DevTools: edit SASS through SourceMaps.

Source/devtools/front_end/bindings/SASSSourceMapping.js

Index: Source/devtools/front_end/bindings/SASSSourceMapping.js
diff --git a/Source/devtools/front_end/bindings/SASSSourceMapping.js b/Source/devtools/front_end/bindings/SASSSourceMapping.js
index 422b8c3224ce25b1e2a2f6de2d8d2ef6fea054e3..8778a0417fd879307817424c11c205a12ec5b872 100644
--- a/Source/devtools/front_end/bindings/SASSSourceMapping.js
+++ b/Source/devtools/front_end/bindings/SASSSourceMapping.js
@@ -52,6 +52,8 @@ WebInspector.SASSSourceMapping = function(cssModel, workspace, networkMapping, n
     this._workspace.addEventListener(WebInspector.Workspace.Events.UISourceCodeContentCommitted, this._uiSourceCodeContentCommitted, this);
     this._workspace.addEventListener(WebInspector.Workspace.Events.ProjectRemoved, this._reset, this);
     this._networkMapping = networkMapping;
+
+    this._editor = new WebInspector.SASSSourceMapping.Editor(workspace, networkMapping, cssModel, this);
 }
 
 WebInspector.SASSSourceMapping.prototype = {
@@ -65,6 +67,7 @@ WebInspector.SASSSourceMapping.prototype = {
             --this._addingRevisionCounter;
             return;
         }
+        return;
         var header = this._cssModel.styleSheetHeaderForId(id);
         if (!header)
             return;
@@ -651,5 +654,425 @@ WebInspector.SASSSourceMapping.prototype = {
         /** @type {!Object.<string, !WebInspector.SourceMap>} */
         this._sourceMapByURL = {};
         this._sourceMapByStyleSheetURL = {};
+    },
+
+    _sourceMapForCSSURL: function(cssURL)
+    {
+        var sassURL = this._completeSourceMapURLForCSSURL[cssURL];
+        if (!sassURL)
+            return null;
+        return this._sourceMapByURL[sassURL] || null;
     }
 }
+
+WebInspector.SASSSourceMapping.Editor = function(workspace, networkMapping, cssModel, sassSourceMapping)
+{
+    this._workspace = workspace;
+    this._networkMapping = networkMapping;
+    this._cssModel = cssModel;
+    this._sassSourceMapping = sassSourceMapping;
+
+    this._workspace.addEventListener(WebInspector.Workspace.Events.UISourceCodeAdded, this._uiSourceCodeAddedToWorkspace, this);
+    this._workspace.addEventListener(WebInspector.Workspace.Events.UISourceCodeRemoved, this._uiSourceCodeRemoved, this);
+
+    this._contents = new Map();
+    this._changedURLs = new Set();
+    this._throttler = new WebInspector.Throttler(0);
+}
+
+WebInspector.SASSSourceMapping.Editor.prototype = {
+    _uiSourceCodeRemoved: function(event)
+    {
+        event.data.removeEventListener(WebInspector.UISourceCode.Events.WorkingCopyCommitted, this._sourceCodeCommitted, this);
+    },
+
+    _uiSourceCodeAddedToWorkspace: function(event)
+    {
+        var uiSourceCode = event.data;
+        var url = uiSourceCode.originURL();
+        if (!this._cssModel.styleSheetIdsForURL(url).length)
+            return;
+        uiSourceCode.addEventListener(WebInspector.UISourceCode.Events.WorkingCopyCommitted, this._sourceCodeCommitted, this);
+        uiSourceCode.requestContentPromise().then(setContent.bind(this));
+
+        function setContent(text)
+        {
+            this._contents.set(url, text);
+        }
+    },
+
+    _killMappingForURL: function(cssURL)
+    {
+        var ids = this._cssModel.styleSheetIdsForURL(cssURL);
+        for (var id of ids) {
+            var header = this._cssModel.styleSheetHeaderForId(id);
+            this._sassSourceMapping.removeHeader(header);
+        }
+    },
+
+    _sourceCodeCommitted: function(event)
+    {
+        if (this._muteSourceCodeCommitted)
+            return;
+
+        var sourceURL = this._networkMapping.networkURL(event.target);
+        this._changedURLs.add(sourceURL);
+        this._throttler.schedule(this._processChangedSourceCodes.bind(this));
+    },
+
+    _processChangedSourceCodes: function()
+    {
+        console.log("React!");
+        //FIXME: handle all changes.
