From b600d7b09d3f11b9f1635af67e0e7388cf62189c Mon Sep 17 00:00:00 2001
From: Simon Zolin <s.zolin@adguard.com>
Date: Wed, 11 Mar 2020 19:17:46 +0300
Subject: [PATCH] Merge: - filters: 'enable/disable filter' didn't work

Squashed commit of the following:

commit c4c616162b66f2e89932ac44253ff6bedb8692eb
Merge: 800740da 579177fc
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Wed Mar 11 19:14:27 2020 +0300

    Merge remote-tracking branch 'origin/master' into apply-disable-filter

commit 800740dace018dbe58abc579c06f7c494cdd1c15
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Wed Mar 11 18:40:38 2020 +0300

    improve logic

commit 2aab4fbe658de09cd4c1d0badc178e0ce9e60251
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Wed Mar 11 18:23:14 2020 +0300

    - filters: 'disable filter' didn't work
---
 home/control_filtering.go | 28 +++++++++++++++++++++++++---
 home/filter.go            | 18 ++++++++++--------
 2 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/home/control_filtering.go b/home/control_filtering.go
index 73bd9ca8..d78badf6 100644
--- a/home/control_filtering.go
+++ b/home/control_filtering.go
@@ -185,9 +185,27 @@ func handleFilteringSetURL(w http.ResponseWriter, r *http.Request) {
 	}
 
 	onConfigModified()
-	if (status&(statusURLChanged|statusEnabledChanged)) != 0 && fj.Data.Enabled {
+	restart := false
+	if (status & statusEnabledChanged) != 0 {
+		// we must add or remove filter rules
+		restart = true
+	}
+	if (status&statusUpdateRequired) != 0 && fj.Data.Enabled {
 		// download new filter and apply its rules
-		_, _ = refreshFilters(fj.Whitelist, true)
+		flags := FilterRefreshBlocklists
+		if fj.Whitelist {
+			flags = FilterRefreshAllowlists
+		}
+		nUpdated, _ := refreshFilters(flags, true)
+		// if at least 1 filter has been updated, refreshFilters() restarts the filtering automatically
+		// if not - we restart the filtering ourselves
+		restart = false
+		if nUpdated == 0 {
+			restart = true
+		}
+	}
+	if restart {
+		enableFilters(true)
 	}
 }
 
@@ -226,7 +244,11 @@ func handleFilteringRefresh(w http.ResponseWriter, r *http.Request) {
 	}
 
 	Context.controlLock.Unlock()
-	resp.Updated, err = refreshFilters(req.White, false)
+	flags := FilterRefreshBlocklists
+	if req.White {
+		flags = FilterRefreshAllowlists
+	}
+	resp.Updated, err = refreshFilters(flags|FilterRefreshForce, false)
 	Context.controlLock.Lock()
 	if err != nil {
 		httpError(w, http.StatusInternalServerError, "%s", err)
diff --git a/home/filter.go b/home/filter.go
index d5791ef3..f9770ca3 100644
--- a/home/filter.go
+++ b/home/filter.go
@@ -78,6 +78,7 @@ const (
 	statusEnabledChanged = 2
 	statusURLChanged     = 4
 	statusURLExists      = 8
+	statusUpdateRequired = 0x10
 )
 
 // Update properties for a filter specified by its URL
@@ -103,13 +104,15 @@ func filterSetProperties(url string, newf filter, whitelist bool) int {
 		f.Name = newf.Name
 
 		if f.URL != newf.URL {
-			r |= statusURLChanged
+			r |= statusURLChanged | statusUpdateRequired
 			if filterExistsNoLock(newf.URL) {
 				return statusURLExists
 			}
 			f.URL = newf.URL
 			f.unload()
 			f.LastUpdated = time.Time{}
+			f.checksum = 0
+			f.RulesCount = 0
 		}
 
 		if f.Enabled != newf.Enabled {
@@ -121,8 +124,10 @@ func filterSetProperties(url string, newf filter, whitelist bool) int {
 					if e != nil {
 						// This isn't a fatal error,
 						//  because it may occur when someone removes the file from disk.
-						// In this case the periodic update task will try to download the file.
 						f.LastUpdated = time.Time{}
+						f.checksum = 0
+						f.RulesCount = 0
+						r |= statusUpdateRequired
 					}
 				}
 			} else {
@@ -257,20 +262,17 @@ func periodicallyRefreshFilters() {
 }
 
 // Refresh filters
+// flags: FilterRefresh*
 // important:
 //  TRUE: ignore the fact that we're currently updating the filters
-func refreshFilters(whitelist bool, important bool) (int, error) {
+func refreshFilters(flags int, important bool) (int, error) {
 	set := atomic.CompareAndSwapUint32(&refreshStatus, 0, 1)
 	if !important && !set {
 		return 0, fmt.Errorf("Filters update procedure is already running")
 	}
 
 	refreshLock.Lock()
-	flags := FilterRefreshBlocklists
-	if whitelist {
-		flags = FilterRefreshAllowlists
-	}
-	nUpdated, _ := refreshFiltersIfNecessary(flags | FilterRefreshForce)
+	nUpdated, _ := refreshFiltersIfNecessary(flags)
 	refreshLock.Unlock()
 	refreshStatus = 0
 	return nUpdated, nil