nodegit/examples/general.js at master · nodegit/nodegit · GitHub

History

317 lines (249 loc) · 12.2 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

const nodegit = require("../");

const path = require("path");

// **nodegit** is a javascript library for node.js that wraps libgit2, a

// pure C implementation of the Git core. It provides an asynchronous

// interface around any functions that do I/O, and a synchronous interface

// around the rest.

// This file is an example of using that API in a real, JS file.

// **libgit2** (for the most part) only implements the core plumbing

// functions, not really the higher level porcelain stuff. For a primer on

// Git Internals that you will need to know to work with Git at this level,

// check out [Chapter 9][pg] of the Pro Git book.

// Nearly, all git operations in the context of a repository.

// To open a repository,

(async () => {

const repo = await nodegit.Repository.open(path.resolve(__dirname, "../.git"));

console.log("Opened repository.");

// ### SHA-1 Value Conversions

// Objects in git (commits, blobs, etc.) are referred to by their SHA value

// **nodegit** uses a simple wrapper around hash values called an `Oid`.

// The oid validates that the SHA is well-formed.

let oid = nodegit.Oid.fromString("c27d9c35e3715539d941254f2ce57042b978c49c");

// Most functions in in **nodegit** that take an oid will also take a

// string, so for example, you can look up a commit by a string SHA or

// an Oid, but any functions that create new SHAs will always return

// an Oid.

// If you have a oid, you can easily get the hex value of the SHA again.

console.log("Sha hex string:", oid.toString());

// ### Working with the Object Database

// **libgit2** provides [direct access][odb] to the object database. The

// object database is where the actual objects are stored in Git. For

// working with raw objects, we'll need to get this structure from the

// repository.

const odb = await repo.odb();

// We can read raw objects directly from the object database if we have

// the oid (SHA) of the object. This allows us to access objects without

// knowing their type and inspect the raw bytes unparsed.

const object = await odb.read(oid);

// A raw object only has three properties - the type (commit, blob, tree

// or tag), the size of the raw data and the raw, unparsed data itself.

// For a commit or tag, that raw data is human readable plain ASCII

// text. For a blob it is just file contents, so it could be text or

// binary data. For a tree it is a special binary format, so it's unlikely

// to be hugely helpful as a raw object.

const data = object.data();

const type = object.type();

const size = object.size();

console.log("Object size and type:", size, type);

console.log("Raw data: ", data.toString().substring(100), "...");

// You can also write raw object data to Git. This is pretty cool because

// it gives you direct access to the key/value properties of Git. Here

// we'll write a new blob object that just contains a simple string.

// Notice that we have to specify the object type.

oid = await odb.write("test data", "test data".length, nodegit.Object.TYPE.BLOB);

// Now that we've written the object, we can check out what SHA1 was

// generated when the object was written to our database.

console.log("Written Object: ", oid.toString());

// ### Object Parsing

// libgit2 has methods to parse every object type in Git so you don't have

// to work directly with the raw data. This is much faster and simpler

// than trying to deal with the raw data yourself.

// #### Commit Parsing

// [Parsing commit objects][pco] is simple and gives you access to all the

// data in the commit - the author (name, email, datetime), committer

// (same), tree, message, encoding and parent(s).

oid = nodegit.Oid.fromString("698c74e817243efe441a5d1f3cbaf3998282ca86");

// Many methods in **nodegit** are asynchronous, because they do file

// or network I/O. By convention, all asynchronous methods are named

// imperatively, like `getCommit`, `open`, `read`, `write`, etc., whereas

// synchronous methods are named nominatively, like `type`, `size`, `name`.

const commit = await repo.getCommit(oid);

// Each of the properties of the commit object are accessible via methods,

// including commonly needed variations, such as `git_commit_time` which

// returns the author time and `git_commit_message` which gives you the

// commit message.

console.log(

"Commit:", commit.message(),

commit.author().name(), commit.date()

);

// Commits can have zero or more parents. The first (root) commit will

// have no parents, most commits will have one (i.e. the commit it was

// based on) and merge commits will have two or more. Commits can

// technically have any number, though it's rare to have more than two.

const parents = await commit.getParents();

for (const parent of parents) {

console.log("Parent:", parent.toString());

}

// #### Writing Commits

// nodegit provides a couple of methods to create commit objects easily as

// well.

const author = nodegit.Signature.now("Scott Chacon",

"schacon@gmail.com");

const committer = nodegit.Signature.now("Scott A Chacon",

"scott@github.com");

// Commit objects need a tree to point to and optionally one or more

// parents. Here we're creating oid objects to create the commit with,

// but you can also use existing ones:

const treeId = nodegit.Oid.fromString(

"4170d10f19600b9cb086504e8e05fe7d863358a2");

const parentId = nodegit.Oid.fromString(

"eebd0ead15d62eaf0ba276da53af43bbc3ce43ab");

let tree = await repo.getTree(treeId);

const parent = await repo.getCommit(parentId);

// Here we actually create the commit object with a single call with all

// the values we need to create the commit. The SHA key is written to

// the `commit_id` variable here.

oid = await repo.createCommit(

null /* do not update the HEAD */,

author,

committer,

"example commit",

tree,

[parent]

);

console.log("New Commit:", oid.toString());

// #### Tag Parsing

// You can parse and create tags with the [tag management API][tm], which

// functions very similarly to the commit lookup, parsing and creation

// methods, since the objects themselves are very similar.

oid = nodegit.Oid.fromString("dcc4aa9fcdaced037434cb149ed3b6eab4d0709d");

const tag = await repo.getTag(oid);

// Now that we have the tag object, we can extract the information it

// generally contains: the target (usually a commit object), the type of

// the target object (usually "commit"), the name ("v1.0"), the tagger (a

// git_signature - name, email, timestamp), and the tag message.

console.log(tag.name(), tag.targetType(), tag.message());

const target = await tag.target();

console.log("Target is commit:", target.isCommit());

// #### Tree Parsing

// A Tree is how Git represents the state of the filesystem

// at a given revision. In general, a tree corresponds to a directory,

// and files in that directory are either files (blobs) or directories.