+        var cssSourceURL = this._changedURLs.valuesArray()[0];
+        this._changedURLs.clear();
+
+        var uiSourceCode = this._networkMapping.uiSourceCodeForURL(cssSourceURL, this._cssModel.target());
+        var historyLength = uiSourceCode.history.length;
+        var oldCSSContent = this._contents.get(cssSourceURL);
+        var newCSSContent = uiSourceCode.history[historyLength - 1].content;
+
+        var sourceMap = this._sassSourceMapping._sourceMapForCSSURL(cssSourceURL);
+        if (!sourceMap)
+            return Promise.resolve();
+        var edits = WebInspector.SourceMapEditor.computeEdits(cssSourceURL, oldCSSContent, newCSSContent);
+        edits.sort(sequentialOrder);
+        // New sourcemap which maps to content.
+        var newSourceMap = sourceMap.clone();
+        for (var i = edits.length - 1; i >= 0; --i)
+            newSourceMap.compiledRangeEdited(edits[i].oldRange, edits[i].newRange());
+
+        var parser = new WebInspector.CSSParser();
+
+        var oldCSSStruct, newCSSStruct;
+
+        var parsePromise = parser.parsePromise(oldCSSContent)
+            .then(function(struct) { oldCSSStruct = struct; return parser.parsePromise(newCSSContent);})
+            .then(function(struct) { newCSSStruct = struct; parser.dispose(); })
+            .then(onCSSStructs);
+
+        var urlsToRequest = new Set();
+        for (var i = 0; i < edits.length; ++i) {
+            var edit = edits[i];
+            urlsToRequest.add(edit.sourceURL);
+            var mapping = sourceMap.findEntry(edit.oldRange.startLine, edit.oldRange.startColumn);
+            urlsToRequest.add(mapping.sourceURL);
+        }
+
+        var sources = new Map();
+        var sourcePromises = [];
+        for (var url of urlsToRequest) {
+            var uiSourceCode = this._networkMapping.uiSourceCodeForURL(url, this._cssModel.target());
+            var promise = uiSourceCode.requestContentPromise().then(setSource.bind(null, sources, url));
+            sourcePromises.push(promise);
+        }
+
+        return Promise.all([parsePromise, Promise.all(sourcePromises)]).spread(doEdits.bind(this))
+            .catch(killMapping.bind(this, cssSourceURL));
+
+        function setSource(sources, sourceURL, content)
+        {
+            if (typeof content !== "string")
+                throw new Error("Failed to fetch content of " + sourceURL);
+            sources.set(sourceURL, content);
+        }
+
+        function onCSSStructs()
+        {
+            return WebInspector.SASSSourceMapping.diffCSSStructs(oldCSSStruct, newCSSStruct);
+        }
+
+        function doEdits(structuralDiff)
+        {
+            function mapCSStoSASS(cssLine, cssColumn, sassEdit, useEnd)
+            {
+                var sassLineNumber = useEnd ? sassEdit.newRange().endLine : sassEdit.newRange().startLine;
+                var sassColumnNumber = useEnd ? sassEdit.newRange().endColumn : sassEdit.newRange().startColumn;
+                var mapping = new WebInspector.SourceMap.Entry(cssLine, cssColumn, sassEdit.sourceURL, sassLineNumber, sassColumnNumber);
+                ensureMappings.set(sassEdit, mapping);
+            }
+
+            if (this._changedURLs.size > 0)
+                return;
+            var structureMapping = new WebInspector.SASSStructureMapping(newCSSStruct, sources);
+
+            var edits = [];
+            var ensureMappings = new Map();
+            for (var i = 0; i < structuralDiff.length; ++i) {
+                //FIXME: handle other types of edits.
