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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* A mechanism for specifying shutdown dependencies between
* asynchronous services.
*
* Note that this XPCOM component is designed primarily for C++
* clients. JavaScript clients should rather use AsyncShutdown.sys.mjs,
* which provides a better API and better error reporting for them.
*/
#include "nsISupports.idl"
#include "nsIPropertyBag.idl"
#include "nsIVariant.idl"
interface nsIAsyncShutdownClient;
/**
* A blocker installed by a client to be informed during some stage of
* shutdown and block shutdown asynchronously until some condition is
* complete.
*
* If you wish to use AsyncShutdown, you will need to implement this
* interface (and only this interface).
*/
[scriptable, uuid(4ef43f29-6715-4b57-a750-2ff83695ddce)]
interface nsIAsyncShutdownBlocker: nsISupports {
/**
* The *unique* name of the blocker.
*
* By convention, it should respect the following format:
* "MyModuleName: Doing something while it's time"
* e.g.
* "OS.File: Flushing before profile-before-change"
*
* This attribute is uploaded as part of crash reports.
*/
readonly attribute AString name;
/**
* Inform the blocker that the stage of shutdown has started.
* Shutdown will NOT proceed until `aBarrierClient.removeBlocker(this)`
* has been called.
*/
void blockShutdown(in nsIAsyncShutdownClient aBarrierClient);
/**
* The current state of the blocker.
*
* In case of crash, this is converted to JSON and attached to
* the crash report.
*
* This field may be used to provide JSON-style data structures.
* For this purpose, use
* - nsIPropertyBag to represent objects;
* - nsIVariant to represent field values (which may hold nsIPropertyBag
* themselves).
*/
readonly attribute nsIPropertyBag state;
};
/**
* A client for a nsIAsyncShutdownBarrier.
*/
[scriptable, uuid(d2031049-b990-43a2-95be-59f8a3ca5954)]
interface nsIAsyncShutdownClient: nsISupports {
/**
* The name of the barrier.
*/
readonly attribute AString name;
/**
* Whether the client is still open for new blockers.
* When this is true it is too late to add new blockers and addBlocker will
* throw an exception.
*/
readonly attribute boolean isClosed;
/**
* Add a blocker.
*
* After a `blocker` has been added with `addBlocker`, if it is not
* removed with `removeBlocker`, this will, by design, eventually
* CAUSE A CRASH.
*
* Calling `addBlocker` once nsIAsyncShutdownBarrier::wait() has been
* called on the owning barrier returns an error.
*
* @param aBlocker The blocker to add. Once
* nsIAsyncShutdownBarrier::wait() has been called, it will not
* call its `aOnReady` callback until all blockers have been
* removed, each by a call to `removeBlocker`.
* @param aFileName The filename of the callsite, as given by `__FILE__`.
* @param aLineNumber The linenumber of the callsite, as given by `__LINE__`.
* @param aStack Information on the stack that lead to this call. Generally
* empty when called from C++.
* @throws If it's too late to add a blocker.
* @see isClosed.
*/
void addBlocker(in nsIAsyncShutdownBlocker aBlocker,
in AString aFileName,
in long aLineNumber,
in AString aStack);
/**
* Remove a blocker.
*
* @param aBlocker A blocker previously added to this client through
* `addBlocker`. Noop if the blocker has never been added or has been
* removed already.
*/
void removeBlocker(in nsIAsyncShutdownBlocker aBlocker);
/**
* The JS implementation of the client.
*
* It is strongly recommended that JS clients of this API use
* `jsclient` instead of the `nsIAsyncShutdownClient`. See
* AsyncShutdown.sys.mjs for more information on the JS version of
* this API.
*/
readonly attribute jsval jsclient;
};
/**
* Callback invoked once all blockers of a barrier have been removed.
*/
[scriptable, function, uuid(910c9309-1da0-4dd0-8bdb-a325a38c604e)]
interface nsIAsyncShutdownCompletionCallback: nsISupports {
/**
* The operation has been completed.
*/
void done();
};
/**
* A stage of shutdown that supports blocker registration.
*/
[scriptable, uuid(50fa8a86-9c91-4256-8389-17d310adec90)]
interface nsIAsyncShutdownBarrier: nsISupports {
/**
* The blocker registration capability. Most services may wish to
* publish this capability to let services that depend on it register
* blockers.
*/
readonly attribute nsIAsyncShutdownClient client;
/**
* The state of all the blockers of the barrier.
*
* See the documentation of `nsIAsyncShutdownBlocker` for the
* format.
*/
readonly attribute nsIPropertyBag state;
/**
* Wait for all blockers to complete.
*
* Method `aOnReady` will be called once all blockers have finished.
* The callback always receives NS_OK.
*/
void wait(in nsIAsyncShutdownCompletionCallback aOnReady);
};
/**
* A service that allows registering shutdown-time dependencies.
*/
[scriptable, uuid(db365c78-c860-4e64-9a63-25b73f89a016)]
interface nsIAsyncShutdownService: nsISupports {
/**
* Create a new barrier.
*
* By convention, the name should respect the following format:
* "MyModuleName: Doing something while it's time"
* e.g.
* "OS.File: Waiting for clients to flush before shutting down"
*
* This attribute is uploaded as part of crash reports.
*/
nsIAsyncShutdownBarrier makeBarrier(in AString aName);
// Barriers for global shutdown stages in the parent process.
/**
* Barrier for notification profile-before-change.
*/
readonly attribute nsIAsyncShutdownClient profileBeforeChange;
/**
* Barrier for notification profile-change-teardown.
*/
readonly attribute nsIAsyncShutdownClient profileChangeTeardown;
/**
* Barrier for notification quit-application-granted.
*/
readonly attribute nsIAsyncShutdownClient quitApplicationGranted;
/**
* Barrier for notification profile-before-change-telemetry.
*/
readonly attribute nsIAsyncShutdownClient sendTelemetry;
// Barriers for global shutdown stages in all processes.
/**
* Barrier for notification web-workers-shutdown.
*/
readonly attribute nsIAsyncShutdownClient webWorkersShutdown;
/**
* Barrier for notification xpcom-will-shutdown.
*/
readonly attribute nsIAsyncShutdownClient xpcomWillShutdown;
// Don't add a barrier for content-child-shutdown because this
// makes it easier to cause shutdown hangs.
};
%{C++
#define NS_ASYNCSHUTDOWNSERVICE_CONTRACTID "@mozilla.org/async-shutdown-service;1"
%}
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