chore(grep): do not cut words in excerpt

cli/grep.go

@@ -11,6 +11,8 @@ import (
 	thisS3 "github.com/dabdada/s3-grep/s3"
 )
 
+var MAX_EXCERPT_LENGTH = 120
+
 type grepResult struct {
 	Key     string
 	LineNum int
@@ -40,7 +42,7 @@ func Grep(session *config.AWSSession, bucketName string, query string, ignoreCas
 	for {
 		select {
 		case result := <-results:
-			fmt.Printf("s3://%s/%s %s:%d\n", bucketName, result.Key, result.Excerpt, result.LineNum)
+			fmt.Printf("s3://%s/%s %d:%s\n", bucketName, result.Key, result.LineNum, result.Excerpt)
 		case i := <-done:
 			finished += i
 		default:
@@ -95,14 +97,36 @@ func grepInObjectContent(session *config.AWSSession, bucketName string, objects
 	done <- 1
 }
 
-// Get a small Excerpt of a byte array
+// Get a Excerpt of a byte array
 //
-// 10 chars before and after the substring
+// If the line is not MAX_EXCERPT_LENGTH long, the whole text will be returned.
+// Otherwise a 120 char excerpt is returned.
 func getContentExcerpt(text []byte, query []byte) []byte {
-	queryLength := float64(len(query))
-	index := float64(bytes.Index(text, query))
-	from := int(math.Max(index-10, 0))
-	to := int(math.Min(float64(index+queryLength+ 10), float64(len(text))))
+	textLenght := len(text)
+	if textLenght <= MAX_EXCERPT_LENGTH {
+		return text
+	}
+	queryLength := len(query)
+	excerptLengthLeftAndRight := (MAX_EXCERPT_LENGTH - queryLength) / 2
+	index := bytes.Index(text, query)
+	from := int(math.Max(float64(index-excerptLengthLeftAndRight), 0))
+
+	// Do not cut in the middle of words.
+	if text[from] == byte(' ') {
+		from++
+	} else if from != 0 {
+		from = bytes.Index(text[from:textLenght], []byte(" ")) + 1 + from
+	}
+
+	to := int(math.Min(float64(index+queryLength+excerptLengthLeftAndRight), float64(textLenght)))
+	if to != textLenght {
+		offset := bytes.Index(text[to:textLenght], []byte(" "))
+		if offset < 0 {
+			to = textLenght
+		} else {
+			to += offset
+		}
+	}
 
 	return text[from:to]
 }

cli/grep_test.go

@@ -159,22 +159,34 @@ func TestGetContentExcerpt(t *testing.T) {
 	}{
 		{"starts with query", []byte("someThing"), []byte("some"), []byte("someThing")},
 		{
-			"query in the middle but not enough chars before",
-			[]byte("someThing"),
-			[]byte("Thing"),
-			[]byte("someThing"),
+			"query in the middle but not more than MAX_EXCERPT_LENGTH chars in text",
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge"),
+			[]byte("dock"),
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge"),
 		},
 		{
-			"query in the middle not enough chars to the left and right",
-			[]byte("someThing"),
-			[]byte("meT"),
-			[]byte("someThing"),
+			"query in the middle not enough chars to the left",
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost loaded to the gunwalls"),
+			[]byte("nipper"),
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge"),
+		},
+		{
+			"query in the middle not enough chars to the right",
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost loaded to the gunwalls"),
+			[]byte("barkadeer"),
+			[]byte("Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost loaded to the gunwalls"),
 		},
 		{
 			"more than enough chars right and left of the query",
-			[]byte("someThingSuperLongAndWeirdOnlyForTesting"),
-			[]byte("Long"),
-			[]byte("ThingSuperLongAndWeirdOn"),
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost loaded to the gunwalls"),
+			[]byte("shot"),
+			[]byte("nipper red ensign execution dock Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost"),
+		},
+		{
+			"more than enough chars right and left of the query, find a space in from index",
+			[]byte("Bounty tackle nipper red ensign execution dock Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost loaded to the gunwalls"),
+			[]byte("even"),
+			[]byte("execution dock Sail ho spirits hail-shot scourge of the seven seas barkadeer booty keel hands provost loaded to the gunwalls"),
 		},
 	}
 
@@ -184,7 +196,7 @@ func TestGetContentExcerpt(t *testing.T) {
 			actual := getContentExcerpt(tt.text, tt.query)
 
 			if !bytes.Equal(tt.expected, actual) {
-				t.Errorf("expected excerpt is '%s' but actual was %s", tt.expected, actual)
+				t.Errorf("expected excerpt is '%s' but actual was '%s'", tt.expected, actual)
 			}
 		})
 	}