+                var diff = structuralDiff[i];
+                if (diff.type === "ValueChanged") {
+                    var cssProperty = diff.property;
+                    var sassValue = structureMapping.cssPropertyValueToSASS(WebInspector.TextRange.fromObject(cssProperty.valueRange), newSourceMap);
+                    var sassContent = sources.get(sassValue.url);
+                    var sassEdit = new WebInspector.SourceMapEdit(sassValue.url, sassValue.range, sassValue.range.extract(sassContent), " " + cssProperty.value.trim());
+                    edits.push(sassEdit);
+                    mapCSStoSASS(cssProperty.valueRange.startLine, cssProperty.valueRange.startColumn, sassEdit, false);
+
+                    var backEdits = structureMapping.sassPropertyValueToCSS(sassValue.url, sassValue.range, newSourceMap);
+                    if (backEdits.length === 1)
+                        continue;
+                    for (var j = 0; j < backEdits.length; ++j) {
+                        var backEditProperty = backEdits[j];
+                        if (backEditProperty === cssProperty)
+                            continue;
+                        var oldRange = WebInspector.TextRange.fromObject(backEditProperty.valueRange);
+                        var oldText = oldRange.extract(newCSSContent);
+                        var cssEdit = new WebInspector.SourceMapEdit(cssSourceURL, oldRange, oldText, sassEdit.newText);
+                        edits.push(cssEdit);
+                        var mapping = new WebInspector.SourceMap.Entry(oldRange.startLine, oldRange.startColumn, sassValue.url, sassValue.range.startLine, sassValue.range.startColumn);
+                        ensureMappings.set(cssEdit, mapping);
+                    }
+                } else if (diff.type === "PropertyAdded") {
+                    var cssProperty = diff.property;
+                    if (diff.after) {
+                        var afterCSSProperty = diff.after;
+                        var afterSASSProperty = structureMapping.cssPropertyToSASS(afterCSSProperty.range, newSourceMap);
+                        var url = afterSASSProperty.url;
+                        var sassContent = sources.get(url);
+                        var oldRange = WebInspector.TextRange.createFromLocation(afterSASSProperty.range.endLine, afterSASSProperty.range.endColumn);
+                        var indent = (new WebInspector.TextRange(afterSASSProperty.range.startLine, 0, afterSASSProperty.range.startLine, afterSASSProperty.range.startColumn)).extract(sassContent);
+                        if (!/^\s+$/.test(indent)) indent = "";
+
+                        // Split property addition into chunks to preserve mappings.
+                        var newText = String.sprintf("\n%s", indent);
+                        var edit1 = new WebInspector.SourceMapEdit(url, oldRange, "", newText);
+                        mapCSStoSASS(cssProperty.range.startLine, cssProperty.range.startColumn, edit1, true);
+
+                        var newText = String.sprintf("%s:", cssProperty.name.trim());
+                        var edit2 = new WebInspector.SourceMapEdit(url, oldRange, "", newText);
+                        mapCSStoSASS(cssProperty.valueRange.startLine, cssProperty.valueRange.startColumn, edit2, true);
+
+                        var newText = String.sprintf(" %s;", cssProperty.value.trim());
+                        var edit3 = new WebInspector.SourceMapEdit(url, oldRange, "", newText);
+                        mapCSStoSASS(cssProperty.range.endLine, cssProperty.range.endColumn, edit3, true);
+
+                        edits.push(edit3, edit2, edit1);
+                    } else if (diff.before) {
+                        var beforeCSSProperty = diff.before;
+                        var beforeSASSProperty = structureMapping.cssPropertyToSASS(beforeCSSProperty.range, newSourceMap);
+                        var url = beforeSASSProperty.url;
+                        var sassContent = sources.get(url);
+                        var oldRange = WebInspector.TextRange.createFromLocation(beforeSASSProperty.range.startLine, beforeSASSProperty.range.startColumn);
+                        var indent = (new WebInspector.TextRange(beforeSASSProperty.range.startLine, 0, beforeSASSProperty.range.startLine, beforeSASSProperty.range.startColumn)).extract(sassContent);
+                        if (!/^\s+$/.test(indent)) indent = "";
+
+                        // Split property addition into chunks to preserve mappings.
