/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 HeapSnapshot represents a snapshot of the heap graph
*/
[ChromeOnly, Exposed=(Window,Worker)]
interface HeapSnapshot {
/**
* A time stamp of when the heap snapshot was taken, if available. Units are
* microseconds since midnight (00:00:00) 1 January 1970 UTC.
*/
readonly attribute unsigned long long? creationTime;
/**
* Take a census of the heap snapshot.
*
* This is the same as |Debugger.Memory.prototype.takeCensus|, but operates on
* the offline heap snapshot's serialized heap graph rather than the live heap
* graph. The same optional configuration options that can be passed to that
* function can be passed here.
*
* The returned value is determined by the `"breakdown"` option used, and is
* usually a `Map`, `Object`, or `Array`. For example, the following breakdown
*
* {
* by: "coarseType",
* objects: { by: "objectClass" },
* other: { by: "internalType" }
* }
*
* produces a result like this:
*
* {
* "objects": {
* "Function": { "count": 404, "bytes": 37328 },
* "Object": { "count": 11, "bytes": 1264 },
* "Debugger": { "count": 1, "bytes": 416 },
* "ScriptSource": { "count": 1, "bytes": 64 },
* // ... omitted for brevity...
* },
* "scripts": { "count": 1, "bytes": 0 },
* "strings": { "count": 701, "bytes": 49080 },
* "other": {
* "js::Shape": { "count": 450, "bytes": 0 },
* "js::BaseShape": { "count": 21, "bytes": 0 },
* "js::ObjectGroup": { "count": 17, "bytes": 0 }
* }
* }
*
* See the `takeCensus` section of the `js/src/doc/Debugger/Debugger.Memory.md`
* file for detailed documentation.
*/
[Throws]
any takeCensus(object? options);
/**
* Describe `node` with the specified `breakdown`. See the comment above
* `takeCensus` or `js/src/doc/Debugger/Debugger.Memory.md` for detailed
* documentation on breakdowns.
*
* Throws an error when `node` is not the id of a node in the heap snapshot,
* or if the breakdown is invalid.
*/
[Throws]
any describeNode(object breakdown, NodeId node);
/**
* Compute the dominator tree for this heap snapshot.
*
* @see DominatorTree.webidl
*/
[Throws]
DominatorTree computeDominatorTree();
/**
* Find the shortest retaining paths from the node associated with the ID
* `start` to each node associated with the IDs in `targets`. Find at most
* `maxNumPaths` retaining paths for each target node.
*
* The return value is a Map object mapping from each target node ID to an
* array of retaining paths. The array may be empty if we did not find any
* retaining paths.
*
* A path is an array of objects of the form:
*
* {
* predecessor: <node ID>,
* edge: <string or null>,
* }
*
* The first `predecessor` will always be `start`. The last edge in the path
* leads to the `target` node that is mapped to the path; the `target` does
* not appear as a `predecessor` in the path.
*
* Throws when `start` or any of the elements of `targets` are not an ID of a
* node in the snapshot, or if we encounter an out of memory exception.
*/
[Throws]
object computeShortestPaths(NodeId start, sequence<NodeId> targets,
unsigned long long maxNumPaths);
};
