From 775e3d9e5599594d6dac35de777274bc90268bc2 Mon Sep 17 00:00:00 2001
From: David Norton <dgnorton@gmail.com>
Date: Fri, 17 Apr 2015 18:15:55 -0400
Subject: [PATCH] fix #2281: passthru escapes when parsing regex

---
 CHANGELOG.md             |  3 ++-
 influxql/scanner.go      | 24 ++++++++++++++++--------
 influxql/scanner_test.go | 26 ++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 46a9a79e0d..5706230d8b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,13 +5,14 @@
 - [#2469](https://github.com/influxdb/influxdb/pull/2469): Reduce default max topic size from 1GB to 50MB.
 
 ### Bugfixes
-- [#2446] (https://github.com/influxdb/influxdb/pull/2446): Correctly count number of queries executed. Thanks @neonstalwart
+- [#2446](https://github.com/influxdb/influxdb/pull/2446): Correctly count number of queries executed. Thanks @neonstalwart
 - [#2452](https://github.com/influxdb/influxdb/issues/2452): Fix panic with shard stats on multiple clusters
 - [#2453](https://github.com/influxdb/influxdb/pull/2453): Do not require snapshot on Log.WriteEntriesTo().
 - [#2460](https://github.com/influxdb/influxdb/issues/2460): Collectd input should use "value" for fields values. Fixes 2412. Thanks @josh-padnick
 - [#2465](https://github.com/influxdb/influxdb/pull/2465): HTTP response logging paniced with chunked requests. Thanks @Jackkoz
 - [#2475](https://github.com/influxdb/influxdb/pull/2475): RLock server when checking if shards groups are required during write.
 - [#2471](https://github.com/influxdb/influxdb/issues/2471): Function calls normalized to be lower case. Fixes percentile not working when called uppercase. Thanks @neonstalwart
+- [#2281](https://github.com/influxdb/influxdb/issues/2281): Fix Bad Escape error when parsing regex
 
 ## v0.9.0-rc28 [04-27-2015]
 
diff --git a/influxql/scanner.go b/influxql/scanner.go
index 8ec1aa1100..27bcf414fb 100644
--- a/influxql/scanner.go
+++ b/influxql/scanner.go
@@ -183,7 +183,7 @@ func (s *Scanner) ScanRegex() (tok Token, pos Pos, lit string) {
 	// Valid escape chars.
 	escapes := map[rune]rune{'/': '/'}
 
-	b, err := ScanDelimited(s.r, start, end, escapes)
+	b, err := ScanDelimited(s.r, start, end, escapes, true)
 
 	if err == errBadEscape {
 		_, pos = s.r.curr()
@@ -443,7 +443,7 @@ func (r *reader) curr() (ch rune, pos Pos) {
 // eof is a marker code point to signify that the reader can't read any more.
 const eof = rune(0)
 
-func ScanDelimited(r io.RuneScanner, start, end rune, escapes map[rune]rune) ([]byte, error) {
+func ScanDelimited(r io.RuneScanner, start, end rune, escapes map[rune]rune, escapesPassThru bool) ([]byte, error) {
 	// Scan start delimiter.
 	if ch, _, err := r.ReadRune(); err != nil {
 		return nil, err
@@ -468,15 +468,23 @@ func ScanDelimited(r io.RuneScanner, start, end rune, escapes map[rune]rune) ([]
 				return nil, err
 			}
 
-			r, ok := escapes[ch1]
+			c, ok := escapes[ch1]
 			if !ok {
-				buf.Reset()
-				_, _ = buf.WriteRune(ch0)
-				_, _ = buf.WriteRune(ch1)
-				return buf.Bytes(), errBadEscape
+				if escapesPassThru {
+					// Unread ch1 (char after the \)
+					_ = r.UnreadRune()
+					// Write ch0 (\) to the output buffer.
+					_, _ = buf.WriteRune(ch0)
+					continue
+				} else {
+					buf.Reset()
+					_, _ = buf.WriteRune(ch0)
+					_, _ = buf.WriteRune(ch1)
+					return buf.Bytes(), errBadEscape
+				}
 			}
 
-			_, _ = buf.WriteRune(r)
+			_, _ = buf.WriteRune(c)
 		} else {
 			_, _ = buf.WriteRune(ch0)
 		}
diff --git a/influxql/scanner_test.go b/influxql/scanner_test.go
index e3a03a3532..ab0aab2e4f 100644
--- a/influxql/scanner_test.go
+++ b/influxql/scanner_test.go
@@ -258,3 +258,29 @@ func TestScanString(t *testing.T) {
 		}
 	}
 }
+
+// Test scanning regex
+func TestScanRegex(t *testing.T) {
+	var tests = []struct {
+		in  string
+		tok influxql.Token
+		lit string
+		err string
+	}{
+		{in: `/^payments\./`, tok: influxql.REGEX, lit: `^payments\.`},
+		{in: `/foo\/bar/`, tok: influxql.REGEX, lit: `foo/bar`},
+		{in: `/foo\\/bar/`, tok: influxql.REGEX, lit: `foo\/bar`},
+		{in: `/foo\\bar/`, tok: influxql.REGEX, lit: `foo\\bar`},
+	}
+
+	for i, tt := range tests {
+		s := influxql.NewScanner(strings.NewReader(tt.in))
+		tok, _, lit := s.ScanRegex()
+		if tok != tt.tok {
+			t.Errorf("%d. %s: error:\n\texp=%s\n\tgot=%s\n", i, tt.in, tt.tok.String(), tok.String())
+		}
+		if lit != tt.lit {
+			t.Errorf("%d. %s: error:\n\texp=%s\n\tgot=%s\n", i, tt.in, tt.lit, lit)
+		}
+	}
+}