Reworks git abstraction and acccess

Adds commands module
Adds git commit message to blame hover decorator

src/commands.ts

@@ -0,0 +1,44 @@
+'use strict'
+import {commands, Disposable, Position, Range, Uri, window} from 'vscode';
+import {Commands, VsCodeCommands} from './constants';
+import GitProvider from './gitProvider';
+
+abstract class Command extends Disposable {
+    private _subscriptions: Disposable;
+
+    constructor(command: Commands) {
+        super(() => this.dispose());
+        this._subscriptions = commands.registerCommand(command, this.execute.bind(this));
+    }
+
+    dispose() {
+        this._subscriptions && this._subscriptions.dispose();
+        super.dispose();
+    }
+
+    abstract execute(...args): any;
+}
+
+export class BlameCommand extends Command {
+    constructor(private git: GitProvider) {
+        super(Commands.ShowBlameHistory);
+    }
+
+    execute(uri?: Uri, range?: Range, position?: Position) {
+        // If the command is executed manually -- treat it as a click on the root lens (i.e. show blame for the whole file)
+        if (!uri) {
+            const doc = window.activeTextEditor && window.activeTextEditor.document;
+            if (doc) {
+                uri = doc.uri;
+                range = doc.validateRange(new Range(0, 0, 1000000, 1000000));
+                position = doc.validateRange(new Range(0, 0, 0, 1000000)).start;
+            }
+
+            if (!uri) return;
+        }
+
+        return this.git.getBlameLocations(uri.path, range).then(locations => {
+            return commands.executeCommand(VsCodeCommands.ShowReferences, uri, position, locations);
+        });
+    }
+}