initial commit

Signed-off-by: dzdidi <deniszalessky@gmail.com>

src/git.js

@@ -0,0 +1,181 @@
+const { getCodePath } = require('./appHome')
+const { spawn } = require('child_process')
+
+async function lsPromise (url) {
+  const ls = spawn('git', ['ls-remote', url])
+  const res = {}
+
+  ls.stdout.on('data', lines => lines.toString().split('\n').forEach((line) => {
+    if (!line) return
+
+    const [sha, branch] = line.split('\t')
+    res[branch] = sha
+  }))
+
+  return new Promise((resolve, reject) => {
+    ls.on('close', (code) => {
+      if (!code) return resolve(res)
+
+      reject(new Error(`git ls-remote exited with code ${code}`))
+    })
+  })
+}
+
+async function createBareRepo (name) {
+  const init = spawn('git', ['init', '--bare'], { env: { GIT_DIR: getCodePath(name) } })
+  init.stderr.pipe(process.stderr)
+  return new Promise((resolve, reject) => {
+    init.on('close', (code) => {
+      if (code) return reject(new Error(`git init exited with code ${code}`))
+
+      resolve()
+    })
+  })
+}
+
+async function addRemote (name) {
+  const init = spawn('git', ['remote', 'add', 'pear', getCodePath(name)])
+  init.stderr.pipe(process.stderr)
+  return new Promise((resolve, reject) => {
+    init.on('close', (code) => {
+      if (code) {
+        return reject(new Error(`git remote add exited with code ${code}`))
+      }
+
+      return resolve()
+    })
+  })
+}
+
+function pad4 (num) {
+  num = num.toString(16)
+  while (num.length < 4) {
+    num = '0' + num
+  }
+  return num
+}
+
+function uploadPack (dir, want, have) {
+  // reference:
+  // https://github.com/git/git/blob/b594c975c7e865be23477989d7f36157ad437dc7/Documentation/technical/pack-protocol.txt#L346-L393
+  const upload = spawn('git-upload-pack', [dir])
+  writeln('want ' + want)
+  writeln()
+  if (have) {
+    writeln('have ' + have)
+    writeln()
+  }
+  writeln('done')
+
+  // We want to read git's output one line at a time, and not read any more
+  // than we have to. That way, when we finish discussing wants and haves, we
+  // can pipe the rest of the output to a stream.
+  //
+  // We use `mode` to keep track of state and formulate responses. It returns
+  // `false` when we should stop reading.
+  let mode = list
+  upload.stdout.on('readable', function () {
+    while (true) {
+      const line = getline()
+      if (line === null) {
+        return // to wait for more output
+      }
+      if (!mode(line)) {
+        upload.stdout.removeAllListeners('readable')
+        upload.emit('ready')
+        return
+      }
+    }
+  })
+
+  let getLineLen = null
+  // Extracts exactly one line from the stream. Uses `getLineLen` in case the
+  // whole line could not be read.
+  function getline () {
+    // Format: '####line' where '####' represents the length of 'line' in hex.
+    if (!getLineLen) {
+      getLineLen = upload.stdout.read(4)
+      if (getLineLen === null) {
+        return null
+      }
+      getLineLen = parseInt(getLineLen, 16)
+    }
+
+    if (getLineLen === 0) {
+      return ''
+    }
+
+    // Subtract by the four we just read, and the terminating newline.
+    const line = upload.stdout.read(getLineLen - 4 - 1)
+    if (!line) {
+      return null
+    }
+    getLineLen = null
+    upload.stdout.read(1) // And discard the newline.
+    return line.toString()
+  }
+
+  // First, the server lists the refs it has, but we already know from
+  // `git ls-remote`, so wait for it to signal the end.
+  function list (line) {
+    if (line === '') {
+      mode = have ? ackObjectsContinue : waitForNak
+    }
+    return true
+  }
+
+  // If we only gave wants, git should respond with 'NAK', then the pack file.
+  function waitForNak (line) {
+    return line !== 'NAK'
+  }
+
+  // With haves, we wait for 'ACK', but only if not ending in 'continue'.
+  function ackObjectsContinue (line) {
+    return !(line.search(/^ACK/) !== -1 && line.search(/continue$/) === -1)
+  }
+
+  // Writes one line to stdin so git-upload-pack can understand.
+  function writeln (line) {
+    if (line) {
+      const len = pad4(line.length + 4 + 1) // Add one for the newline.
+      upload.stdin.write(len + line + '\n')
+    } else {
+      upload.stdin.write('0000')
+    }
+  }
+
+  return upload
+}
+
+async function unpackFile (file, path) {
+  const unpack = spawn('git', ['index-pack', '-v', file, '-o', path])
+  unpack.stderr.pipe(process.stderr)
+
+  return new Promise((resolve, reject) => {
+    unpack.on('exit', (code) => {
+      // These writes are actually necessary for git to finish checkout.
+      process.stdout.write('\n\n')
+      if (code) return reject(code)
+
+      return resolve()
+    })
+  })
+}
+
+async function unpackStream (packStream) {
+  const unpack = spawn('git', ['index-pack', '--stdin', '-v', '--fix-thin'])
+  unpack.stderr.pipe(process.stderr)
+
+  packStream.pipe(unpack.stdin)
+
+  return new Promise((resolve, reject) => {
+    unpack.on('exit', (code) => {
+      // These writes are actually necessary for git to finish checkout.
+      if (code) return reject(code)
+
+      return resolve()
+    })
+  })
+}
+
+module.exports = { lsPromise, uploadPack, unpackFile, unpackStream, createBareRepo, addRemote }