Pull request: querylog: more opt

Updates 1273.

Squashed commit of the following:

commit 167c0b5acaab8a2676de2cea556c861dc0efbc72
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 12 18:12:43 2021 +0300

    querylog: imp naming

commit 5010ad113e46335011a721cbcc9fc9b1fc623722
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Mon Apr 12 17:53:41 2021 +0300

    querylog: more opt

internal/querylog/searchcriterion.go

@@ -0,0 +1,197 @@
+package querylog
+
+import (
+	"strings"
+
+	"github.com/AdguardTeam/AdGuardHome/internal/dnsfilter"
+)
+
+type criterionType int
+
+const (
+	// ctDomainOrClient is for searching by the domain name, the client's IP
+	// address, or the clinet's ID.
+	ctDomainOrClient criterionType = iota
+	// ctFilteringStatus is for searching by the filtering status.
+	//
+	// See (*searchCriterion).ctFilteringStatusCase for details.
+	ctFilteringStatus
+)
+
+const (
+	filteringStatusAll      = "all"
+	filteringStatusFiltered = "filtered" // all kinds of filtering
+
+	filteringStatusBlocked             = "blocked"              // blocked or blocked services
+	filteringStatusBlockedService      = "blocked_services"     // blocked
+	filteringStatusBlockedSafebrowsing = "blocked_safebrowsing" // blocked by safebrowsing
+	filteringStatusBlockedParental     = "blocked_parental"     // blocked by parental control
+	filteringStatusWhitelisted         = "whitelisted"          // whitelisted
+	filteringStatusRewritten           = "rewritten"            // all kinds of rewrites
+	filteringStatusSafeSearch          = "safe_search"          // enforced safe search
+	filteringStatusProcessed           = "processed"            // not blocked, not white-listed entries
+)
+
+// filteringStatusValues -- array with all possible filteringStatus values
+var filteringStatusValues = []string{
+	filteringStatusAll, filteringStatusFiltered, filteringStatusBlocked,
+	filteringStatusBlockedService, filteringStatusBlockedSafebrowsing, filteringStatusBlockedParental,
+	filteringStatusWhitelisted, filteringStatusRewritten, filteringStatusSafeSearch,
+	filteringStatusProcessed,
+}
+
+// searchCriterion is a search criterion that is used to match a record.
+type searchCriterion struct {
+	value         string
+	criterionType criterionType
+	// strict, if true, means that the criterion must be applied to the
+	// whole value rather than the part of it.  That is, equality and not
+	// containment.
+	strict bool
+}
+
+func (c *searchCriterion) ctDomainOrClientCaseStrict(
+	term string,
+	clientID string,
+	name string,
+	host string,
+	ip string,
+) (ok bool) {
+	return strings.EqualFold(host, term) ||
+		strings.EqualFold(clientID, term) ||
+		strings.EqualFold(ip, term) ||
+		strings.EqualFold(name, term)
+}
+
+func (c *searchCriterion) ctDomainOrClientCaseNonStrict(
+	term string,
+	clientID string,
+	name string,
+	host string,
+	ip string,
+) (ok bool) {
+	// TODO(a.garipov): Write a performant, case-insensitive version of
+	// strings.Contains instead of generating garbage.  Or, perhaps in the
+	// future, use a locale-appropriate matcher from golang.org/x/text.
+	clientID = strings.ToLower(clientID)
+	host = strings.ToLower(host)
+	ip = strings.ToLower(ip)
+	name = strings.ToLower(name)
+	term = strings.ToLower(term)
+
+	return strings.Contains(clientID, term) ||
+		strings.Contains(host, term) ||
+		strings.Contains(ip, term) ||
+		strings.Contains(name, term)
+}
+
+// quickMatch quickly checks if the line matches the given search criterion.
+// It returns false if the like doesn't match.  This method is only here for
+// optimisation purposes.
+func (c *searchCriterion) quickMatch(line string, findClient quickMatchClientFunc) (ok bool) {
+	switch c.criterionType {
+	case ctDomainOrClient:
+		host := readJSONValue(line, `"QH":"`)
+		ip := readJSONValue(line, `"IP":"`)
+		clientID := readJSONValue(line, `"CID":"`)
+
+		var name string
+		if cli := findClient(clientID, ip); cli != nil {
+			name = cli.Name
+		}
+
+		if c.strict {
+			return c.ctDomainOrClientCaseStrict(c.value, clientID, name, host, ip)
+		}
+
+		return c.ctDomainOrClientCaseNonStrict(c.value, clientID, name, host, ip)
+	case ctFilteringStatus:
+		// Go on, as we currently don't do quick matches against
+		// filtering statuses.
+		return true
+	default:
+		return true
+	}
+}
+
+// match checks if the log entry matches this search criterion.
+func (c *searchCriterion) match(entry *logEntry) bool {
+	switch c.criterionType {
+	case ctDomainOrClient:
+		return c.ctDomainOrClientCase(entry)
+	case ctFilteringStatus:
+		return c.ctFilteringStatusCase(entry.Result)
+	}
+
+	return false
+}
+
+func (c *searchCriterion) ctDomainOrClientCase(e *logEntry) bool {
+	clientID := e.ClientID
+	host := e.QHost
+
+	var name string
+	if e.client != nil {
+		name = e.client.Name
+	}
+
+	ip := e.IP.String()
+	term := strings.ToLower(c.value)
+	if c.strict {
+		return c.ctDomainOrClientCaseStrict(term, clientID, name, host, ip)
+	}
+
+	return c.ctDomainOrClientCaseNonStrict(term, clientID, name, host, ip)
+}
+
+func (c *searchCriterion) ctFilteringStatusCase(res dnsfilter.Result) bool {
+	switch c.value {
+	case filteringStatusAll:
+		return true
+
+	case filteringStatusFiltered:
+		return res.IsFiltered ||
+			res.Reason.In(
+				dnsfilter.NotFilteredAllowList,
+				dnsfilter.Rewritten,
+				dnsfilter.RewrittenAutoHosts,
+				dnsfilter.RewrittenRule,
+			)
+
+	case filteringStatusBlocked:
+		return res.IsFiltered &&
+			res.Reason.In(dnsfilter.FilteredBlockList, dnsfilter.FilteredBlockedService)
+
+	case filteringStatusBlockedService:
+		return res.IsFiltered && res.Reason == dnsfilter.FilteredBlockedService
+
+	case filteringStatusBlockedParental:
+		return res.IsFiltered && res.Reason == dnsfilter.FilteredParental
+
+	case filteringStatusBlockedSafebrowsing:
+		return res.IsFiltered && res.Reason == dnsfilter.FilteredSafeBrowsing
+
+	case filteringStatusWhitelisted:
+		return res.Reason == dnsfilter.NotFilteredAllowList
+
+	case filteringStatusRewritten:
+		return res.Reason.In(
+			dnsfilter.Rewritten,
+			dnsfilter.RewrittenAutoHosts,
+			dnsfilter.RewrittenRule,
+		)
+
+	case filteringStatusSafeSearch:
+		return res.IsFiltered && res.Reason == dnsfilter.FilteredSafeSearch
+
+	case filteringStatusProcessed:
+		return !res.Reason.In(
+			dnsfilter.FilteredBlockList,
+			dnsfilter.FilteredBlockedService,
+			dnsfilter.NotFilteredAllowList,
+		)
+
+	default:
+		return false
+	}
+}