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DevTools: improve identifier extraction in SourceMapNamesResolver
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Apart from extracting identifier names from SourceMap.name entries,
this patch attempts to extract variable names from a mapped source.

BUG=none
R=dgozman, pfeldman_ooo

Review URL: https://codereview.chromium.org/1887913002

Cr-Commit-Position: refs/heads/master@{#387533}
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@aslushnikov
aslushnikov authored and Commit bot committed Apr 15, 2016
1 parent e2ca0ad commit decf4d4
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Showing 6 changed files with 180 additions and 64 deletions.
10 changes: 10 additions & 0 deletions front_end/common/Text.js
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Original file line number Diff line number Diff line change
Expand Up @@ -128,6 +128,16 @@ WebInspector.TextCursor.prototype = {
return this._offset;
},

/**
* @param {number} offset
*/
resetTo: function(offset)
{
this._offset = offset;
this._lineNumber = this._lineEndings.lowerBound(offset);
this._columnNumber = this._lineNumber ? this._offset - this._lineEndings[this._lineNumber - 1] - 1 : this._offset;
},

/**
* @return {number}
*/
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11 changes: 8 additions & 3 deletions front_end/es_tree/ESTreeWalker.js
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Original file line number Diff line number Diff line change
Expand Up @@ -5,14 +5,16 @@
/**
* @constructor
* @param {function(!ESTree.Node)} beforeVisit
* @param {function(!ESTree.Node)} afterVisit
* @param {function(!ESTree.Node)=} afterVisit
*/
WebInspector.ESTreeWalker = function(beforeVisit, afterVisit)
{
this._beforeVisit = beforeVisit;
this._afterVisit = afterVisit;
this._afterVisit = afterVisit || new Function();
}

WebInspector.ESTreeWalker.SkipSubtree = {};

WebInspector.ESTreeWalker.prototype = {
/**
* @param {!ESTree.Node} ast
Expand All @@ -32,7 +34,10 @@ WebInspector.ESTreeWalker.prototype = {
return;
node.parent = parent;

this._beforeVisit.call(null, node);
if (this._beforeVisit.call(null, node) === WebInspector.ESTreeWalker.SkipSubtree) {
this._afterVisit.call(null, node);
return;
}

var walkOrder = WebInspector.ESTreeWalker._walkOrder[node.type];
if (!walkOrder) {
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2 changes: 2 additions & 0 deletions front_end/externs.js
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Original file line number Diff line number Diff line change
Expand Up @@ -683,6 +683,8 @@ ESTree.Node = function()
this.name;
/** @type {(?ESTree.Node|undefined)} */
this.id;
/** @type {(number|undefined)} */
this.length;
}

/**
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40 changes: 20 additions & 20 deletions front_end/formatter_worker/FormatterWorker.js
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Original file line number Diff line number Diff line change
Expand Up @@ -131,49 +131,49 @@ WebInspector.evaluatableJavaScriptSubstring = function(content)
*/
WebInspector.javaScriptIdentifiers = function(content)
{
var root = acorn.parse(content, {});
var root = acorn.parse(content, { ranges: false, ecmaVersion: 6 });

/** @type {!Array<!ESTree.Node>} */
var identifiers = [];
var functionDeclarationCounter = 0;
var walker = new WebInspector.ESTreeWalker(beforeVisit, afterVisit);
var walker = new WebInspector.ESTreeWalker(beforeVisit);

/**
* @param {!ESTree.Node} node
* @return {boolean}
*/
function isFunction(node)
{
return node.type === "FunctionDeclaration" || node.type === "FunctionExpression";
return node.type === "FunctionDeclaration" || node.type === "FunctionExpression" || node.type === "ArrowFunctionExpression";
}

/**
* @param {!ESTree.Node} node
*/
function beforeVisit(node)
{
if (isFunction(node))
functionDeclarationCounter++;
if (isFunction(node)) {
if (node.id)
identifiers.push(node.id);
return WebInspector.ESTreeWalker.SkipSubtree;
}

if (functionDeclarationCounter > 1)
if (node.type !== "Identifier")
return;

if (isFunction(node) && node.params)
identifiers.pushAll(node.params);

if (node.type === "VariableDeclarator")
identifiers.push(/** @type {!ESTree.Node} */(node.id));
if (node.parent && node.parent.type === "MemberExpression" && node.parent.property === node && !node.parent.computed)
return;
identifiers.push(node);
}

/**
* @param {!ESTree.Node} node
*/
function afterVisit(node)
{
if (isFunction(node))
functionDeclarationCounter--;
if (!root || root.type !== "Program" || root.body.length !== 1 || !isFunction(root.body[0])) {
postMessage([]);
return;
}

walker.walk(root);
var functionNode = root.body[0];
for (var param of functionNode.params)
walker.walk(param);
walker.walk(functionNode.body);
var reduced = identifiers.map(id => ({name: id.name, offset: id.start}));
postMessage(reduced);
}
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9 changes: 8 additions & 1 deletion front_end/sdk/DebuggerModel.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1038,7 +1038,6 @@ WebInspector.DebuggerModel.CallFrame.fromPayloadArray = function(debuggerModel,
}

