e.g., in |CloseImplNoLock()|
- // -- and anything it calls); disentangling those assertions is
- // difficult/fragile, and would weaken our general checking of invariants.
- //
- // TODO(vtl): Consider making these pure virtual once most things support
- // being passed over a message pipe.
- virtual void StartSerializeImplNoLock(Channel* channel,
- size_t* max_size,
- size_t* max_platform_handles);
- virtual bool EndSerializeAndCloseImplNoLock(
- Channel* channel,
- void* destination,
- size_t* actual_size,
- embedder::PlatformHandleVector* platform_handles);
-
- // Available to subclasses. (Note: Returns a non-const reference, just like
- // |base::AutoLock|'s constructor takes a non-const reference.)
- base::Lock& lock() const { return lock_; }
-
- private:
- friend class DispatcherTransport;
-
- // This should be overridden to return true if/when there's an ongoing
- // operation (e.g., two-phase read/writes on data pipes) that should prevent a
- // handle from being sent over a message pipe (with status "busy").
- virtual bool IsBusyNoLock() const;
-
- // Closes the dispatcher. This must be done under lock, and unlike |Close()|,
- // the dispatcher must not be closed already. (This is the "equivalent" of
- // |CreateEquivalentDispatcherAndCloseNoLock()|, for situations where the
- // dispatcher must be disposed of instead of "transferred".)
- void CloseNoLock();
-
- // Creates an equivalent dispatcher -- representing the same resource as this
- // dispatcher -- and close (i.e., disable) this dispatcher. I.e., this
- // dispatcher will look as though it was closed, but the resource it
- // represents will be assigned to the new dispatcher. This must be called
- // under the dispatcher's lock.
- scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseNoLock();
-
- // API to serialize dispatchers to a |Channel|, exposed to only
- // |TransportData| (via |TransportData|). They may only be called on a
- // dispatcher attached to a |MessageInTransit| (and in particular not in
- // |CoreImpl|'s handle table).
- //
- // Starts the serialization. Returns (via the two "out" parameters) the
- // maximum amount of space that may be needed to serialize this dispatcher to
- // the given |Channel| (no more than
- // |TransportData::kMaxSerializedDispatcherSize|) and the maximum number of
- // |PlatformHandle|s that may need to be attached (no more than
- // |TransportData::kMaxSerializedDispatcherPlatformHandles|). If this
- // dispatcher cannot be serialized to the given |Channel|, |*max_size| and
- // |*max_platform_handles| should be set to zero. A call to this method will
- // ALWAYS be followed by a call to |EndSerializeAndClose()| (even if this
- // dispatcher cannot be serialized to the given |Channel|).
- void StartSerialize(Channel* channel,
- size_t* max_size,
- size_t* max_platform_handles);
- // Completes the serialization of this dispatcher to the given |Channel| and
- // closes it. (This call will always follow an earlier call to
- // |StartSerialize()|, with the same |Channel|.) This does so by writing to
- // |destination| and appending any |PlatformHandle|s needed to
- // |platform_handles| (which may be null if no platform handles were indicated
- // to be required to |StartSerialize()|). This may write no more than the
- // amount indicated by |StartSerialize()|. (WARNING: Beware of races, e.g., if
- // something can be mutated between the two calls!) Returns true on success,
- // in which case |*actual_size| is set to the amount it actually wrote to
- // |destination|. On failure, |*actual_size| should not be modified; however,
- // the dispatcher will still be closed.
- bool EndSerializeAndClose(Channel* channel,
- void* destination,
- size_t* actual_size,
- embedder::PlatformHandleVector* platform_handles);
-
- // This protects the following members as well as any state added by
- // subclasses.
- mutable base::Lock lock_;
- bool is_closed_;
-
- DISALLOW_COPY_AND_ASSIGN(Dispatcher);
-};
-
-// Wrapper around a |Dispatcher| pointer, while it's being processed to be
-// passed in a message pipe. See the comment about
-// |Dispatcher::HandleTableAccess| for more details.
-//
-// Note: This class is deliberately "thin" -- no more expensive than a
-// |Dispatcher*|.
-class MOJO_SYSTEM_IMPL_EXPORT DispatcherTransport {
- public:
- DispatcherTransport() : dispatcher_(nullptr) {}
-
- void End();
-
- Dispatcher::Type GetType() const { return dispatcher_->GetType(); }
- bool IsBusy() const { return dispatcher_->IsBusyNoLock(); }
- void Close() { dispatcher_->CloseNoLock(); }
- scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndClose() {
- return dispatcher_->CreateEquivalentDispatcherAndCloseNoLock();
- }
-
- bool is_valid() const { return !!dispatcher_; }
-
- protected:
- Dispatcher* dispatcher() { return dispatcher_; }
-
- private:
- friend class Dispatcher::HandleTableAccess;
-
- explicit DispatcherTransport(Dispatcher* dispatcher)
- : dispatcher_(dispatcher) {}
-
- Dispatcher* dispatcher_;
-
- // Copy and assign allowed.
-};
-
-} // namespace system
-} // namespace mojo
-
-#endif // MOJO_EDK_SYSTEM_DISPATCHER_H_
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