8 files changed, 344 insertions, 77 deletions

diff --git a/app/assets/javascripts/repo/components/repo_editor.vue b/app/assets/javascripts/repo/components/repo_editor.vue
index 3c06e75a472..e0ce8a97665 100644
--- a/app/assets/javascripts/repo/components/repo_editor.vue
+++ b/app/assets/javascripts/repo/components/repo_editor.vue
@@ -3,21 +3,17 @@
 import { mapGetters, mapActions } from 'vuex';
 import flash from '../../flash';
 import monacoLoader from '../monaco_loader';
+import editor from '../lib/editor';
 
 export default {
   destroyed() {
-    if (this.monacoInstance) {
-      this.monacoInstance.destroy();
-    }
+    editor.dispose();
   },
   mounted() {
     if (this.monaco) {
       this.initMonaco();
     } else {
-      monacoLoader(['vs/editor/editor.main', 'vs/editor/common/diff/diffComputer'], (_, { DiffComputer }) => {
-        this.monaco = monaco;
-        this.DiffComputer = DiffComputer;
-
+      monacoLoader(['vs/editor/editor.main'], () => {
         this.initMonaco();
       });
     }
@@ -30,84 +26,25 @@ export default {
     initMonaco() {
       if (this.shouldHideEditor) return;
 
-      if (this.monacoInstance) {
-        this.monacoInstance.setModel(null);
-      }
+      editor.clearEditor();
 
       this.getRawFileData(this.activeFile)
         .then(() => {
-          if (!this.monacoInstance) {
-            this.monacoInstance = this.monaco.editor.create(this.$el, {
-              model: null,
-              readOnly: false,
-              contextmenu: true,
-              scrollBeyondLastLine: false,
-            });
-
-            this.languages = this.monaco.languages.getLanguages();
-          }
-
-          this.setupEditor();
+          editor.createInstance(this.$el);
         })
+        .then(() => this.setupEditor())
         .catch(() => flash('Error setting up monaco. Please try again.'));
     },
     setupEditor() {
       if (!this.activeFile) return;
-      const content = this.activeFile.content !== '' ? this.activeFile.content : this.activeFile.raw;
-
-      const foundLang = this.languages.find(lang =>
-        lang.extensions && lang.extensions.indexOf(this.activeFileExtension) === 0,
-      );
-      const newModel = this.monaco.editor.createModel(
-        content, foundLang ? foundLang.id : 'plaintext',
-      );
-      const originalLines = this.monaco.editor.createModel(
-        this.activeFile.raw, foundLang ? foundLang.id : 'plaintext',
-      ).getLinesContent();
-
-      this.monacoInstance.setModel(newModel);
-      this.decorations = [];
-
-      const modifiedType = (change) => {
-        if (change.originalEndLineNumber === 0) {
-          return 'added';
-        } else if (change.modifiedEndLineNumber === 0) {
-          return 'removed';
-        }
-
-        return 'modified';
-      };
-
-      this.monacoModelChangeContents = newModel.onDidChangeContent(() => {
-        const diffComputer = new this.DiffComputer(
-          originalLines,
-          newModel.getLinesContent(),
-          {
-            shouldPostProcessCharChanges: true,
-            shouldIgnoreTrimWhitespace: true,
-            shouldMakePrettyDiff: true,
-          },
-        );
 
-        this.decorations = this.monacoInstance.deltaDecorations(this.decorations,
-          diffComputer.computeDiff().map(change => ({
-            range: new monaco.Range(
-              change.modifiedStartLineNumber,
-              1,
-              !change.modifiedEndLineNumber ?
-                change.modifiedStartLineNumber : change.modifiedEndLineNumber,
-              1,
-            ),
-            options: {
-              isWholeLine: true,
-              linesDecorationsClassName: `dirty-diff dirty-diff-${modifiedType(change)}`,
-            },
-          })),
-        );
+      const model = editor.createModel(this.activeFile);
 
