getLog added to srv & clt-srv plumbing.

* Added `getLog` method to `Repository`.
  * Added `ILogOptions` to make the method friendlier to extension.
  * Options include `prevCount` and `format`, to effect our use case which is `git log -1 format=%B`.
* Added this to the client-server communication pipeline.

src/vs/workbench/parts/git/browser/gitServices.ts

@@ -38,6 +38,7 @@ import {IStorageService, StorageScope} from 'vs/platform/storage/common/storage'
 import Event from 'vs/base/common/event';
 import { domEvent } from 'vs/base/browser/event';
 import {IEditorGroupService} from 'vs/workbench/services/group/common/groupService';
+import { ILogOptions } from 'vs/workbench/parts/git/node/git.lib';
 
 function toReadablePath(path: string): string {
 	if (!platform.isWindows) {
@@ -695,6 +696,10 @@ export class GitService extends ee.EventEmitter
 		return this.raw.getCommitTemplate();
 	}
 
+	public getLog(options?: ILogOptions): winjs.Promise {
+		return this.raw.getLog(options);
+	}
+
 	public detectMimetypes(path: string, treeish: string = '~'): winjs.Promise {
 		return this.raw.detectMimetypes(path, treeish);
 	}

src/vs/workbench/parts/git/common/git.ts

@@ -10,6 +10,7 @@ import { IEventEmitter } from 'vs/base/common/eventEmitter';
 import { IDisposable } from 'vs/base/common/lifecycle';
 import { createDecorator } from 'vs/platform/instantiation/common/instantiation';
 import Event from 'vs/base/common/event';
+import { ILogOptions } from 'vs/workbench/parts/git/node/git.lib';
 
 // Model raw interfaces
 
@@ -287,6 +288,7 @@ export interface IRawGitService {
 	detectMimetypes(path: string, treeish?: string): TPromise<string[]>;
 	show(path: string, treeish?: string): TPromise<string>;
 	getCommitTemplate(): TPromise<string>;
+	getLog(options?: ILogOptions): TPromise<string>;
 }
 
 export const GIT_SERVICE_ID = 'gitService';
@@ -324,6 +326,7 @@ export interface IGitService extends IEventEmitter {
 	getRunningOperations(): IGitOperation[];
 	getAutoFetcher(): IAutoFetcher;
 	getCommitTemplate(): TPromise<string>;
+	getLog(options?: ILogOptions): TPromise<string>;
 }
 
 export interface IAskpassService {

src/vs/workbench/parts/git/common/gitIpc.ts

@@ -10,6 +10,7 @@ import { IChannel, eventToCall, eventFromCall } from 'vs/base/parts/ipc/common/i
 import Event from 'vs/base/common/event';
 import { IRawGitService, RawServiceState, IRawStatus, IPushOptions, IAskpassService, ICredentials,
 	ServiceState, IRawFileStatus, IBranch, RefType, IRef, IRemote } from './git';
+import { ILogOptions } from 'vs/workbench/parts/git/node/git.lib';
 
 type ISerializer<A,B> = { to(a: A): B; from(b: B): A; };
 
@@ -88,6 +89,7 @@ export interface IGitChannel extends IChannel {
 	call(command: 'show', args: [string, string]): TPromise<string>;
 	call(command: 'onOutput'): TPromise<void>;
 	call(command: 'getCommitTemplate'): TPromise<string>;
+	call(command: 'getLog', options?: ILogOptions): TPromise<string>;
 	call(command: string, args: any): TPromise<any>;
 }
 
