Pull request: all: imp code, err handling

Closes #2571.

Squashed commit of the following:

commit a5b50ee011a995f4ab3d93314acd6f0ca82d99cf
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Mar 15 14:05:25 2021 +0300

    all: imp code

commit bc610f8f438549e8c6b04c8a213b5422dda2aff5
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Fri Mar 12 20:00:14 2021 +0300

    all: imp code, err handling

internal/querylog/http.go

@@ -8,8 +8,6 @@ import (
 	"strconv"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
-
 	"github.com/AdguardTeam/golibs/jsonutil"
 	"github.com/AdguardTeam/golibs/log"
 )
@@ -127,6 +125,17 @@ func getDoubleQuotesEnclosedValue(s *string) bool {
 	return false
 }
 
+// inStr checks if string is in the slice of strings.
+func inStr(strs []string, str string) (ok bool) {
+	for _, s := range strs {
+		if s == str {
+			return true
+		}
+	}
+
+	return false
+}
+
 // parseSearchCriteria - parses "searchCriteria" from the specified query parameter
 func (l *queryLog) parseSearchCriteria(q url.Values, name string, ct criteriaType) (bool, searchCriteria, error) {
 	val := q.Get(name)
@@ -142,7 +151,7 @@ func (l *queryLog) parseSearchCriteria(q url.Values, name string, ct criteriaTyp
 		c.strict = true
 	}
 
-	if ct == ctFilteringStatus && !util.ContainsString(filteringStatusValues, c.value) {
+	if ct == ctFilteringStatus && !inStr(filteringStatusValues, c.value) {
 		return false, c, fmt.Errorf("invalid value %s", c.value)
 	}
 

internal/querylog/qlogreader.go

@@ -4,8 +4,10 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 
 	"github.com/AdguardTeam/AdGuardHome/internal/agherr"
+	"github.com/AdguardTeam/golibs/log"
 )
 
 // QLogReader allows reading from multiple query log files in the reverse order.
@@ -30,8 +32,16 @@ func NewQLogReader(files []string) (*QLogReader, error) {
 	for _, f := range files {
 		q, err := NewQLogFile(f)
 		if err != nil {
-			// Close what we've already opened
-			_ = closeQFiles(qFiles)
+			if errors.Is(err, os.ErrNotExist) {
+				continue
+			}
+
+			// Close what we've already opened.
+			cerr := closeQFiles(qFiles)
+			if cerr != nil {
+				log.Debug("querylog: closing files: %s", cerr)
+			}
+
 			return nil, err
 		}
 

internal/querylog/search.go

@@ -5,7 +5,6 @@ import (
 	"sort"
 	"time"
 
-	"github.com/AdguardTeam/AdGuardHome/internal/util"
 	"github.com/AdguardTeam/golibs/log"
 )
 
@@ -87,9 +86,15 @@ func (l *queryLog) searchFiles(params *searchParams) ([]*logEntry, time.Time, in
 	entries := make([]*logEntry, 0)
 	oldest := time.Time{}
 
-	r, err := l.openReader()
+	files := []string{
+		l.logFile + ".1",
+		l.logFile,
+	}
+
+	r, err := NewQLogReader(files)
 	if err != nil {
-		log.Error("Failed to open qlog reader: %v", err)
+		log.Error("querylog: failed to open qlog reader: %s", err)
+
 		return entries, oldest, 0
 	}
 	defer r.Close()
@@ -174,17 +179,3 @@ func (l *queryLog) readNextEntry(r *QLogReader, params *searchParams) (*logEntry
 
 	return &entry, timestamp, nil
 }
-
-// openReader - opens QLogReader instance
-func (l *queryLog) openReader() (*QLogReader, error) {
-	files := make([]string, 0)
-
-	if util.FileExists(l.logFile + ".1") {
-		files = append(files, l.logFile+".1")
-	}
-	if util.FileExists(l.logFile) {
-		files = append(files, l.logFile)
-	}
-
-	return NewQLogReader(files)
-}