1// Copyright 2013 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// Package cover provides support for parsing coverage profiles
6// generated by "go test -coverprofile=cover.out".
7package cover // import "golang.org/x/tools/cover"
8
9import (
10	"bufio"
11	"errors"
12	"fmt"
13	"io"
14	"math"
15	"os"
16	"sort"
17	"strconv"
18	"strings"
19)
20
21// Profile represents the profiling data for a specific file.
22type Profile struct {
23	FileName string
24	Mode     string
25	Blocks   []ProfileBlock
26}
27
28// ProfileBlock represents a single block of profiling data.
29type ProfileBlock struct {
30	StartLine, StartCol int
31	EndLine, EndCol     int
32	NumStmt, Count      int
33}
34
35type byFileName []*Profile
36
37func (p byFileName) Len() int           { return len(p) }
38func (p byFileName) Less(i, j int) bool { return p[i].FileName < p[j].FileName }
39func (p byFileName) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
40
41// ParseProfiles parses profile data in the specified file and returns a
42// Profile for each source file described therein.
43func ParseProfiles(fileName string) ([]*Profile, error) {
44	pf, err := os.Open(fileName)
45	if err != nil {
46		return nil, err
47	}
48	defer pf.Close()
49	return ParseProfilesFromReader(pf)
50}
51
52// ParseProfilesFromReader parses profile data from the Reader and
53// returns a Profile for each source file described therein.
54func ParseProfilesFromReader(rd io.Reader) ([]*Profile, error) {
55	// First line is "mode: foo", where foo is "set", "count", or "atomic".
56	// Rest of file is in the format
57	//	encoding/base64/base64.go:34.44,37.40 3 1
58	// where the fields are: name.go:line.column,line.column numberOfStatements count
59	files := make(map[string]*Profile)
60	s := bufio.NewScanner(rd)
61	mode := ""
62	for s.Scan() {
63		line := s.Text()
64		if mode == "" {
65			const p = "mode: "
66			if !strings.HasPrefix(line, p) || line == p {
67				return nil, fmt.Errorf("bad mode line: %v", line)
68			}
69			mode = line[len(p):]
70			continue
71		}
72		fn, b, err := parseLine(line)
73		if err != nil {
74			return nil, fmt.Errorf("line %q doesn't match expected format: %v", line, err)
75		}
76		p := files[fn]
77		if p == nil {
78			p = &Profile{
79				FileName: fn,
80				Mode:     mode,
81			}
82			files[fn] = p
83		}
84		p.Blocks = append(p.Blocks, b)
85	}
86	if err := s.Err(); err != nil {
87		return nil, err
88	}
89	for _, p := range files {
90		sort.Sort(blocksByStart(p.Blocks))
91		// Merge samples from the same location.
92		j := 1
93		for i := 1; i < len(p.Blocks); i++ {
94			b := p.Blocks[i]
95			last := p.Blocks[j-1]
96			if b.StartLine == last.StartLine &&
97				b.StartCol == last.StartCol &&
98				b.EndLine == last.EndLine &&
99				b.EndCol == last.EndCol {
100				if b.NumStmt != last.NumStmt {
101					return nil, fmt.Errorf("inconsistent NumStmt: changed from %d to %d", last.NumStmt, b.NumStmt)
102				}
103				if mode == "set" {
104					p.Blocks[j-1].Count |= b.Count
105				} else {
106					p.Blocks[j-1].Count += b.Count
107				}
108				continue
109			}
110			p.Blocks[j] = b
111			j++
112		}
113		p.Blocks = p.Blocks[:j]
114	}
115	// Generate a sorted slice.
116	profiles := make([]*Profile, 0, len(files))
117	for _, profile := range files {
118		profiles = append(profiles, profile)
119	}
120	sort.Sort(byFileName(profiles))
121	return profiles, nil
122}
123
124// parseLine parses a line from a coverage file.
