feat(gen:gulp): port changelog code to gulp

[skip ci]

gulpfile.js

@@ -16,6 +16,7 @@ const runSequence = require('run-sequence');
 const merge = require('merge-stream');
 const shell = require('shelljs');
 const ghPages = require('gulp-gh-pages');
+const conventionalChangelog = require('gulp-conventional-changelog');
 
 var watching = false;
 
@@ -194,3 +195,60 @@ gulp.task('gh-pages', () => {
 gulp.task('docs', cb => {
     return runSequence('daux', 'copy_docs_images', 'gh-pages', cb);
 });
+
+let finalizeContext = function(context, writerOpts, commits, keyCommit) {
+    var gitSemverTags = context.gitSemverTags;
+    var commitGroups = context.commitGroups;
+
+    if((!context.currentTag || !context.previousTag) && keyCommit) {
+        var match = /tag:\s*(.+?)[,\)]/gi.exec(keyCommit.gitTags);
+        var currentTag = context.currentTag = context.currentTag || match ? match[1] : null;
+        var index = gitSemverTags.indexOf(currentTag);
+        var previousTag = context.previousTag = gitSemverTags[index + 1];
+
+        if(!previousTag) {
+            if(options.append) {
+              context.previousTag = context.previousTag || commits[0] ? commits[0].hash : null;
+            } else {
+              context.previousTag = context.previousTag || commits[commits.length - 1] ? commits[commits.length - 1].hash : null;
+            }
+        }
+    } else {
+        context.previousTag = context.previousTag || gitSemverTags[0];
+        context.currentTag = context.currentTag || 'v' + context.version;
+    }
+
+    if(typeof context.linkCompare !== 'boolean' && context.previousTag && context.currentTag) {
+        context.linkCompare = true;
+    }
+
+    if(Array.isArray(commitGroups)) {
+        for(var i = 0, commitGroupsLength = commitGroups.length; i < commitGroupsLength; i++) {
+            var commits = commitGroups[i].commits;
+            if(Array.isArray(commits)) {
+                for(var n = 1, commitsLength = commits.length; n < commitsLength; n++) {
+                    var commit = commits[n], prevCommit = commits[n - 1];
+                    if(commit.scope && commit.scope === prevCommit.scope) {
+                        commit.subScope = true;
+                        if(prevCommit.scope && !prevCommit.subScope) {
+                            prevCommit.leadScope = true;
+                        }
+                    }
+                }
+            }
+        }
+    }
+    return context;
+};
+let commitPartial = fs.readFileSync(path.resolve(__dirname, 'task-utils/changelog-templates/commit.hbs')).toString();
+
+gulp.task('changelog', () => {
+  return gulp.src('CHANGELOG.md', {buffer: false})
+    .pipe(conventionalChangelog({
+      preset: 'angular'
+    }, {/*context*/}, {/*git-raw-commits*/}, {/*conventional-commits-parser*/}, {/*conventional-changelog-writer*/
+        finalizeContext,
+        commitPartial
+    }))
+    .pipe(gulp.dest('./'));
+});

package.json

@@ -71,6 +71,7 @@
     "grunt-mocha-test": "^0.12.7",
     "grunt-release": "^0.14.0",
     "gulp": "^3.9.1",
+    "gulp-conventional-changelog": "^1.1.0",
     "gulp-gh-pages": "^0.5.4",
     "gulp-if": "^2.0.1",
     "gulp-mocha": "^3.0.0",