From 003010f73b21b155be26fc183e29d602d7412ebd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Mierzwa?= <l.mierzwa@gmail.com>
Date: Fri, 5 May 2017 22:36:50 +0100
Subject: [PATCH] Speed up filter matches by re-using global match object

Instead of compiling filter regexp on every filter match pre-compile it and use same instance
---
 filters/filter.go   | 3 +--
 filters/registry.go | 9 +++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/filters/filter.go b/filters/filter.go
index 8d186bc3d..77ccb2c41 100644
--- a/filters/filter.go
+++ b/filters/filter.go
@@ -96,8 +96,7 @@ func NewFilter(expression string) FilterT {
 	// we have "filter=" part, lookup filter that matches
 	for _, fc := range AllFilters {
 		f := fc.Factory()
-		labelRe := regexp.MustCompile("^(?:" + fc.Label + ")$")
-		if !labelRe.MatchString(matched) {
+		if !fc.LabelRe.MatchString(matched) {
 			// filter name doesn't match, keep searching
 			continue
 		}
diff --git a/filters/registry.go b/filters/registry.go
index e8d087cf3..88073ceca 100644
--- a/filters/registry.go
+++ b/filters/registry.go
@@ -1,5 +1,7 @@
 package filters
 
+import "regexp"
+
 const (
 	equalOperator         string = "="
 	notEqualOperator      string = "!="
@@ -29,6 +31,7 @@ var matcherConfig = map[string]matcherT{
 
 type filterConfig struct {
 	Label              string
+	LabelRe            *regexp.Regexp
 	SupportedOperators []string
 	Factory            newFilterFactory
 	Autocomplete       autocompleteFactory
@@ -39,36 +42,42 @@ type filterConfig struct {
 var AllFilters = []filterConfig{
 	filterConfig{
 		Label:              "@status",
+		LabelRe:            regexp.MustCompile("^@status$"),
 		SupportedOperators: []string{equalOperator, notEqualOperator},
 		Factory:            newstatusFilter,
 		Autocomplete:       statusAutocomplete,
 	},
 	filterConfig{
 		Label:              "@age",
+		LabelRe:            regexp.MustCompile("^@age$"),
 		SupportedOperators: []string{lessThanOperator, moreThanOperator},
 		Factory:            newAgeFilter,
 		Autocomplete:       ageAutocomplete,
 	},
 	filterConfig{
 		Label:              "@silence_jira",
+		LabelRe:            regexp.MustCompile("^@silence_jira$"),
 		SupportedOperators: []string{regexpOperator, negativeRegexOperator, equalOperator, notEqualOperator},
 		Factory:            newSilenceJiraFilter,
 		Autocomplete:       sinceJiraIDAutocomplete,
 	},
 	filterConfig{
 		Label:              "@silence_author",
+		LabelRe:            regexp.MustCompile("^@silence_author$"),
 		SupportedOperators: []string{regexpOperator, negativeRegexOperator, equalOperator, notEqualOperator},
 		Factory:            newSilenceAuthorFilter,
 		Autocomplete:       sinceAuthorAutocomplete,
 	},
 	filterConfig{
 		Label:              "@limit",
+		LabelRe:            regexp.MustCompile("^@limit$"),
 		SupportedOperators: []string{equalOperator},
 		Factory:            newLimitFilter,
 		Autocomplete:       limitAutocomplete,
 	},
 	filterConfig{
 		Label:              "[a-zA-Z_][a-zA-Z0-9_]*",
+		LabelRe:            regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$"),
 		SupportedOperators: []string{regexpOperator, negativeRegexOperator, equalOperator, notEqualOperator, lessThanOperator, moreThanOperator},
 		Factory:            newLabelFilter,
 		Autocomplete:       labelAutocomplete,