125// It is equivalent to the regex
126// ^(.+):([0-9]+)\.([0-9]+),([0-9]+)\.([0-9]+) ([0-9]+) ([0-9]+)$
127//
128// However, it is much faster: https://golang.org/cl/179377
129func parseLine(l string) (fileName string, block ProfileBlock, err error) {
130	end := len(l)
131
132	b := ProfileBlock{}
133	b.Count, end, err = seekBack(l, ' ', end, "Count")
134	if err != nil {
135		return "", b, err
136	}
137	b.NumStmt, end, err = seekBack(l, ' ', end, "NumStmt")
138	if err != nil {
139		return "", b, err
140	}
141	b.EndCol, end, err = seekBack(l, '.', end, "EndCol")
142	if err != nil {
143		return "", b, err
144	}
145	b.EndLine, end, err = seekBack(l, ',', end, "EndLine")
146	if err != nil {
147		return "", b, err
148	}
149	b.StartCol, end, err = seekBack(l, '.', end, "StartCol")
150	if err != nil {
151		return "", b, err
152	}
153	b.StartLine, end, err = seekBack(l, ':', end, "StartLine")
154	if err != nil {
155		return "", b, err
156	}
157	fn := l[0:end]
158	if fn == "" {
159		return "", b, errors.New("a FileName cannot be blank")
160	}
161	return fn, b, nil
162}
163
164// seekBack searches backwards from end to find sep in l, then returns the
165// value between sep and end as an integer.
166// If seekBack fails, the returned error will reference what.
167func seekBack(l string, sep byte, end int, what string) (value int, nextSep int, err error) {
168	// Since we're seeking backwards and we know only ASCII is legal for these values,
169	// we can ignore the possibility of non-ASCII characters.
170	for start := end - 1; start >= 0; start-- {
171		if l[start] == sep {
172			i, err := strconv.Atoi(l[start+1 : end])
173			if err != nil {
174				return 0, 0, fmt.Errorf("couldn't parse %q: %v", what, err)
175			}
176			if i < 0 {
177				return 0, 0, fmt.Errorf("negative values are not allowed for %s, found %d", what, i)
178			}
179			return i, start, nil
180		}
181	}
182	return 0, 0, fmt.Errorf("couldn't find a %s before %s", string(sep), what)
183}
184
185type blocksByStart []ProfileBlock
186
187func (b blocksByStart) Len() int      { return len(b) }
188func (b blocksByStart) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
189func (b blocksByStart) Less(i, j int) bool {
190	bi, bj := b[i], b[j]
191	return bi.StartLine < bj.StartLine || bi.StartLine == bj.StartLine && bi.StartCol < bj.StartCol
192}
193
194// Boundary represents the position in a source file of the beginning or end of a
195// block as reported by the coverage profile. In HTML mode, it will correspond to
196// the opening or closing of a <span> tag and will be used to colorize the source
197type Boundary struct {
198	Offset int     // Location as a byte offset in the source file.
199	Start  bool    // Is this the start of a block?
200	Count  int     // Event count from the cover profile.
201	Norm   float64 // Count normalized to [0..1].
202	Index  int     // Order in input file.
203}
204
205// Boundaries returns a Profile as a set of Boundary objects within the provided src.
206func (p *Profile) Boundaries(src []byte) (boundaries []Boundary) {
207	// Find maximum count.
208	max := 0
209	for _, b := range p.Blocks {
210		if b.Count > max {
211			max = b.Count
212		}
213	}
214	// Divisor for normalization.
215	divisor := math.Log(float64(max))
216
217	// boundary returns a Boundary, populating the Norm field with a normalized Count.
218	index := 0
219	boundary := func(offset int, start bool, count int) Boundary {
220		b := Boundary{Offset: offset, Start: start, Count: count, Index: index}
221		index++
222		if !start || count == 0 {
223			return b
224		}
225		if max <= 1 {
226			b.Norm = 0.8 // Profile is in"set" mode; we want a heat map. Use cov8 in the CSS.
227		} else if count > 0 {
228			b.Norm = math.Log(float64(count)) / divisor
229		}
230		return b
231	}
232
233	line, col := 1, 2 // TODO: Why is this 2?
234	for si, bi := 0, 0; si < len(src) && bi < len(p.Blocks); {
235		b := p.Blocks[bi]
236		if b.StartLine == line && b.StartCol == col {
237			boundaries = append(boundaries, boundary(si, true, b.Count))
238		}
239		if b.EndLine == line && b.EndCol == col || line > b.EndLine {
240			boundaries = append(boundaries, boundary(si, false, 0))
241			bi++
242			continue // Don't advance through src; maybe the next block starts here.
243		}
244		if src[si] == '\n' {
245			line++
246			col = 0
247		}
248		col++
249		si++
250	}
251	sort.Sort(boundariesByPos(boundaries))
252	return
253}
254
255type boundariesByPos []Boundary
256
257func (b boundariesByPos) Len() int      { return len(b) }
258func (b boundariesByPos) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
259func (b boundariesByPos) Less(i, j int) bool {
260	if b[i].Offset == b[j].Offset {
261		// Boundaries at the same offset should be ordered according to
262		// their original position.
263		return b[i].Index < b[j].Index
264	}
265	return b[i].Offset < b[j].Offset
266}
267