+      editor.attachModel(model);
+      model.onChange((m) => {
         this.changeFileContent({
           file: this.activeFile,
-          content: this.monacoInstance.getValue(),
+          content: m.getValue(),
         });
       });
     },
diff --git a/app/assets/javascripts/repo/lib/common/model.js b/app/assets/javascripts/repo/lib/common/model.js
new file mode 100644
index 00000000000..77d36b4f52c
--- /dev/null
+++ b/app/assets/javascripts/repo/lib/common/model.js
@@ -0,0 +1,46 @@
+/* global monaco */
+
+export default class Model {
+  constructor(file) {
+    this.file = file;
+    this.content = file.content !== '' ? file.content : file.raw;
+    this.originalModel = monaco.editor.createModel(
+      this.content,
+      undefined,
+      new monaco.Uri(null, null, `original/${this.file.path}`),
+    );
+    this.model = monaco.editor.createModel(
+      this.content,
+      undefined,
+      new monaco.Uri(null, null, this.file.path),
+    );
+    this.disposers = new Map();
+  }
+
+  get url() {
+    return this.model.uri.toString();
+  }
+
+  getModel() {
+    return this.model;
+  }
+
+  getOriginalModel() {
+    return this.originalModel;
+  }
+
+  onChange(cb) {
+    this.disposers.set(
+      this.file.path,
+      this.model.onDidChangeContent(e => cb(this.model, e)),
+    );
+  }
+
+  dispose() {
+    this.model.dispose();
+    this.originalModel.dispose();
+
+    this.disposers.forEach(disposer => disposer.dispose());
+    this.disposers.clear();
+  }
+}
diff --git a/app/assets/javascripts/repo/lib/decorations/controller.js b/app/assets/javascripts/repo/lib/decorations/controller.js
new file mode 100644
index 00000000000..0ab74f1ebdf
--- /dev/null
+++ b/app/assets/javascripts/repo/lib/decorations/controller.js
@@ -0,0 +1,46 @@
+import editor from '../editor';
+
+class DecorationsController {
+  constructor() {
+    this.decorations = new Map();
+    this.editorDecorations = new Map();
+  }
+
+  getAllDecorationsForModel(model) {
+    if (!this.decorations.has(model.url)) return [];
+
+    const modelDecorations = this.decorations.get(model.url);
+    const decorations = [];
+
+    modelDecorations.forEach(val => decorations.push(...val));
+
+    return decorations;
+  }
+
+  addDecorations(model, decorationsKey, decorations) {
+    const decorationMap = this.decorations.get(model.url) || new Map();
+
+    decorationMap.set(decorationsKey, decorations);
+
+    this.decorations.set(model.url, decorationMap);
+
+    this.decorate(model);
+  }
+
+  decorate(model) {
+    const decorations = this.getAllDecorationsForModel(model);
+    const oldDecorations = this.editorDecorations.get(model.url) || [];
+
+    this.editorDecorations.set(
+      model.url,
+      editor.instance.deltaDecorations(oldDecorations, decorations),
+    );
+  }
+
+  dispose() {
+    this.decorations.clear();
+    this.editorDecorations.clear();
+  }
+}
+
+export default new DecorationsController();
diff --git a/app/assets/javascripts/repo/lib/diff/controller.js b/app/assets/javascripts/repo/lib/diff/controller.js
new file mode 100644
index 00000000000..77d07b730cf
--- /dev/null
+++ b/app/assets/javascripts/repo/lib/diff/controller.js
@@ -0,0 +1,73 @@
+/* global monaco */
+import DirtyDiffWorker from './worker';
+import decorationsController from '../decorations/controller';
+
+export const getDiffChangeType = (change) => {
+  if (change.originalEndLineNumber === 0) {
+    return 'added';
+  } else if (change.modifiedEndLineNumber === 0) {
+    return 'removed';
+  }
+
+  return 'modified';
+};
+
+export const getDecorator = change => ({
+  range: new monaco.Range(
+    change.modifiedStartLineNumber,
+    1,
+    !change.modifiedEndLineNumber ?
+      change.modifiedStartLineNumber : change.modifiedEndLineNumber,
+    1,
+  ),
+  options: {
+    isWholeLine: true,
+    linesDecorationsClassName: `dirty-diff dirty-diff-${getDiffChangeType(change)}`,
+  },
+});
+
+export const decorate = (model, changes) => {
+  const decorations = changes.map(change => getDecorator(change));
+  decorationsController.addDecorations(model, 'dirtyDiff', decorations);
+};
+
+export default class DirtyDiffController {
+  constructor() {
+    this.editorSimpleWorker = null;
+    this.models = new Map();
+    this.worker = new DirtyDiffWorker();
+  }
+
+  attachModel(model) {
+    if (this.models.has(model.getModel().uri.toString())) return;
+
+    [model.getModel(), model.getOriginalModel()].forEach((iModel) => {
+      this.worker.attachModel({
+        url: iModel.uri.toString(),
+        versionId: iModel.getVersionId(),
+        lines: iModel.getLinesContent(),
+        EOL: '\n',
+      });
+    });
+
+    model.onChange((_, e) => this.computeDiff(model, e));
+
+    this.models.set(model.getModel().uri.toString(), model);
