2016-12-02 02:28:54 +03:00
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_a11y_IPCTypes_h
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#define mozilla_a11y_IPCTypes_h
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/**
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* Since IPDL does not support preprocessing, this header file allows us to
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* define types used by PDocAccessible differently depending on platform.
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*/
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#if defined(XP_WIN) && defined(ACCESSIBILITY)
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// So that we don't include a bunch of other Windows junk.
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#if !defined(COM_NO_WINDOWS_H)
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#define COM_NO_WINDOWS_H
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#endif // !defined(COM_NO_WINDOWS_H)
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// COM headers pull in MSXML which conflicts with our own XMLDocument class.
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// This define excludes those conflicting definitions.
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#if !defined(__XMLDocument_FWD_DEFINED__)
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#define __XMLDocument_FWD_DEFINED__
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#endif // !defined(__XMLDocument_FWD_DEFINED__)
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Bug 1303060: Changes to a11y to enable the serving of a COM handler; r=tbsaunde
MozReview-Commit-ID: GTQF3x1pBtX
A general outline of the COM handler (a.k.a. the "smart proxy"):
COM handlers are pieces of code that are loaded by the COM runtime along with
a proxy and are layered above that proxy. This enables the COM handler to
interpose itself between the caller and the proxy, thus providing the
opportunity for the handler to manipulate an interface's method calls before
those calls reach the proxy.
Handlers are regular COM components that live in DLLs and are declared in the
Windows registry. In order to allow for the specifying of a handler (and an
optional payload to be sent with the proxy), the mscom library allows its
clients to specify an implementation of the IHandlerProvider interface.
IHandlerProvider consists of 5 functions:
* GetHandler returns the CLSID of the component that should be loaded into
the COM client's process. If GetHandler returns a failure code, then no
handler is loaded.
* GetHandlerPayloadSize and WriteHandlerPayload are for obtaining the payload
data. These calls are made on a background thread but need to do their work
on the main thread. We declare the payload struct in IDL. MIDL generates two
functions, IA2Payload_Encode and IA2Payload_Decode, which are used by
mscom::StructToStream to read and write that struct to and from buffers.
* The a11y payload struct also includes an interface, IGeckoBackChannel, that
allows the handler to communicate directly with Gecko. IGeckoBackChannel
currently provides two methods: one to allow the handler to request fresh
cache information, and the other to provide Gecko with its IHandlerControl
interface.
* MarshalAs accepts an IID that specifies the interface that is about to be
proxied. We may want to send a more sophisticated proxy than the one that
is requested. The desired IID is returned by this function. In the case of
a11y interfaces, we should always return IAccessible2_3 if we are asked for
one of its parent interfaces. This allows us to eliminate round trips to
resolve more sophisticated interfaces later on.
* NewInstance, which is needed to ensure that all descendent proxies are also
imbued with the same handler code.
The main focus of this patch is as follows:
1. Provide an implementation of the IHandlerProvider interface;
2. Populate the handler payload (ie, the cache) with data;
3. Modify CreateHolderFromAccessible to specify the HandlerPayload object;
4. Receive the IHandlerControl interface from the handler DLL and move it
into the chrome process.
Some more information about IHandlerControl:
There is one IHandlerControl per handler DLL instance. It is the interface that
we call in Gecko when we need to dispatch an event to the handler. In order to
ensure that events are dispatched in the correct order, we need to dispatch
those events from the chrome main thread so that they occur in sequential order
with calls to NotifyWinEvent.
--HG--
extra : rebase_source : acb44dead7cc5488424720e1bf58862b7b30374f
2017-04-05 00:23:55 +03:00
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#include <combaseapi.h>
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2016-12-02 02:28:54 +03:00
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#include "mozilla/a11y/COMPtrTypes.h"
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// This define in rpcndr.h messes up our code, so we must undefine it after
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// COMPtrTypes.h has been included.
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#if defined(small)
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#undef small
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#endif // defined(small)
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#else
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namespace mozilla {
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namespace a11y {
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typedef uint32_t IAccessibleHolder;
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Bug 1303060: Changes to a11y to enable the serving of a COM handler; r=tbsaunde
MozReview-Commit-ID: GTQF3x1pBtX
A general outline of the COM handler (a.k.a. the "smart proxy"):
COM handlers are pieces of code that are loaded by the COM runtime along with
a proxy and are layered above that proxy. This enables the COM handler to
interpose itself between the caller and the proxy, thus providing the
opportunity for the handler to manipulate an interface's method calls before
those calls reach the proxy.
Handlers are regular COM components that live in DLLs and are declared in the
Windows registry. In order to allow for the specifying of a handler (and an
optional payload to be sent with the proxy), the mscom library allows its
clients to specify an implementation of the IHandlerProvider interface.
IHandlerProvider consists of 5 functions:
* GetHandler returns the CLSID of the component that should be loaded into
the COM client's process. If GetHandler returns a failure code, then no
handler is loaded.
* GetHandlerPayloadSize and WriteHandlerPayload are for obtaining the payload
data. These calls are made on a background thread but need to do their work
on the main thread. We declare the payload struct in IDL. MIDL generates two
functions, IA2Payload_Encode and IA2Payload_Decode, which are used by
mscom::StructToStream to read and write that struct to and from buffers.
* The a11y payload struct also includes an interface, IGeckoBackChannel, that
allows the handler to communicate directly with Gecko. IGeckoBackChannel
currently provides two methods: one to allow the handler to request fresh
cache information, and the other to provide Gecko with its IHandlerControl
interface.
* MarshalAs accepts an IID that specifies the interface that is about to be
proxied. We may want to send a more sophisticated proxy than the one that
is requested. The desired IID is returned by this function. In the case of
a11y interfaces, we should always return IAccessible2_3 if we are asked for
one of its parent interfaces. This allows us to eliminate round trips to
resolve more sophisticated interfaces later on.
* NewInstance, which is needed to ensure that all descendent proxies are also
imbued with the same handler code.
The main focus of this patch is as follows:
1. Provide an implementation of the IHandlerProvider interface;
2. Populate the handler payload (ie, the cache) with data;
3. Modify CreateHolderFromAccessible to specify the HandlerPayload object;
4. Receive the IHandlerControl interface from the handler DLL and move it
into the chrome process.
Some more information about IHandlerControl:
There is one IHandlerControl per handler DLL instance. It is the interface that
we call in Gecko when we need to dispatch an event to the handler. In order to
ensure that events are dispatched in the correct order, we need to dispatch
those events from the chrome main thread so that they occur in sequential order
with calls to NotifyWinEvent.
--HG--
extra : rebase_source : acb44dead7cc5488424720e1bf58862b7b30374f
2017-04-05 00:23:55 +03:00
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typedef uint32_t IHandlerControlHolder;
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2016-12-02 02:28:54 +03:00
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} // namespace a11y
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} // namespace mozilla
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#endif // defined(XP_WIN) && defined(ACCESSIBILITY)
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#endif // mozilla_a11y_IPCTypes_h
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