add function to get commit detail

src/git-command-manager.ts

@@ -5,6 +5,19 @@ import * as path from 'path'
 
 const tagsRefSpec = '+refs/tags/*:refs/tags/*'
 
+export type Commit = {
+  sha: string
+  tree: string
+  parents: string[]
+  subject: string
+  body: string
+  changes: {
+    mode: string
+    status: 'A' | 'M' | 'D'
+    path: string
+  }[]
+}
+
 export class GitCommandManager {
   private gitPath: string
   private workingDirectory: string
@@ -138,6 +151,41 @@ export class GitCommandManager {
     await this.exec(args)
   }
 
+  async getCommit(ref: string): Promise<Commit> {
+    const endOfBody = '###EOB###'
+    const output = await this.exec([
+      'show',
+      '--raw',
+      '--cc',
+      '--diff-filter=AMD',
+      `--format=%H%n%T%n%P%n%s%n%b%n${endOfBody}`,
+      ref
+    ])
+    const lines = output.stdout.split('\n')
+    const endOfBodyIndex = lines.lastIndexOf(endOfBody)
+    const detailLines = lines.slice(0, endOfBodyIndex)
+
+    return <Commit>{
+      sha: detailLines[0],
+      tree: detailLines[1],
+      parents: detailLines[2].split(' '),
+      subject: detailLines[3],
+      body: detailLines.slice(4, endOfBodyIndex).join('\n'),
+      changes: lines.slice(endOfBodyIndex + 2, -1).map(line => {
+        const change = line.match(/^:\d{6} (\d{6}) \w{7} \w{7} ([AMD])\s+(.*)$/)
+        if (change) {
+          return {
+            mode: change[1],
+            status: change[2],
+            path: change[3]
+          }
+        } else {
+          throw new Error(`Unexpected line format: ${line}`)
+        }
+      })
+    }
+  }
+
   async getConfigValue(configKey: string, configValue = '.'): Promise<string> {
     const output = await this.exec([
       'config',