+  }
+
+  computeDiff(model, e) {
+    this.worker.modelChanged(model, e);
+    this.worker.compute(model, changes => decorate(model, changes));
+  }
+
+  // eslint-disable-next-line class-methods-use-this
+  reDecorate(model) {
+    decorationsController.decorate(model);
+  }
+
+  dispose() {
+    this.models.clear();
+    this.worker.dispose();
+    decorationsController.dispose();
+  }
+}
diff --git a/app/assets/javascripts/repo/lib/diff/worker.js b/app/assets/javascripts/repo/lib/diff/worker.js
new file mode 100644
index 00000000000..93d94f8d138
--- /dev/null
+++ b/app/assets/javascripts/repo/lib/diff/worker.js
@@ -0,0 +1,78 @@
+/* global monaco */
+export default class DirtyDiffWorker {
+  constructor() {
+    this.editorSimpleWorker = null;
+    this.models = new Map();
+    this.actions = new Set();
+
+    // eslint-disable-next-line promise/catch-or-return
+    monaco.editor.createWebWorker({
+      moduleId: 'vs/editor/common/services/editorSimpleWorker',
+    }).getProxy().then((editorSimpleWorker) => {
+      this.editorSimpleWorker = editorSimpleWorker;
+      this.ready();
+    });
+  }
+
+  // loop through all the previous cached actions
+  // this way we don't block the user from editing the file
+  ready() {
+    this.actions.forEach((action) => {
+      const methodName = Object.keys(action)[0];
+      this[methodName](...action[methodName]);
+    });
+
+    this.actions.clear();
+  }
+
+  attachModel(model) {
+    if (this.editorSimpleWorker && !this.models.has(model.url)) {
+      this.editorSimpleWorker.acceptNewModel(model);
+
+      this.models.set(model.url, model);
+    } else if (!this.editorSimpleWorker) {
+      this.actions.add({
+        attachModel: [model],
+      });
+    }
+  }
+
+  modelChanged(model, e) {
+    if (this.editorSimpleWorker) {
+      this.editorSimpleWorker.acceptModelChanged(
+        model.getModel().uri.toString(),
+        e,
+      );
+    } else {
+      this.actions.add({
+        modelChanged: [model, e],
+      });
+    }
+  }
+
+  compute(model, cb) {
+    if (this.editorSimpleWorker) {
+      // eslint-disable-next-line promise/catch-or-return
+      this.editorSimpleWorker.computeDiff(
+        model.getOriginalModel().uri.toString(),
+        model.getModel().uri.toString(),
+      ).then(cb);
+    } else {
+      this.actions.add({
+        compute: [model, cb],
+      });
+    }
+  }
+
+  dispose() {
+    this.models.forEach(model =>
+      this.editorSimpleWorker.acceptRemovedModel(model.url),
+    );
+    this.models.clear();
+
+    this.actions.clear();
+
+    this.editorSimpleWorker.dispose();
+    this.editorSimpleWorker = null;
+  }
+}
diff --git a/app/assets/javascripts/repo/lib/editor.js b/app/assets/javascripts/repo/lib/editor.js
new file mode 100644
index 00000000000..de1c6d61b10
--- /dev/null
+++ b/app/assets/javascripts/repo/lib/editor.js
@@ -0,0 +1,69 @@
+/* global monaco */
+import DirtyDiffController from './diff/controller';
+import Model from './common/model';
+
+class Editor {
+  constructor() {
+    this.models = new Map();
+    this.diffComputers = new Map();
+    this.currentModel = null;
+    this.instance = null;
+    this.dirtyDiffController = null;
+  }
+
+  createInstance(domElement) {
+    if (!this.instance) {
+      this.instance = monaco.editor.create(domElement, {
+        model: null,
+        readOnly: false,
+        contextmenu: true,
+        scrollBeyondLastLine: false,
+      });
+
+      this.dirtyDiffController = new DirtyDiffController();
+    }
+  }
+
+  createModel(file) {
+    if (this.models.has(file.path)) {
+      return this.models.get(file.path);
+    }
+
+    const model = new Model(file);
+    this.models.set(file.path, model);
+
+    return model;
+  }
+
+  attachModel(model) {
+    this.instance.setModel(model.getModel());
+    this.dirtyDiffController.attachModel(model);
+
+    this.currentModel = model;
+
+    this.dirtyDiffController.reDecorate(model);
+  }
+
+  clearEditor() {
+    if (this.instance) {
+      this.instance.setModel(null);
+    }
+  }
+
+  dispose() {
+    // dispose main monaco instance
+    if (this.instance) {
+      this.instance.dispose();
+      this.instance = null;
+    }
+
+    // dispose of all the models
+    this.models.forEach(model => model.dispose());
+    this.models.clear();
+
+    this.dirtyDiffController.dispose();
+    this.dirtyDiffController = null;
+  }
+}
+
+export default new Editor();
diff --git a/app/assets/javascripts/repo/services/index.js b/app/assets/javascripts/repo/services/index.js
index 2fb45dcb03c..994d325e991 100644
--- a/app/assets/javascripts/repo/services/index.js
+++ b/app/assets/javascripts/repo/services/index.js
@@ -16,6 +16,10 @@ export default {
       return Promise.resolve(file.content);
     }
 