+                        var newText = String.sprintf("%s:", cssProperty.name.trim());
+                        var edit1 = new WebInspector.SourceMapEdit(url, oldRange, "", newText);
+                        mapCSStoSASS(cssProperty.range.startLine, cssProperty.range.startColumn, edit1);
+
+                        var newText = String.sprintf(" %s;", cssProperty.value.trim());
+                        var edit2 = new WebInspector.SourceMapEdit(url, oldRange, "", newText);
+                        mapCSStoSASS(cssProperty.valueRange.startLine, cssProperty.valueRange.startColumn, edit2);
+
+                        var newText = String.sprintf("\n%s", indent);
+                        var edit3 = new WebInspector.SourceMapEdit(url, oldRange, "", newText);
+                        mapCSStoSASS(cssProperty.range.endLine, cssProperty.range.endColumn, edit3);
+
+                        edits.push(edit3, edit2, edit1);
+                    }
+                    //FIXME: do back edits.
+                } else if (diff.type === "PropertyRemoved") {
+                    var cssProperty = diff.property;
+                    var sassProperty = structureMapping.cssPropertyToSASS(cssProperty.range, sourceMap);
+                    var sassContent = sources.get(sassProperty.url);
+                    var lineRemoveRange = new WebInspector.TextRange(sassProperty.range.startLine, 0, sassProperty.range.endLine + 1, 0);
+                    var oldRange = (lineRemoveRange.extract(sassContent).trim() === sassProperty.range.extract(sassContent).trim()) ? lineRemoveRange : sassProperty.range;
+                    var sassEdit = new WebInspector.SourceMapEdit(sassProperty.url, oldRange, oldRange.extract(sassContent), "");
+                    edits.push(sassEdit);
+                    //FIXME: do back edits.
+                }
+            }
+
+            // Categorize edits per url.
+            var editsPerURL = new Map();
+            for (var edit of edits) {
+                if (!editsPerURL.has(edit.sourceURL))
+                    editsPerURL.set(edit.sourceURL, []);
+                var list = editsPerURL.get(edit.sourceURL);
+                list.push(edit);
+            }
+
+            // Apply to CSS.
+            var cssEdits = editsPerURL.get(cssSourceURL);
+            if (cssEdits) {
+                cssEdits.stableSort(sequentialOrder);
+                // Apply edits in a reversed order so that they do not conflict with each other.
+                for (var i = cssEdits.length - 1; i >= 0; --i) {
+                    var cssEdit = cssEdits[i];
+                    newCSSContent = cssEdit.applyToText(newCSSContent);
+                    newSourceMap.compiledRangeEdited(cssEdit.oldRange, cssEdit.newRange());
+                    var ensureMapping = ensureMappings.get(cssEdit);
+                    // Add missing mappings to source map.
+                    if (ensureMapping)
+                        newSourceMap.ensureHasMapping(ensureMapping);
+                }
+                var uiSourceCode = this._networkMapping.uiSourceCodeForURL(cssSourceURL, this._cssModel.target());
+                this._muteSourceCodeCommitted = true;
+                uiSourceCode.addRevision(newCSSContent);
+                this._muteSourceCodeCommitted = false;
+            }
+            this._contents.set(cssSourceURL, newCSSContent);
+
+            // Apply to SASS.
+            for (var sassURL of editsPerURL.keys()) {
+                if (sassURL === cssSourceURL)
+                    continue;
+                var sassContent = sources.get(sassURL);
+                var sassEdits = editsPerURL.get(sassURL);
+                sassEdits.stableSort(sequentialOrder);
+                // Apply edits in a reversed order so that they do not conflict with each other.
+                for (var i = sassEdits.length - 1; i >= 0; --i) {
+                    var sassEdit = sassEdits[i];
+                    sassContent = sassEdit.applyToText(sassContent);
+                    newSourceMap.sourceRangeEdited(sassEdit.sourceURL, sassEdit.oldRange, sassEdit.newRange());
+                    var ensureMapping = ensureMappings.get(sassEdit);
+                    // Add missing mappings to source map.
+                    if (ensureMapping)
+                        newSourceMap.ensureHasMapping(ensureMapping);
+                }
+                var uiSourceCode = this._networkMapping.uiSourceCodeForURL(sassURL, this._cssModel.target());
+                uiSourceCode.addRevision(sassContent);
+            }
+
+            // Hot-Swap source maps.
