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// Copyright 2022 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.
package coverage
import (
"encoding/json"
"fmt"
"internal/coverage"
"internal/coverage/calloc"
"internal/coverage/cformat"
"internal/coverage/cmerge"
"internal/coverage/decodecounter"
"internal/coverage/decodemeta"
"internal/coverage/pods"
"io"
"os"
"path/filepath"
"runtime/internal/atomic"
"strings"
"unsafe"
)
// processCoverTestDir is called (via a linknamed reference) from
// testmain code when "go test -cover" is in effect. It is not
// intended to be used other than internally by the Go command's
// generated code.
func processCoverTestDir(dir string, cfile string, cm string, cpkg string) error {
return processCoverTestDirInternal(dir, cfile, cm, cpkg, os.Stdout)
}
// processCoverTestDirInternal is an io.Writer version of processCoverTestDir,
// exposed for unit testing.
func processCoverTestDirInternal(dir string, cfile string, cm string, cpkg string, w io.Writer) error {
cmode := coverage.ParseCounterMode(cm)
if cmode == coverage.CtrModeInvalid {
return fmt.Errorf("invalid counter mode %q", cm)
}
// Emit meta-data and counter data.
ml := getCovMetaList()
if len(ml) == 0 {
// This corresponds to the case where we have a package that
// contains test code but no functions (which is fine). In this
// case there is no need to emit anything.
} else {
if err := emitMetaDataToDirectory(dir, ml); err != nil {
return err
}
if err := emitCounterDataToDirectory(dir); err != nil {
return err
}
}
// Collect pods from test run. For the majority of cases we would
// expect to see a single pod here, but allow for multiple pods in
// case the test harness is doing extra work to collect data files
// from builds that it kicks off as part of the testing.
podlist, err := pods.CollectPods([]string{dir}, false)
if err != nil {
return fmt.Errorf("reading from %s: %v", dir, err)
}
// Open text output file if appropriate.
var tf *os.File
var tfClosed bool
if cfile != "" {
var err error
tf, err = os.Create(cfile)
if err != nil {
return fmt.Errorf("internal error: opening coverage data output file %q: %v", cfile, err)
}
defer func() {
if !tfClosed {
tfClosed = true
tf.Close()
}
}()
}
// Read/process the pods.
ts := &tstate{
cm: &cmerge.Merger{},
cf: cformat.NewFormatter(cmode),
cmode: cmode,
}
// Generate the expected hash string based on the final meta-data
// hash for this test, then look only for pods that refer to that
// hash (just in case there are multiple instrumented executables
// in play). See issue #57924 for more on this.
hashstring := fmt.Sprintf("%x", finalHash)
importpaths := make(map[string]struct{})
for _, p := range podlist {
if !strings.Contains(p.MetaFile, hashstring) {
continue
}
if err := ts.processPod(p, importpaths); err != nil {
return err
}
}
metafilespath := filepath.Join(dir, coverage.MetaFilesFileName)
if _, err := os.Stat(metafilespath); err == nil {
if err := ts.readAuxMetaFiles(metafilespath, importpaths); err != nil {
return err
}
}
// Emit percent.
if err := ts.cf.EmitPercent(w, cpkg, true, true); err != nil {
return err
}
// Emit text output.
if tf != nil {
if err := ts.cf.EmitTextual(tf); err != nil {
return err
}
tfClosed = true
if err := tf.Close(); err != nil {
return fmt.Errorf("closing %s: %v", cfile, err)
}
}
return nil
}
type tstate struct {
calloc.BatchCounterAlloc
cm *cmerge.Merger
cf *cformat.Formatter
cmode coverage.CounterMode
}
// processPod reads coverage counter data for a specific pod.
func (ts *tstate) processPod(p pods.Pod, importpaths map[string]struct{}) error {
// Open meta-data file
f, err := os.Open(p.MetaFile)
if err != nil {
return fmt.Errorf("unable to open meta-data file %s: %v", p.MetaFile, err)
}
defer func() {
f.Close()
}()
var mfr *decodemeta.CoverageMetaFileReader
mfr, err = decodemeta.NewCoverageMetaFileReader(f, nil)
if err != nil {
return fmt.Errorf("error reading meta-data file %s: %v", p.MetaFile, err)
}
newmode := mfr.CounterMode()
if newmode != ts.cmode {
return fmt.Errorf("internal error: counter mode clash: %q from test harness, %q from data file %s", ts.cmode.String(), newmode.String(), p.MetaFile)
}
newgran := mfr.CounterGranularity()
if err := ts.cm.SetModeAndGranularity(p.MetaFile, cmode, newgran); err != nil {
return err
}
// A map to store counter data, indexed by pkgid/fnid tuple.
pmm := make(map[pkfunc][]uint32)
// Helper to read a single counter data file.
