Factored out matching lists of regular expressions.

cmd/csaf_downloader/config.go

@@ -9,11 +9,9 @@
 package main
 
 import (
-	"fmt"
-	"log"
 	"net/http"
-	"regexp"
 
+	"github.com/csaf-poc/csaf_distribution/v2/internal/filter"
 	"github.com/csaf-poc/csaf_distribution/v2/internal/models"
 	"github.com/csaf-poc/csaf_distribution/v2/internal/options"
 )
@@ -43,7 +41,7 @@ type config struct {
 
 	Config string `short:"c" long:"config" description:"Path to config TOML file" value-name:"TOML-FILE" toml:"-"`
 
-	ignorePattern []*regexp.Regexp
+	ignorePattern filter.PatternMatcher
 }
 
 // configPaths are the potential file locations of the config file.
@@ -79,27 +77,16 @@ func parseArgsConfig() ([]string, *config, error) {
 
 // ignoreFile returns true if the given URL should not be downloaded.
 func (cfg *config) ignoreURL(u string) bool {
-	for _, expr := range cfg.ignorePattern {
-		if expr.MatchString(u) {
-			return true
-		}
-	}
-	return false
+	return cfg.ignorePattern.Matches(u)
 }
 
 // compileIgnorePatterns compiles the configure patterns to be ignored.
 func (cfg *config) compileIgnorePatterns() error {
-	cfg.ignorePattern = make([]*regexp.Regexp, 0, len(cfg.IgnorePattern))
-	for _, pattern := range cfg.IgnorePattern {
-		expr, err := regexp.Compile(pattern)
-		if err != nil {
-			return fmt.Errorf("invalid ignorepattern: %w", err)
-		}
-		if cfg.Verbose {
-			log.Printf("ignore advisories containing pattern %q\n", expr)
-		}
-		cfg.ignorePattern = append(cfg.ignorePattern, expr)
+	pm, err := filter.NewPatternMatcher(cfg.IgnorePattern)
+	if err != nil {
+		return err
 	}
+	cfg.ignorePattern = pm
 	return nil
 }
 

internal/filter/filter.go

@@ -0,0 +1,42 @@
+// This file is Free Software under the MIT License
+// without warranty, see README.md and LICENSES/MIT.txt for details.
+//
+// SPDX-License-Identifier: MIT
+//
+// SPDX-FileCopyrightText: 2023 German Federal Office for Information Security (BSI) <https://www.bsi.bund.de>
+// Software-Engineering: 2023 Intevation GmbH <https://intevation.de>
+
+// Package filter implements helps to filter advisories.
+package filter
+
+import (
+	"fmt"
+	"regexp"
+)
+
+// PatternMatcher is a list of regular expressions.
+type PatternMatcher []*regexp.Regexp
+
+// NewPatternMatcher compiles a new list of regular expression from
+// a given list of strings.
+func NewPatternMatcher(patterns []string) (PatternMatcher, error) {
+	pm := make(PatternMatcher, 0, len(patterns))
+	for _, pattern := range patterns {
+		expr, err := regexp.Compile(pattern)
+		if err != nil {
+			return nil, fmt.Errorf("invalid ignore pattern: %w", err)
+		}
+		pm = append(pm, expr)
+	}
+	return pm, nil
+}
+
+// Matches returns true if the given string matches any of the expressions.
+func (pm PatternMatcher) Matches(s string) bool {
+	for _, expr := range pm {
+		if expr.MatchString(s) {
+			return true
+		}
+	}
+	return false
+}