From ec99001269860e7c9d9ae7f3d4fc38ebdd59428e Mon Sep 17 00:00:00 2001
From: Ruipeng Zhang <ppoffice@users.noreply.github.com>
Date: Tue, 20 Aug 2019 11:00:20 -0400
Subject: [PATCH] feat(generator): allow limit parallel generation (#3665)

---
 lib/plugins/console/generate.js  | 16 +++++++++-------
 lib/plugins/console/index.js     |  3 ++-
 test/scripts/console/generate.js |  4 ++++
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/lib/plugins/console/generate.js b/lib/plugins/console/generate.js
index 729d7b2aba..ff7e9440cd 100644
--- a/lib/plugins/console/generate.js
+++ b/lib/plugins/console/generate.js
@@ -12,6 +12,7 @@ const { HashStream } = require('hexo-util');
 function generateConsole(args = {}) {
   const force = args.f || args.force;
   const bail = args.b || args.bail;
+  const concurrency = args.c || args.concurrency;
   const { route, log } = this;
   const publicDir = this.public_dir;
   let start = process.hrtime();
@@ -117,17 +118,18 @@ function generateConsole(args = {}) {
 
       throw err;
     }).then(() => {
+      const task = (fn, path) => () => fn(path);
+      const doTask = fn => fn();
       const routeList = route.list();
       const publicFiles = Cache.filter(item => item._id.startsWith('public/')).map(item => item._id.substring(7));
-
-      return Promise.all([
+      const tasks = publicFiles.filter(path => !routeList.includes(path))
+        // Clean files
+        .map(path => task(deleteFile, path))
         // Generate files
-        Promise.map(routeList, generateFile),
+        .concat(routeList.map(path => task(generateFile, path)));
 
-        // Clean files
-        Promise.filter(publicFiles, path => !routeList.includes(path)).map(deleteFile)
-      ]);
-    }).spread(result => {
+      return Promise.all(Promise.map(tasks, doTask, { concurrency: parseFloat(concurrency || 'Infinity') }));
+    }).then(result => {
       const interval = prettyHrtime(process.hrtime(start));
       const count = result.filter(Boolean).length;
 
diff --git a/lib/plugins/console/index.js b/lib/plugins/console/index.js
index ca2142caf4..3a34b7b0fb 100644
--- a/lib/plugins/console/index.js
+++ b/lib/plugins/console/index.js
@@ -25,7 +25,8 @@ module.exports = function(ctx) {
       {name: '-d, --deploy', desc: 'Deploy after generated'},
       {name: '-f, --force', desc: 'Force regenerate'},
       {name: '-w, --watch', desc: 'Watch file changes'},
-      {name: '-b, --bail', desc: 'Raise an error if any unhandled exception is thrown during generation'}
+      {name: '-b, --bail', desc: 'Raise an error if any unhandled exception is thrown during generation'},
+      {name: '-c, --concurrency', desc: 'Maximum number of files to be generated in parallel. Default is infinity'}
     ]
   }, require('./generate'));
 
diff --git a/test/scripts/console/generate.js b/test/scripts/console/generate.js
index 429ee24c1d..4755e87a00 100644
--- a/test/scripts/console/generate.js
+++ b/test/scripts/console/generate.js
@@ -231,4 +231,8 @@ describe('generate', () => {
       });
     });
   });
+
+  it('should generate all files even when concurrency is set', () => {
+    return generate({ concurrency: 1 }).then(() => generate({ concurrency: 2 }));
+  });
 });