+            sourceMap._mappings = newSourceMap._mappings;
+            sourceMap._reverseMappingsBySourceURL = newSourceMap._reverseMappingsBySourceURL;
+        }
+
+        function sequentialOrder(range1, range2)
+        {
+            return range1.oldRange.follows(range2.oldRange) ? 1 : -1;
+        }
+
+        function killMapping(sourceURL, e)
+        {
+            console.error(e);
+            this._killMappingForURL(sourceURL);
+        }
+    }
+}
+
+WebInspector.SASSSourceMapping.diffCSSStructs = function(oldCSSStruct, newCSSStruct)
+{
+    oldCSSStruct = oldCSSStruct.filter(styleRulesFilter);
+    newCSSStruct = newCSSStruct.filter(styleRulesFilter);
+    if (oldCSSStruct.length !== newCSSStruct.length)
+        throw new Error("not implemented for rule diff.");
+    var structuralDiff = [];
+    for (var i = 0; i < oldCSSStruct.length; ++i) {
+        var oldRule = oldCSSStruct[i];
+        var newRule = newCSSStruct[i];
+        var removedSet = new Set();
+        var addedSet = new Set();
+        if (oldRule.properties.length !== newRule.properties.length)
+            WebInspector.SASSSourceMapping.cssPropertiesDiff(oldRule.properties, newRule.properties, removedSet, addedSet);
+        for (var property of removedSet.values()) {
+            structuralDiff.push({
+                type: "PropertyRemoved",
+                property: property
+            });
+        }
+        var firstValidProperty = null;
+        for (var j = 0; j < newRule.properties.length; ++j) {
+            var property = newRule.properties[j];
+            if (!addedSet.has(property)) {
+                firstValidProperty = property;
+                break;
+            }
+        }
+        var lastValidProperty = null;
+        for (var j = 0; j < newRule.properties.length; ++j) {
+            var property = newRule.properties[j];
+            if (!addedSet.has(property)) {
+                lastValidProperty = property;
+                continue;
+            }
+            var diff = {
+                type: "PropertyAdded",
+                property: property,
+            };
+            if (lastValidProperty)
+                diff.after = lastValidProperty;
+            else if (firstValidProperty)
+                diff.before = firstValidProperty;
+            structuralDiff.push(diff);
+        }
+
+        var p1 = 0;
+        var p2 = 0;
+        while (p1 < oldRule.properties.length && p2 < newRule.properties.length) {
+            if (removedSet.has(oldRule.properties[p1])) {
+                ++p1;
+                continue;
+            }
+            if (addedSet.has(newRule.properties[p2])) {
+                ++p2;
+                continue;
+            }
+            var oldProperty = oldRule.properties[p1++];
+            var newProperty = newRule.properties[p2++];
+            if (oldProperty.name !== newProperty.name) {
+                structuralDiff.push({
+                    type: "NameChanged",
+                    property: newProperty
+                });
+            } else if (oldProperty.value !== newProperty.value) {
+                structuralDiff.push({
+                    type: "ValueChanged",
+                    property: newProperty
+                });
+            }
+        }
+    }
+    return structuralDiff;
+
+    function styleRulesFilter(rule)
+    {
+        return !!rule.properties;
+    }
+}
+
+WebInspector.SASSSourceMapping.cssPropertiesDiff = function(properties1, properties2, removedSet, addedSet)
+{
+    var charCode = 33;
+    var encodedProperties = new Map();
+    var text1 = doEncode(properties1);
+    var text2 = doEncode(properties2);
+    var differ = new diff_match_patch();
+    var diff = differ.diff_main(text1, text2);
+
+    var p1 = 0, p2 = 0;
+    for (var i = 0; i < diff.length; ++i) {
+        var token = diff[i];
+        if (token[0] === 0) {
+            p1 += token[1].length;
+            p2 += token[1].length;
+        } else if (token[0] === -1) {
+            for (var j = 0; j < token[1].length; ++j) {
+                var property = properties1[p1++];
+                removedSet.add(property);
+            }
+        } else {
+            for (var j = 0; j < token[1].length; ++j) {
+                var property = properties2[p2++];
+                addedSet.add(property);
+            }
+        }
+    }
+
+    function doEncode(properties)
+    {
+        var text = "";
+        for (var i = 0; i < properties.length; ++i) {
+            var encoded = encodedProperties.get(properties[i].name);
+            if (!encoded) {
+                encoded = String.fromCharCode(charCode++);
+                encodedProperties.set(properties[i].name, encoded);
+            }
+            text += encoded;
+        }
+        return text;
+    }
+}