// [Tree parsing][tp] is a bit different than the other objects, in that

// we have a subtype which is the tree entry. This is not an actual

// object type in Git, but a useful structure for parsing and traversing

// tree entries.

oid = nodegit.Oid.fromString("e1b0c7ea57bfc5e30ec279402a98168a27838ac9");

tree = await repo.getTree(oid);

console.log("Tree Size:", tree.entryCount());

/**

* @param {nodegit.Tree} tree

function dfs(tree) {

const promises = [];

for (const entry of tree.entries()) {

if (entry.isDirectory()) {

promises.push(entry.getTree().then(dfs));

} else if (entry.isFile()) {

console.log("Tree Entry:", entry.name());

}

return Promise.all(promises);

}

await dfs(tree);

// You can also access tree entries by path if you know the path of the

// entry you're looking for.

const entry = await tree.getEntry("example/general.js");

// Entries which are files have blobs associated with them:

let blob = await entry.getBlob();

console.log("Blob size:", blob.rawsize());

// #### Blob Parsing

// The last object type is the simplest and requires the least parsing

// help. Blobs are just file contents and can contain anything, there is

// no structure to it. The main advantage to using the [simple blob

// api][ba] is that when you're creating blobs you don't have to calculate

// the size of the content. There is also a helper for reading a file

// from disk and writing it to the db and getting the oid back so you

// don't have to do all those steps yourself.

oid = nodegit.Oid.fromString("991c06b7b1ec6f939488427e4b41a4fa3e1edd5f");

blob = await repo.getBlob(oid);

// You can access a node.js Buffer with the raw contents

// of the blob directly. Note that this buffer may not

// contain ASCII data for certain blobs (e.g. binary files).

const buffer = blob.content();

// If you know that the blob is UTF-8, however,

console.log("Blob contents:", blob.toString().slice(0, 38));

console.log("Buffer:", buffer.toString().substring(100), "...");

// ### Revwalking

// The libgit2 [revision walking api][rw] provides methods to traverse the

// directed graph created by the parent pointers of the commit objects.

// Since all commits point back to the commit that came directly before

// them, you can walk this parentage as a graph and find all the commits

// that were ancestors of (reachable from) a given starting point. This

// can allow you to create `git log` type functionality.

oid = nodegit.Oid.fromString("698c74e817243efe441a5d1f3cbaf3998282ca86");

// To use the revwalker, create a new walker, tell it how you want to sort

// the output and then push one or more starting points onto the walker.

// If you want to emulate the output of `git log` you would push the SHA

// of the commit that HEAD points to into the walker and then start

// traversing them. You can also "hide" commits that you want to stop at

// or not see any of their ancestors. So if you want to emulate `git log

// branch1..branch2`, you would push the oid of `branch2` and hide the oid

// of `branch1`.

const revWalk = repo.createRevWalk();

revWalk.sorting(

nodegit.Revwalk.SORT.TOPOLOGICAL,

nodegit.Revwalk.SORT.REVERSE

);

revWalk.push(oid);

// Now that we have the starting point pushed onto the walker, we start

// asking for ancestors. It will return them in the sorting order we asked

// for as commit oids. We can then lookup and parse the commits pointed

// at by the returned OID; note that this operation is specially fast

// since the raw contents of the commit object will be cached in memory.

async function walk() {

let oid;

try {

oid = await revWalk.next();

} catch(error) {

if (error.errno !== nodegit.Error.CODE.ITEROVER) {

throw error;

} else {

return;

}

const commit = await repo.getCommit(oid);

console.log("Commit:", commit.toString());

return walk();

}

await walk();

// ### Index File Manipulation

// The [index file API][gi] allows you to read, traverse, update and write

// the Git index file (sometimes thought of as the staging area).

const index = await repo.refreshIndex();

// For each entry in the index, you can get a bunch of information

// including the SHA (oid), path and mode which map to the tree objects

// that are written out. It also has filesystem properties to help

// determine what to inspect for changes (ctime, mtime, dev, ino, uid,

// gid, file_size and flags) All these properties are exported publicly in

// the `IndexEntry` class

for (const entry of index.entries()) {

console.log("Index Entry:", entry.path, entry.mtime.seconds());

}

// ### References

// The [reference API][ref] allows you to list, resolve, create and update

// references such as branches, tags and remote references (everything in

// the .git/refs directory).

const referenceNames = await repo.getReferenceNames(nodegit.Reference.TYPE.ALL);

for (const referenceName of referenceNames) {

const reference = await repo.getReference(referenceName);

if (reference.isConcrete()) {

console.log("Reference:", referenceName, reference.target());

} else if (reference.isSymbolic()) {

console.log("Reference:", referenceName, reference.symbolicTarget());

}

console.log("Done!");

})();

nodegit/examples/general.js at master · nodegit/nodegit · GitHub

Uh oh!

Expand file tree

Breadcrumbs

general.js

Latest commit

History

Breadcrumbs

general.js

File metadata and controls