From 730b66b6520f263af16f555d1d7be51205a8e51d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B8rn=20Erik=20Pedersen?=
 <bjorn.erik.pedersen@gmail.com>
Date: Wed, 4 Apr 2018 09:29:59 +0200
Subject: [PATCH] commands: Handle mass content etc. edits in server mode

Fixes #4563
---
 Gopkg.lock             |  8 +++++++-
 Gopkg.toml             |  4 ++++
 commands/commandeer.go | 17 ++++++++++++++++-
 commands/hugo.go       | 25 ++++++++++++++++++-------
 4 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/Gopkg.lock b/Gopkg.lock
index 6b96deb67..90a1c9965 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -57,6 +57,12 @@
   ]
   revision = "85c342e3e3d715ad780edd0ba8728161e99cce24"
 
+[[projects]]
+  branch = "master"
+  name = "github.com/bep/debounce"
+  packages = ["."]
+  revision = "4d3a5ad34e592abc468ed5c6b2a23fcca372ebcd"
+
 [[projects]]
   branch = "master"
   name = "github.com/bep/gitmap"
@@ -424,6 +430,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "edb250b53926de21df1740c379c76351b7e9b110c96a77078a10ba69bf31a2d4"
+  inputs-digest = "49464f23053ef206ad23f65c511943ef50f188a1d0023db3ac5223051a3bba78"
   solver-name = "gps-cdcl"
   solver-version = 1
diff --git a/Gopkg.toml b/Gopkg.toml
index e14d6dc00..573a575ef 100644
--- a/Gopkg.toml
+++ b/Gopkg.toml
@@ -145,3 +145,7 @@
 [[constraint]]
   name = "github.com/sanity-io/litter"
   version = "1.1.0"
+
+[[constraint]]
+  branch = "master"
+  name = "github.com/bep/debounce"
diff --git a/commands/commandeer.go b/commands/commandeer.go
index e96c97814..f7ac93efa 100644
--- a/commands/commandeer.go
+++ b/commands/commandeer.go
@@ -17,6 +17,7 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 
 	"github.com/spf13/cobra"
 
@@ -26,6 +27,7 @@ import (
 
 	"github.com/gohugoio/hugo/hugolib"
 
+	"github.com/bep/debounce"
 	"github.com/gohugoio/hugo/common/types"
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/helpers"
@@ -51,6 +53,9 @@ type commandeer struct {
 	// We can do this only once.
 	fsCreate sync.Once
 
+	// Used in cases where we get flooded with events in server mode.
+	debounce func(f func())
+
 	serverPorts []int
 	languages   helpers.Languages
 
@@ -90,10 +95,20 @@ func (c *commandeer) initFs(fs *hugofs.Fs) error {
 
 func newCommandeer(running bool, doWithCommandeer func(c *commandeer) error, subCmdVs ...*cobra.Command) (*commandeer, error) {
 
+	var rebuildDebouncer func(f func())
+	if running {
+		// The time value used is tested with mass content replacements in a fairly big Hugo site.
+		// It is better to wait for some seconds in those cases rather than get flooded
+		// with rebuilds.
+		rebuildDebouncer, _ = debounce.New(4 * time.Second)
+	}
+
 	c := &commandeer{
 		doWithCommandeer: doWithCommandeer,
 		subCmdVs:         append([]*cobra.Command{hugoCmdV}, subCmdVs...),
-		visitedURLs:      types.NewEvictingStringQueue(10)}
+		visitedURLs:      types.NewEvictingStringQueue(10),
+		debounce:         rebuildDebouncer,
+	}
 
 	return c, c.loadConfig(running)
 }
diff --git a/commands/hugo.go b/commands/hugo.go
index ba8c0aef4..d0894a11a 100644
--- a/commands/hugo.go
+++ b/commands/hugo.go
@@ -851,6 +851,16 @@ func (c *commandeer) rebuildSites(events []fsnotify.Event) error {
 	return Hugo.Build(hugolib.BuildCfg{RecentlyVisited: visited}, events...)
 }
 
+func (c *commandeer) fullRebuild() {
+	if err := c.loadConfig(true); err != nil {
+		jww.ERROR.Println("Failed to reload config:", err)
+	} else if err := c.recreateAndBuildSites(true); err != nil {
+		jww.ERROR.Println(err)
+	} else if !buildWatch && !c.Cfg.GetBool("disableLiveReload") {
+		livereload.ForceRefresh()
+	}
+}
+
 // newWatcher creates a new watcher to watch filesystem events.
 func (c *commandeer) newWatcher(dirList ...string) (*watcher.Batcher, error) {
 	if runtime.GOOS == "darwin" {
@@ -887,6 +897,13 @@ func (c *commandeer) newWatcher(dirList ...string) (*watcher.Batcher, error) {
 		for {
 			select {
 			case evs := <-watcher.Events:
+				if len(evs) > 50 {
+					// This is probably a mass edit of the content dir.
+					// Schedule a full rebuild for when it slows down.
+					c.debounce(c.fullRebuild)
+					continue
+				}
+
 				c.Logger.INFO.Println("Received System Events:", evs)
 
 				staticEvents := []fsnotify.Event{}
@@ -900,13 +917,7 @@ func (c *commandeer) newWatcher(dirList ...string) (*watcher.Batcher, error) {
 							continue
 						}
 						// Config file changed. Need full rebuild.
-						if err := c.loadConfig(true); err != nil {
-							jww.ERROR.Println("Failed to reload config:", err)
-						} else if err := c.recreateAndBuildSites(true); err != nil {
-							jww.ERROR.Println(err)
-						} else if !buildWatch && !c.Cfg.GetBool("disableLiveReload") {
-							livereload.ForceRefresh()
-						}
+						c.fullRebuild()
 						break
 					}