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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/. */
"use strict";
const { Task } = require("devtools/shared/task");
const EventEmitter = require("devtools/shared/event-emitter");
const { LocationStore, serialize, deserialize } = require("./location-store");
/**
* A manager class that wraps a TabTarget and listens to source changes
* from source maps and resolves non-source mapped locations to the source mapped
* versions and back and forth, and creating smart elements with a location that
* auto-update when the source changes (from pretty printing, source maps loading, etc)
*
* @param {TabTarget} target
*/
function SourceMapService(target) {
this._target = target;
this._locationStore = new LocationStore();
this._isNotSourceMapped = new Map();
EventEmitter.decorate(this);
this._onSourceUpdated = this._onSourceUpdated.bind(this);
this._resolveLocation = this._resolveLocation.bind(this);
this._resolveAndUpdate = this._resolveAndUpdate.bind(this);
this.subscribe = this.subscribe.bind(this);
this.unsubscribe = this.unsubscribe.bind(this);
this.reset = this.reset.bind(this);
this.destroy = this.destroy.bind(this);
target.on("source-updated", this._onSourceUpdated);
target.on("navigate", this.reset);
target.on("will-navigate", this.reset);
}
/**
* Clears the store containing the cached promised locations
*/
SourceMapService.prototype.reset = function () {
// Guard to prevent clearing the store when it is not initialized yet.
if (!this._locationStore) {
return;
}
this._locationStore.clear();
this._isNotSourceMapped.clear();
};
SourceMapService.prototype.destroy = function () {
this.reset();
this._target.off("source-updated", this._onSourceUpdated);
this._target.off("navigate", this.reset);
this._target.off("will-navigate", this.reset);
this._target.off("close", this.destroy);
this._target = this._locationStore = this._isNotSourceMapped = null;
};
/**
* Sets up listener for the callback to update the FrameView
* and tries to resolve location, if it is source-mappable
* @param location
* @param callback
*/
SourceMapService.prototype.subscribe = function (location, callback) {
// A valid candidate location for source-mapping should have a url and line.
// Abort if there's no `url`, which means it's unsourcemappable anyway,
// like an eval script.
// From previous attempts to source-map locations, we also determine if a location
// is not source-mapped.
if (!location.url || !location.line || this._isNotSourceMapped.get(location.url)) {
return;
}
this.on(serialize(location), callback);
this._locationStore.set(location);
this._resolveAndUpdate(location);
};
/**
* Removes the listener for the location and clears cached locations
* @param location
* @param callback
*/
SourceMapService.prototype.unsubscribe = function (location, callback) {
this.off(serialize(location), callback);
// Check to see if the store exists before attempting to clear a location
// Sometimes un-subscribe happens during the destruction cascades and this
// condition is to protect against that. Could be looked into in the future.
if (!this._locationStore) {
return;
}
this._locationStore.clearByURL(location.url);
};
/**
* Tries to resolve the location and if successful,
* emits the resolved location
* @param location
* @private
*/
SourceMapService.prototype._resolveAndUpdate = function (location) {
this._resolveLocation(location).then(resolvedLocation => {
// We try to source map the first console log to initiate the source-updated
// event from target. The isSameLocation check is to make sure we don't update
// the frame, if the location is not source-mapped.
if (resolvedLocation && !isSameLocation(location, resolvedLocation)) {
this.emit(serialize(location), location, resolvedLocation);
}
});
};
/**
* Checks if there is existing promise to resolve location, if so returns cached promise
* if not, tries to resolve location and returns a promised location
* @param location
* @return Promise<Object>
* @private
*/
SourceMapService.prototype._resolveLocation = Task.async(function* (location) {
let resolvedLocation;
const cachedLocation = this._locationStore.get(location);
if (cachedLocation) {
resolvedLocation = cachedLocation;
} else {
const promisedLocation = resolveLocation(this._target, location);
if (promisedLocation) {
this._locationStore.set(location, promisedLocation);
resolvedLocation = promisedLocation;
}
}
return resolvedLocation;
});
/**
* Checks if the `source-updated` event is fired from the target.
* Checks to see if location store has the source url in its cache,
* if so, tries to update each stale location in the store.
* Determines if the source should be source-mapped or not.
* @param _
* @param sourceEvent
* @private
*/
SourceMapService.prototype._onSourceUpdated = function (_, sourceEvent) {
let { type, source } = sourceEvent;
// If we get a new source, and it's not a source map, abort;
// we can have no actionable updates as this is just a new normal source.
// Check Source Actor for sourceMapURL property (after Firefox 48)
// If not present, utilize isSourceMapped and isPrettyPrinted properties
// to estimate if a source is not source-mapped.
const isNotSourceMapped = !(source.sourceMapURL ||
source.isSourceMapped || source.isPrettyPrinted);
if (type === "newSource" && isNotSourceMapped) {
this._isNotSourceMapped.set(source.url, true);
return;
}
let sourceUrl = null;
if (source.generatedUrl && source.isSourceMapped) {
sourceUrl = source.generatedUrl;
} else if (source.url && source.isPrettyPrinted) {
sourceUrl = source.url;
}
const locationsToResolve = this._locationStore.getByURL(sourceUrl);
if (locationsToResolve.length) {
this._locationStore.clearByURL(sourceUrl);
for (let location of locationsToResolve) {
this._resolveAndUpdate(deserialize(location));
}
}
};
exports.SourceMapService = SourceMapService;
/**
* Take a TabTarget and a location, containing a `url`, `line`, and `column`, resolve
* the location to the latest location (so a source mapped location, or if pretty print
* status has been updated)
*
* @param {TabTarget} target
* @param {Object} location
* @return {Promise<Object>}
*/
function resolveLocation(target, location) {
return Task.spawn(function* () {
let newLocation = yield target.resolveLocation({
url: location.url,
line: location.line,
column: location.column || Infinity
});
// Source or mapping not found, so don't do anything
if (newLocation.error) {
return null;
}
return newLocation;
});
}
/**
* Returns true if the original location and resolved location are the same
* @param location
* @param resolvedLocation
* @returns {boolean}
*/
function isSameLocation(location, resolvedLocation) {
return location.url === resolvedLocation.url &&
location.line === resolvedLocation.line &&
location.column === resolvedLocation.column;
}
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