WebInspector.DebuggerModel.CallFrame.prototype = {

/**
* @return {!WebInspector.Script}
*/
Expand Down Expand Up @@ -1205,6 +1204,14 @@ WebInspector.DebuggerModel.Scope = function(callFrame, ordinal)
}

WebInspector.DebuggerModel.Scope.prototype = {
/**
* @return {!WebInspector.DebuggerModel.CallFrame}
*/
callFrame: function()
{
return this._callFrame;
},

/**
* @return {string}
*/
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172 changes: 132 additions & 40 deletions front_end/sources/SourceMapNamesResolver.js
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Original file line number Diff line number Diff line change
Expand Up @@ -5,53 +5,49 @@
WebInspector.SourceMapNamesResolver = {};

WebInspector.SourceMapNamesResolver._cachedMapSymbol = Symbol("cache");
WebInspector.SourceMapNamesResolver._cachedPromiseSymbol = Symbol("cachePromise");
WebInspector.SourceMapNamesResolver._cachedIdentifiersSymbol = Symbol("cachedIdentifiers");

/**
* @param {!WebInspector.DebuggerModel.Scope} scope
* @return {!Promise.<!Map<string, string>>}
* @constructor
* @param {string} name
* @param {number} lineNumber
* @param {number} columnNumber
*/
WebInspector.SourceMapNamesResolver._resolveScope = function(scope)
WebInspector.SourceMapNamesResolver.Identifier = function(name, lineNumber, columnNumber)
{
var cachedMap = scope[WebInspector.SourceMapNamesResolver._cachedMapSymbol];
if (cachedMap)
return Promise.resolve(cachedMap);

var cachedPromise = scope[WebInspector.SourceMapNamesResolver._cachedPromiseSymbol];
if (cachedPromise)
return cachedPromise;
this.name = name;
this.lineNumber = lineNumber;
this.columnNumber = columnNumber;
}

/**
* @param {!WebInspector.DebuggerModel.Scope} scope
* @return {!Promise<!Array<!WebInspector.SourceMapNamesResolver.Identifier>>}
*/
WebInspector.SourceMapNamesResolver._scopeIdentifiers = function(scope)
{
var startLocation = scope.startLocation();
var endLocation = scope.endLocation();

if (scope.type() === DebuggerAgent.ScopeType.Global || !startLocation || !endLocation || !startLocation.script().sourceMapURL || (startLocation.script() !== endLocation.script()))
return Promise.resolve(new Map());
return Promise.resolve(/** @type {!Array<!WebInspector.SourceMapNamesResolver.Identifier>}*/([]));

var script = startLocation.script();
var sourceMap = WebInspector.debuggerWorkspaceBinding.sourceMapForScript(script);
if (!sourceMap)
return Promise.resolve(new Map());

var promise = script.requestContent().then(onContent);
scope[WebInspector.SourceMapNamesResolver._cachedPromiseSymbol] = promise;
return promise;
return script.requestContent().then(onContent);

/**
* @param {?string} content
* @return {!Promise<!Map<string, string>>}
* @return {!Promise<!Array<!WebInspector.SourceMapNamesResolver.Identifier>>}
*/
function onContent(content)
{
if (!content)
return Promise.resolve(new Map());

var startLocation = scope.startLocation();
var endLocation = scope.endLocation();
var textRange = new WebInspector.TextRange(startLocation.lineNumber, startLocation.columnNumber, endLocation.lineNumber, endLocation.columnNumber);
return Promise.resolve(/** @type {!Array<!WebInspector.SourceMapNamesResolver.Identifier>}*/([]));

var text = new WebInspector.Text(content);
var scopeText = text.extract(textRange);
var scopeStart = text.toSourceRange(textRange).offset;
var scopeRange = new WebInspector.TextRange(startLocation.lineNumber, startLocation.columnNumber, endLocation.lineNumber, endLocation.columnNumber)
var scopeText = text.extract(scopeRange);
var scopeStart = text.toSourceRange(scopeRange).offset;
var prefix = "function fui";

return WebInspector.SourceMapNamesResolverWorker._instance().javaScriptIdentifiers(prefix + scopeText)
Expand All @@ -63,28 +59,124 @@ WebInspector.SourceMapNamesResolver._resolveScope = function(scope)
* @param {number} scopeStart
* @param {string} prefix
* @param {!Array<!{name: string, offset: number}>} identifiers
* @return {!Map<string, string>}
* @return {!Array<!WebInspector.SourceMapNamesResolver.Identifier>}
*/
function onIdentifiers(text, scopeStart, prefix, identifiers)
{
var namesMapping = new Map();
var lineEndings = text.lineEndings();

var result = [];
var cursor = new WebInspector.TextCursor(text.lineEndings());
var promises = [];
for (var i = 0; i < identifiers.length; ++i) {
var id = identifiers[i];
if (id.offset < prefix.length)
continue;
var start = scopeStart + id.offset - prefix.length;
cursor.resetTo(start);
result.push(new WebInspector.SourceMapNamesResolver.Identifier(id.name, cursor.lineNumber(), cursor.columnNumber()));
}
return result;
}
}