readcdf := func(cdf string) error {
cf, err := os.Open(cdf)
if err != nil {
return fmt.Errorf("opening counter data file %s: %s", cdf, err)
}
defer cf.Close()
var cdr *decodecounter.CounterDataReader
cdr, err = decodecounter.NewCounterDataReader(cdf, cf)
if err != nil {
return fmt.Errorf("reading counter data file %s: %s", cdf, err)
}
var data decodecounter.FuncPayload
for {
ok, err := cdr.NextFunc(&data)
if err != nil {
return fmt.Errorf("reading counter data file %s: %v", cdf, err)
}
if !ok {
break
}
// NB: sanity check on pkg and func IDs?
key := pkfunc{pk: data.PkgIdx, fcn: data.FuncIdx}
if prev, found := pmm[key]; found {
// Note: no overflow reporting here.
if err, _ := ts.cm.MergeCounters(data.Counters, prev); err != nil {
return fmt.Errorf("processing counter data file %s: %v", cdf, err)
}
}
c := ts.AllocateCounters(len(data.Counters))
copy(c, data.Counters)
pmm[key] = c
}
return nil
}
// Read counter data files.
for _, cdf := range p.CounterDataFiles {
if err := readcdf(cdf); err != nil {
return err
}
}
// Visit meta-data file.
np := uint32(mfr.NumPackages())
payload := []byte{}
for pkIdx := uint32(0); pkIdx < np; pkIdx++ {
var pd *decodemeta.CoverageMetaDataDecoder
pd, payload, err = mfr.GetPackageDecoder(pkIdx, payload)
if err != nil {
return fmt.Errorf("reading pkg %d from meta-file %s: %s", pkIdx, p.MetaFile, err)
}
ts.cf.SetPackage(pd.PackagePath())
importpaths[pd.PackagePath()] = struct{}{}
var fd coverage.FuncDesc
nf := pd.NumFuncs()
for fnIdx := uint32(0); fnIdx < nf; fnIdx++ {
if err := pd.ReadFunc(fnIdx, &fd); err != nil {
return fmt.Errorf("reading meta-data file %s: %v",
p.MetaFile, err)
}
key := pkfunc{pk: pkIdx, fcn: fnIdx}
counters, haveCounters := pmm[key]
for i := 0; i < len(fd.Units); i++ {
u := fd.Units[i]
// Skip units with non-zero parent (no way to represent
// these in the existing format).
if u.Parent != 0 {
continue
}
count := uint32(0)
if haveCounters {
count = counters[i]
}
ts.cf.AddUnit(fd.Srcfile, fd.Funcname, fd.Lit, u, count)
}
}
}
return nil
}
type pkfunc struct {
pk, fcn uint32
}
func (ts *tstate) readAuxMetaFiles(metafiles string, importpaths map[string]struct{}) error {
// Unmarshall the information on available aux metafiles into
// a MetaFileCollection struct.
var mfc coverage.MetaFileCollection
data, err := os.ReadFile(metafiles)
if err != nil {
return fmt.Errorf("error reading auxmetafiles file %q: %v", metafiles, err)
}
if err := json.Unmarshal(data, &mfc); err != nil {
return fmt.Errorf("error reading auxmetafiles file %q: %v", metafiles, err)
}
// Walk through each available aux meta-file. If we've already
// seen the package path in question during the walk of the
// "regular" meta-data file, then we can skip the package,
// otherwise construct a dummy pod with the single meta-data file
// (no counters) and invoke processPod on it.
for i := range mfc.ImportPaths {
p := mfc.ImportPaths[i]
if _, ok := importpaths[p]; ok {
continue
}
var pod pods.Pod
pod.MetaFile = mfc.MetaFileFragments[i]
if err := ts.processPod(pod, importpaths); err != nil {
return err
}
}
return nil
}
// snapshot returns a snapshot of coverage percentage at a moment of
// time within a running test, so as to support the testing.Coverage()
// function. This version doesn't examine coverage meta-data, so the
// result it returns will be less accurate (more "slop") due to the
// fact that we don't look at the meta data to see how many statements
// are associated with each counter.
func snapshot() float64 {
cl := getCovCounterList()
if len(cl) == 0 {
// no work to do here.
return 0.0
}
tot := uint64(0)
totExec := uint64(0)
for _, c := range cl {
sd := unsafe.Slice((*atomic.Uint32)(unsafe.Pointer(c.Counters)), c.Len)
tot += uint64(len(sd))
for i := 0; i < len(sd); i++ {
// Skip ahead until the next non-zero value.
if sd[i].Load() == 0 {
continue
}
// We found a function that was executed.
nCtrs := sd[i+coverage.NumCtrsOffset].Load()
cst := i + coverage.FirstCtrOffset
if cst+int(nCtrs) > len(sd) {
break
}
counters := sd[cst : cst+int(nCtrs)]
for i := range counters {
if counters[i].Load() != 0 {
totExec++
}
}
i += coverage.FirstCtrOffset + int(nCtrs) - 1
}
}
if tot == 0 {
return 0.0
}
return float64(totExec) / float64(tot)
}