1 files changed, 157 insertions, 0 deletions
diff --git a/src/cmd/pprof/internal/profile/filter.go b/src/cmd/pprof/internal/profile/filter.go
new file mode 100644
index 000000000..903616aac
--- /dev/null
+++ b/src/cmd/pprof/internal/profile/filter.go
@@ -0,0 +1,157 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Implements methods to filter samples from profiles.
+package profile
+
+import "regexp"
+
+// FilterSamplesByName filters the samples in a profile and only keeps
+// samples where at least one frame matches focus but none match ignore.
+// Returns true is the corresponding regexp matched at least one sample.
+func (p *Profile) FilterSamplesByName(focus, ignore, hide *regexp.Regexp) (fm, im, hm bool) {
+	focusOrIgnore := make(map[uint64]bool)
+	hidden := make(map[uint64]bool)
+	for _, l := range p.Location {
+		if ignore != nil && l.matchesName(ignore) {
+			im = true
+			focusOrIgnore[l.ID] = false
+		} else if focus == nil || l.matchesName(focus) {
+			fm = true
+			focusOrIgnore[l.ID] = true
+		}
+		if hide != nil && l.matchesName(hide) {
+			hm = true
+			l.Line = l.unmatchedLines(hide)
+			if len(l.Line) == 0 {
+				hidden[l.ID] = true
+			}
+		}
+	}
+
+	s := make([]*Sample, 0, len(p.Sample))
+	for _, sample := range p.Sample {
+		if focusedAndNotIgnored(sample.Location, focusOrIgnore) {
+			if len(hidden) > 0 {
+				var locs []*Location
+				for _, loc := range sample.Location {
+					if !hidden[loc.ID] {
+						locs = append(locs, loc)
+					}
+				}
+				if len(locs) == 0 {
+					// Remove sample with no locations (by not adding it to s).
+					continue
+				}
+				sample.Location = locs
+			}
+			s = append(s, sample)
+		}
+	}
+	p.Sample = s
+
+	return
+}
+
+// matchesName returns whether the function name or file in the
+// location matches the regular expression.
+func (loc *Location) matchesName(re *regexp.Regexp) bool {
+	for _, ln := range loc.Line {
+		if fn := ln.Function; fn != nil {
+			if re.MatchString(fn.Name) {
+				return true
+			}
+			if re.MatchString(fn.Filename) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// unmatchedLines returns the lines in the location that do not match
+// the regular expression.
+func (loc *Location) unmatchedLines(re *regexp.Regexp) []Line {
+	var lines []Line
+	for _, ln := range loc.Line {
+		if fn := ln.Function; fn != nil {
+			if re.MatchString(fn.Name) {
+				continue
+			}
+			if re.MatchString(fn.Filename) {
+				continue
+			}
+		}
+		lines = append(lines, ln)
+	}
+	return lines
+}
+
+// focusedAndNotIgnored looks up a slice of ids against a map of
+// focused/ignored locations. The map only contains locations that are
+// explicitly focused or ignored. Returns whether there is at least
+// one focused location but no ignored locations.
+func focusedAndNotIgnored(locs []*Location, m map[uint64]bool) bool {
+	var f bool
+	for _, loc := range locs {
+		if focus, focusOrIgnore := m[loc.ID]; focusOrIgnore {
+			if focus {
+				// Found focused location. Must keep searching in case there
+				// is an ignored one as well.
+				f = true
+			} else {
+				// Found ignored location. Can return false right away.
+				return false
+			}
+		}
+	}
+	return f
+}
+
+// TagMatch selects tags for filtering
+type TagMatch func(key, val string, nval int64) bool
+
+// FilterSamplesByTag removes all samples from the profile, except
+// those that match focus and do not match the ignore regular
+// expression.
+func (p *Profile) FilterSamplesByTag(focus, ignore TagMatch) (fm, im bool) {
+	samples := make([]*Sample, 0, len(p.Sample))
+	for _, s := range p.Sample {
+		focused, ignored := focusedSample(s, focus, ignore)
+		fm = fm || focused
+		im = im || ignored
+		if focused && !ignored {
+			samples = append(samples, s)
+		}
+	}
+	p.Sample = samples
+	return
+}
+
+// focusedTag checks a sample against focus and ignore regexps.
+// Returns whether the focus/ignore regexps match any tags
+func focusedSample(s *Sample, focus, ignore TagMatch) (fm, im bool) {
+	fm = focus == nil
+	for key, vals := range s.Label {
+		for _, val := range vals {
+			if ignore != nil && ignore(key, val, 0) {
+				im = true
+			}
+			if !fm && focus(key, val, 0) {
+				fm = true
+			}
+		}
+	}
+	for key, vals := range s.NumLabel {
+		for _, val := range vals {
+			if ignore != nil && ignore(key, "", val) {
+				im = true
+			}
+			if !fm && focus(key, "", val) {
+				fm = true
+			}
+		}
+	}
+	return fm, im
+}