/* 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/. */
[ptr] native FILE(FILE);
[ptr] native nsCycleCollectorLoggerPtr(nsCycleCollectorLogger);
* A set of interfaces for recording the cycle collector's work. An instance
* of nsICycleCollectorListener can be configured to enable various
* options, then passed to the cycle collector when it runs.
* Note that additional logging options are available by setting environment
* variables, as described at the top of nsCycleCollector.cpp.
* nsICycleCollectorHandler is the interface JS code should implement to
* receive the results logged by an nsICycleCollectorListener
* instance. Pass an instance of this to the logger's 'processNext' method
* after the collection has run. This will describe the objects the cycle
* collector visited, the edges it found, and the conclusions it reached
* about the liveness of objects.
* In more detail:
* - For each node in the graph:
* - a call is made to either |noteRefCountedObject| or |noteGCedObject|, to
* describe the node itself; and
* - for each edge starting at that node, a call is made to |noteEdge|.
* - Then, a series of calls are made to:
* - |describeRoot|, for reference-counted nodes that the CC has identified as
* being alive because there are unknown references to those nodes.
* - |describeGarbage|, for nodes the cycle collector has identified as garbage.
* Any node not mentioned in a call to |describeRoot| or |describeGarbage| is
* neither a root nor garbage. The cycle collector was able to find all of the
* edges implied by the node's reference count.
interface nsICycleCollectorHandler : nsISupports
void noteRefCountedObject(in ACString aAddress,
in unsigned long aRefCount,
in ACString aObjectDescription);
void noteGCedObject(in ACString aAddress,
in boolean aMarked,
in ACString aObjectDescription,
in ACString aCompartmentAddress);
void noteEdge(in ACString aFromAddress,
in ACString aToAddress,
in ACString aEdgeName);
void describeRoot(in ACString aAddress,
in unsigned long aKnownEdges);
void describeGarbage(in ACString aAddress);
* This interface allows replacing the log-writing backend for an
* nsICycleCollectorListener. As this interface is also called while
* the cycle collector is running, it cannot be implemented in JS.
[scriptable, builtinclass, uuid(3ad9875f-d0e4-4ac2-87e3-f127f6c02ce1)]
interface nsICycleCollectorLogSink : nsISupports
[noscript] void open(out FILE aGCLog, out FILE aCCLog);
// This string will appear somewhere in the log's filename.
attribute AString filenameIdentifier;
// This is the process ID; it can be changed if logging is on behalf
// of another process.
attribute int32_t processIdentifier;
// The GC log file, if logging to files.
readonly attribute nsIFile gcLog;
// The CC log file, if logging to files.
readonly attribute nsIFile ccLog;
* This interface is used to configure some reporting options for the cycle
* is called while the cycle collector is running.
* To analyze cycle collection data in JS:
* - Create an instance of nsICycleCollectorListener, which implements this
* interface. In C++, this can be done by calling
* nsCycleCollector_createLogger(). In JS, this can be done by calling
* - Set its |disableLog| property to true. This prevents the logger from
* printing messages about each method call to a temporary log file.
* - Set its |wantAfterProcessing| property to true. This tells the logger
* to record calls to its methods in memory. The |processNext| method
* returns events from this record.
* - Perform a collection using the logger. For example, call
* |nsIDOMWindowUtils|'s |garbageCollect| method, passing the logger as
* the |aListener| argument.
* - When the collection is complete, loop calling the logger's
* nsICycleCollectorHandler. This JS code is free to allocate and operate
* on objects however it pleases: the cycle collector has finished its
* work, and the JS code is simply consuming recorded data.
[scriptable, builtinclass, uuid(703b53b6-24f6-40c6-9ea9-aeb2dc53d170)]
interface nsICycleCollectorListener : nsISupports
// Return a listener that directs the cycle collector to traverse
// objects that it knows won't be collectable.
// Note that even this listener will not visit every node in the heap;
// the cycle collector can't see the entire heap. But while this
// listener is in use, the collector disables some optimizations it
// normally uses to avoid certain classes of objects that are certainly
// alive. So, if your purpose is to get a view of the portion of the
// heap that is of interest to the cycle collector, and not simply find
// garbage, then you should use the listener this returns.
// Note that this does not necessarily return a new listener; rather, it may
// simply set a flag on this listener (a side effect!) and return it.
// True if this listener will behave like one returned by allTraces().
readonly attribute boolean wantAllTraces;
// If true, do not log each method call to a temporary file.
// Initially false.
attribute boolean disableLog;
// If |disableLog| is false, this object will be sent the log text.
attribute nsICycleCollectorLogSink logSink;
// If true, record all method calls in memory, to be retrieved later
// using |processNext|. Initially false.
attribute boolean wantAfterProcessing;
// Report the next recorded event to |aHandler|, and remove it from the
// record. Return false if there isn't anything more to process.
// Note that we only record events to report here if our
// |wantAfterProcessing| property is true.
boolean processNext(in nsICycleCollectorHandler aHandler);
// Return the current object as an nsCycleCollectorLogger*, which is the
// only class that should be implementing this interface. We need the
// concrete implementation type to help the GC rooting analysis.
[noscript] nsCycleCollectorLoggerPtr asLogger();