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-rw-r--r--src/internal/profile/prune.go97
1 files changed, 97 insertions, 0 deletions
diff --git a/src/internal/profile/prune.go b/src/internal/profile/prune.go
new file mode 100644
index 0000000..1924fad
--- /dev/null
+++ b/src/internal/profile/prune.go
@@ -0,0 +1,97 @@
+// 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 remove frames from profiles.
+
+package profile
+
+import (
+ "fmt"
+ "regexp"
+)
+
+// Prune removes all nodes beneath a node matching dropRx, and not
+// matching keepRx. If the root node of a Sample matches, the sample
+// will have an empty stack.
+func (p *Profile) Prune(dropRx, keepRx *regexp.Regexp) {
+ prune := make(map[uint64]bool)
+ pruneBeneath := make(map[uint64]bool)
+
+ for _, loc := range p.Location {
+ var i int
+ for i = len(loc.Line) - 1; i >= 0; i-- {
+ if fn := loc.Line[i].Function; fn != nil && fn.Name != "" {
+ funcName := fn.Name
+ // Account for leading '.' on the PPC ELF v1 ABI.
+ if funcName[0] == '.' {
+ funcName = funcName[1:]
+ }
+ if dropRx.MatchString(funcName) {
+ if keepRx == nil || !keepRx.MatchString(funcName) {
+ break
+ }
+ }
+ }
+ }
+
+ if i >= 0 {
+ // Found matching entry to prune.
+ pruneBeneath[loc.ID] = true
+
+ // Remove the matching location.
+ if i == len(loc.Line)-1 {
+ // Matched the top entry: prune the whole location.
+ prune[loc.ID] = true
+ } else {
+ loc.Line = loc.Line[i+1:]
+ }
+ }
+ }
+
+ // Prune locs from each Sample
+ for _, sample := range p.Sample {
+ // Scan from the root to the leaves to find the prune location.
+ // Do not prune frames before the first user frame, to avoid
+ // pruning everything.
+ foundUser := false
+ for i := len(sample.Location) - 1; i >= 0; i-- {
+ id := sample.Location[i].ID
+ if !prune[id] && !pruneBeneath[id] {
+ foundUser = true
+ continue
+ }
+ if !foundUser {
+ continue
+ }
+ if prune[id] {
+ sample.Location = sample.Location[i+1:]
+ break
+ }
+ if pruneBeneath[id] {
+ sample.Location = sample.Location[i:]
+ break
+ }
+ }
+ }
+}
+
+// RemoveUninteresting prunes and elides profiles using built-in
+// tables of uninteresting function names.
+func (p *Profile) RemoveUninteresting() error {
+ var keep, drop *regexp.Regexp
+ var err error
+
+ if p.DropFrames != "" {
+ if drop, err = regexp.Compile("^(" + p.DropFrames + ")$"); err != nil {
+ return fmt.Errorf("failed to compile regexp %s: %v", p.DropFrames, err)
+ }
+ if p.KeepFrames != "" {
+ if keep, err = regexp.Compile("^(" + p.KeepFrames + ")$"); err != nil {
+ return fmt.Errorf("failed to compile regexp %s: %v", p.KeepFrames, err)
+ }
+ }
+ p.Prune(drop, keep)
+ }
+ return nil
+}