1 files changed, 109 insertions, 0 deletions
diff --git a/src/cmd/covdata/merge.go b/src/cmd/covdata/merge.go
new file mode 100644
index 0000000..225861d
--- /dev/null
+++ b/src/cmd/covdata/merge.go
@@ -0,0 +1,109 @@
+// 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 main
+
+// This file contains functions and apis to support the "merge"
+// subcommand of "go tool covdata".
+
+import (
+	"flag"
+	"fmt"
+	"internal/coverage"
+	"internal/coverage/decodecounter"
+	"internal/coverage/decodemeta"
+	"internal/coverage/pods"
+	"os"
+)
+
+var outdirflag *string
+var pcombineflag *bool
+
+func makeMergeOp() covOperation {
+	outdirflag = flag.String("o", "", "Output directory to write")
+	pcombineflag = flag.Bool("pcombine", false, "Combine profiles derived from distinct program executables")
+	m := &mstate{
+		mm: newMetaMerge(),
+	}
+	return m
+}
+
+// mstate encapsulates state and provides methods for implementing the
+// merge operation. This type implements the CovDataVisitor interface,
+// and is designed to be used in concert with the CovDataReader
+// utility, which abstracts away most of the grubby details of reading
+// coverage data files. Most of the heavy lifting for merging is done
+// using apis from 'metaMerge' (this is mainly a wrapper around that
+// functionality).
+type mstate struct {
+	mm *metaMerge
+}
+
+func (m *mstate) Usage(msg string) {
+	if len(msg) > 0 {
+		fmt.Fprintf(os.Stderr, "error: %s\n", msg)
+	}
+	fmt.Fprintf(os.Stderr, "usage: go tool covdata merge -i=<directories> -o=<dir>\n\n")
+	flag.PrintDefaults()
+	fmt.Fprintf(os.Stderr, "\nExamples:\n\n")
+	fmt.Fprintf(os.Stderr, "  go tool covdata merge -i=dir1,dir2,dir3 -o=outdir\n\n")
+	fmt.Fprintf(os.Stderr, "  \tmerges all files in dir1/dir2/dir3\n")
+	fmt.Fprintf(os.Stderr, "  \tinto output dir outdir\n")
+	Exit(2)
+}
+
+func (m *mstate) Setup() {
+	if *indirsflag == "" {
+		m.Usage("select input directories with '-i' option")
+	}
+	if *outdirflag == "" {
+		m.Usage("select output directory with '-o' option")
+	}
+}
+
+func (m *mstate) BeginPod(p pods.Pod) {
+	m.mm.beginPod()
+}
+
+func (m *mstate) EndPod(p pods.Pod) {
+	m.mm.endPod(*pcombineflag)
+}
+
+func (m *mstate) BeginCounterDataFile(cdf string, cdr *decodecounter.CounterDataReader, dirIdx int) {
+	dbgtrace(2, "visit counter data file %s dirIdx %d", cdf, dirIdx)
+	m.mm.beginCounterDataFile(cdr)
+}
+
+func (m *mstate) EndCounterDataFile(cdf string, cdr *decodecounter.CounterDataReader, dirIdx int) {
+}
+
+func (m *mstate) VisitFuncCounterData(data decodecounter.FuncPayload) {
+	m.mm.visitFuncCounterData(data)
+}
+
+func (m *mstate) EndCounters() {
+}
+
+func (m *mstate) VisitMetaDataFile(mdf string, mfr *decodemeta.CoverageMetaFileReader) {
+	m.mm.visitMetaDataFile(mdf, mfr)
+}
+
+func (m *mstate) BeginPackage(pd *decodemeta.CoverageMetaDataDecoder, pkgIdx uint32) {
+	dbgtrace(3, "VisitPackage(pk=%d path=%s)", pkgIdx, pd.PackagePath())
+	m.mm.visitPackage(pd, pkgIdx, *pcombineflag)
+}
+
+func (m *mstate) EndPackage(pd *decodemeta.CoverageMetaDataDecoder, pkgIdx uint32) {
+}
+
+func (m *mstate) VisitFunc(pkgIdx uint32, fnIdx uint32, fd *coverage.FuncDesc) {
+	m.mm.visitFunc(pkgIdx, fnIdx, fd, mergeMode, *pcombineflag)
+}
+
+func (m *mstate) Finish() {
+	if *pcombineflag {
+		finalHash := m.mm.emitMeta(*outdirflag, true)
+		m.mm.emitCounters(*outdirflag, finalHash)
+	}
+}