From 60cb46c4b5027f7f6bfe776569a06f3f2c5a1b54 Mon Sep 17 00:00:00 2001
From: Andrew Head <head.andrewm@gmail.com>
Date: Wed, 27 Feb 2019 21:24:42 -0800
Subject: [PATCH] UI: Enabled the revision browser for Jupyter Lab once again

---
 src/overlay/revision-browser.ts | 100 ++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 src/overlay/revision-browser.ts

diff --git a/src/overlay/revision-browser.ts b/src/overlay/revision-browser.ts
new file mode 100644
index 0000000..76c03de
--- /dev/null
+++ b/src/overlay/revision-browser.ts
@@ -0,0 +1,100 @@
+import { nbformat } from "@jupyterlab/coreutils";
+import { RenderMimeRegistry, standardRendererFactories } from "@jupyterlab/rendermime";
+import { PanelLayout, Widget } from "@phosphor/widgets";
+import { GatherModel, GatherState } from "../model/model";
+import { log } from "../util/log";
+import { DisplayData } from "../widgets/displaydata";
+import { buildHistoryModel, HistoryViewer } from "../widgets/history";
+import { IOutputRenderer } from "../widgets/revision";
+
+/**
+ * Class for the revision browser widget.
+ */
+const REVISION_BROWSER_CLASS = "jp-Notebook-revisionbrowser";
+
+/**
+ * Class for output areas in the revision browser.
+ */
+const REVISION_OUTPUT_CLASS = "jp-Notebook-revisionbrowser-output";
+
+
+/**
+ * Renders output models for notebooks as new cells.
+ */
+class OutputRenderer implements IOutputRenderer {
+    /**
+     * Render HTML element for this output.
+     */
+    render(output: nbformat.IOutput): HTMLElement {
+        let widget = new DisplayData({
+            model: output,
+            rendermime: new RenderMimeRegistry({ initialFactories: standardRendererFactories })
+        });
+        widget.addClass(REVISION_OUTPUT_CLASS);
+        return widget.node;
+    }
+}
+
+/**
+ * Window that lets the user browse revisions of code.
+ */
+export class RevisionBrowser extends Widget {
+    /**
+     * Construct a new revision browser.
+     */
+    constructor(gatherModel: GatherModel) {
+        super();
+        this.id = "revision-browser";
+        this.title.label = "Revision browser";
+        this.title.icon = "jp-HistoryIcon";
+        this.title.closable = true;
+        this.addClass(REVISION_BROWSER_CLASS);
+
+        this._gatherModel = gatherModel;
+        this._outputRenderer = new OutputRenderer();
+        this.layout = new PanelLayout();
+
+        this.attachSliceWidgets(gatherModel);
+    }
+
+    attachSliceWidgets(model: GatherModel) {
+        let defSelections = model.selectedDefs;
+        let outputSelections = model.selectedOutputs;
+        let slices;
+        let cellPersistentId;
+        if (defSelections.length > 0) {
+            slices = model.getSelectedDefSlices(defSelections[0]);
+            cellPersistentId = defSelections[0].cell.persistentId;
+        } else if (outputSelections.length > 0) {
+            slices = model.getSelectedOutputSlices(outputSelections[0]);
+            cellPersistentId = outputSelections[0].cell.persistentId;
+        }
+        log("Bringing up the revision browser for selection", {
+            cellPersistendId: cellPersistentId, slices,
+            selectedDefs: model.selectedDefs,
+            selectedOutputs: model.selectedOutputs
+        });
+        if (slices && cellPersistentId) {
+            // Only show output if the selection was output.
+            let includeOutput = model.selectedOutputs.length >= 1;
+            let historyModel = buildHistoryModel(
+                model, cellPersistentId, slices, includeOutput);
+            let historyViewer = new HistoryViewer({
+                model: historyModel,
+                outputRenderer: this._outputRenderer
+            });
+            (this.layout as PanelLayout).addWidget(historyViewer);
+        }
+    }
+
+    /**
+     * Dismiss this widget.
+     */
+    dismiss() {
+        log("Dismissing revision browser");
+        this._gatherModel.requestStateChange(GatherState.SELECTING);
+    }
+
+    private _gatherModel: GatherModel;
+    private _outputRenderer: OutputRenderer;
+}
\ No newline at end of file