@@ -119,6 +121,7 @@ export class GitChannel implements IGitChannel {
 			case 'show': return this.service.then(s => s.show(args[0], args[1]));
 			case 'onOutput': return this.service.then(s => eventToCall(s.onOutput));
 			case 'getCommitTemplate': return this.service.then(s => s.getCommitTemplate());
+			case 'getLog': return this.service.then(s => s.getLog(args));
 		}
 	}
 }
@@ -223,6 +226,10 @@ export class GitChannelClient implements IRawGitService {
 	getCommitTemplate(): TPromise<string> {
 		return this.channel.call('getCommitTemplate');
 	}
+
+	getLog(options?: ILogOptions): TPromise<string> {
+		return this.channel.call('getLog', options);
+	}
 }
 
 export interface IAskpassChannel extends IChannel {

src/vs/workbench/parts/git/common/noopGitService.ts

@@ -7,6 +7,7 @@
 import { IRawGitService, IRawStatus, ServiceState, RawServiceState } from 'vs/workbench/parts/git/common/git';
 import { TPromise } from 'vs/base/common/winjs.base';
 import Event, { Emitter } from 'vs/base/common/event';
+import { ILogOptions } from 'vs/workbench/parts/git/node/git.lib';
 
 export class NoOpGitService implements IRawGitService {
 
@@ -105,4 +106,8 @@ export class NoOpGitService implements IRawGitService {
 	getCommitTemplate(): TPromise<string> {
 		return TPromise.as(null);
 	}
+
+	getLog(options?: ILogOptions): TPromise<string> {
+		return TPromise.as(null);
+	}
 }

src/vs/workbench/parts/git/node/git.lib.ts

@@ -118,6 +118,18 @@ export class GitError {
 	}
 }
 
+export interface ILogOptions {
+	/**
+	 * @example `git log -1 --format=%B` to get the last commit log, message only
+	 */
+	prevCount?: number;
+
+	/**
+	 * @example format: "%B" translates to `git log --format=%B` to extract only the message
+	 */
+	format?: string;
+}
+
 export interface IGitOptions {
 	gitPath:string;
 	version: string;
@@ -719,6 +731,20 @@ export class Repository {
 		}, () => '');
 	}
 
+	/** Implemented for use case `git log` and `git log -N`. */
+	getLog(options?: ILogOptions): TPromise<string> {
+		const args = ['log'];
+
+		if (options) {
+			if (options.prevCount) { args.push(`-${options.prevCount}`); }
+			if (options.format) { args.push(`--format=${options.format}`); }
+		}
+
+		return this.run(args, { log: false }).then(result => {
+			return result.stdout.trim();
+		});
+	}
+
 	onOutput(listener: (output: string) => void): () => void {
 		return this.git.onOutput(listener);
 	}

src/vs/workbench/parts/git/node/rawGitService.ts

@@ -8,7 +8,7 @@ import { join } from 'path';
 import { TPromise, Promise } from 'vs/base/common/winjs.base';
 import { detectMimesFromFile, detectMimesFromStream } from 'vs/base/node/mime';
 import { realpath, exists} from 'vs/base/node/pfs';
-import { Repository, GitError } from 'vs/workbench/parts/git/node/git.lib';
+import { Repository, GitError, ILogOptions } from 'vs/workbench/parts/git/node/git.lib';
 import { IRawGitService, RawServiceState, IRawStatus, IRef, GitErrorCodes, IPushOptions } from 'vs/workbench/parts/git/common/git';
 import Event, { Emitter, fromPromise } from 'vs/base/common/event';
 
@@ -199,6 +199,10 @@ export class RawGitService implements IRawGitService {
 	getCommitTemplate(): TPromise<string> {
 		return this.repo.getCommitTemplate();
 	}
+
+	getLog(options?: ILogOptions): TPromise<string> {
+		return this.repo.getLog(options);
+	}
 }
 
 export class DelayedRawGitService implements IRawGitService {
@@ -225,4 +229,5 @@ export class DelayedRawGitService implements IRawGitService {
 	detectMimetypes(path: string, treeish?: string): TPromise<string[]> { return this.raw.then(r => r.detectMimetypes(path, treeish)); }
 	show(path: string, treeish?: string): TPromise<string> { return this.raw.then(r => r.show(path, treeish)); }
 	getCommitTemplate(): TPromise<string> { return this.raw.then(r => r.getCommitTemplate()); }
+	getLog(options?: ILogOptions): TPromise<string> { return this.raw.then(r => r.getLog(options)); }
 }