/**
* @param {!WebInspector.DebuggerModel.Scope} scope
* @return {!Promise.<!Map<string, string>>}
*/
WebInspector.SourceMapNamesResolver._resolveScope = function(scope)
{
var identifiersPromise = scope[WebInspector.SourceMapNamesResolver._cachedIdentifiersSymbol];
if (identifiersPromise)
return identifiersPromise;

var script = scope.callFrame().script;
var sourceMap = WebInspector.debuggerWorkspaceBinding.sourceMapForScript(script);
if (!sourceMap)
return Promise.resolve(new Map());

var lineNumber = lineEndings.lowerBound(start);
var columnNumber = start - (lineNumber === 0 ? 0 : (lineEndings[lineNumber - 1] + 1));
var entry = sourceMap.findEntry(lineNumber, columnNumber);
if (entry)
/** @type {!Map<string, !WebInspector.Text>} */
var textCache = new Map();
identifiersPromise = WebInspector.SourceMapNamesResolver._scopeIdentifiers(scope).then(onIdentifiers);
scope[WebInspector.SourceMapNamesResolver._cachedIdentifiersSymbol] = identifiersPromise;
return identifiersPromise;

/**
* @param {!Array<!WebInspector.SourceMapNamesResolver.Identifier>} identifiers
* @return {!Promise<!Map<string, string>>}
*/
function onIdentifiers(identifiers)
{
var namesMapping = new Map();
// Extract as much as possible from SourceMap.
for (var i = 0; i < identifiers.length; ++i) {
var id = identifiers[i];
var entry = sourceMap.findEntry(id.lineNumber, id.columnNumber);
if (entry && entry.name)
namesMapping.set(id.name, entry.name);
}

scope[WebInspector.SourceMapNamesResolver._cachedMapSymbol] = namesMapping;
delete scope[WebInspector.SourceMapNamesResolver._cachedPromiseSymbol];
WebInspector.SourceMapNamesResolver._scopeResolvedForTest();
return namesMapping;
// Resolve missing identifier names from sourcemap ranges.
var promises = [];
for (var i = 0; i < identifiers.length; ++i) {
var id = identifiers[i];
if (namesMapping.has(id.name))
continue;
var promise = resolveSourceName(id).then(onSourceNameResolved.bind(null, namesMapping, id));
promises.push(promise);
}
return Promise.all(promises)
.then(() => WebInspector.SourceMapNamesResolver._scopeResolvedForTest())
.then(() => namesMapping)
}

/**
* @param {!Map<string, string>} namesMapping
* @param {!WebInspector.SourceMapNamesResolver.Identifier} id
* @param {?string} sourceName
*/
function onSourceNameResolved(namesMapping, id, sourceName)
{
if (!sourceName)
return;
namesMapping.set(id.name, sourceName);
}

/**
* @param {!WebInspector.SourceMapNamesResolver.Identifier} id
* @return {!Promise<?string>}
*/
function resolveSourceName(id)
{
var startEntry = sourceMap.findEntry(id.lineNumber, id.columnNumber);
var endEntry = sourceMap.findEntry(id.lineNumber, id.columnNumber + id.name.length);
if (!startEntry || !endEntry || !startEntry.sourceURL || startEntry.sourceURL !== endEntry.sourceURL
|| !startEntry.sourceLineNumber || !startEntry.sourceColumnNumber
|| !endEntry.sourceLineNumber || !endEntry.sourceColumnNumber)
return Promise.resolve(/** @type {?string} */(null));
var sourceTextRange = new WebInspector.TextRange(startEntry.sourceLineNumber, startEntry.sourceColumnNumber, endEntry.sourceLineNumber, endEntry.sourceColumnNumber);
var uiSourceCode = WebInspector.networkMapping.uiSourceCodeForScriptURL(startEntry.sourceURL, script);
if (!uiSourceCode)
return Promise.resolve(/** @type {?string} */(null));

return uiSourceCode.requestContent()
.then(onSourceContent.bind(null, sourceTextRange));
}

/**
* @param {!WebInspector.TextRange} sourceTextRange
* @param {?string} content
* @return {?string}
*/
function onSourceContent(sourceTextRange, content)
{
if (!content)
return null;
var text = textCache.get(content);
if (!text) {
text = new WebInspector.Text(content);
textCache.set(content, text);
}
var originalIdentifier = text.extract(sourceTextRange).trim();
return /[a-zA-Z0-9_$]+/.test(originalIdentifier) ? originalIdentifier : null;
}
}

Expand Down Expand Up @@ -151,7 +243,7 @@ WebInspector.SourceMapNamesResolver.resolveExpression = function(callFrame, orig
if (reverseMapping.has(originalText))
return Promise.resolve(reverseMapping.get(originalText) || "");

return WebInspector.SourceMapNamesResolver._resolveExpression(callFrame, uiSourceCode, lineNumber, startColumnNumber, endColumnNumber)
return WebInspector.SourceMapNamesResolver._resolveExpression(callFrame, uiSourceCode, lineNumber, startColumnNumber, endColumnNumber);
}
}

Expand Down

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