+    if (file.raw) {
+      return Promise.resolve(file.raw);
+    }
+
     return Vue.http.get(file.rawPath, { params: { format: 'json' } })
       .then(res => res.text());
   },
diff --git a/app/assets/stylesheets/pages/repo.scss b/app/assets/stylesheets/pages/repo.scss
index 35b5862374b..a2a2bc408db 100644
--- a/app/assets/stylesheets/pages/repo.scss
+++ b/app/assets/stylesheets/pages/repo.scss
@@ -70,6 +70,7 @@
 
       .line-numbers {
         cursor: pointer;
+        min-width: initial;
 
         &:hover {
           text-decoration: underline;
@@ -309,16 +310,29 @@
 	left: 0 !important;
 
   &-modified {
-    background-color: rgb(19, 117, 150);
+    background-color: $blue-500;
   }
 
   &-added {
-    background-color: rgb(89, 119, 11);
+    background-color: $green-600;
   }
 
   &-removed {
-    height: 4px!important;
+    height: 0!important;
+    width: 0!important;
     bottom: -2px;
-    background-color: red;
+    border-style: solid;
+    border-width: 5px;
+    border-color: transparent transparent transparent $red-500;
+
+    &::before {
+      content: '';
+      position: absolute;
+      left: 0;
+      top: 0;
+      width: 100px;
+      height: 1px;
+      background-color: rgba($red-500, .5);
+    }
   }
 }