Use scan instead of copy in parallel mode (#13)

.github/workflows/golangci-lint.yml

@@ -21,13 +21,13 @@ jobs:
     steps:
       - uses: actions/setup-go@v3
         with:
-          go-version: 1.21.x
+          go-version: 1.22.x
       - uses: actions/checkout@v2
       - name: golangci-lint
-        uses: golangci/golangci-lint-action@v3.7.0
+        uses: golangci/golangci-lint-action@v4.0.0
         with:
           # Required: the version of golangci-lint is required and must be specified without patch version: we always use the latest patch version.
-          version: v1.55.2
+          version: v1.56.2
 
           # Optional: working directory, useful for monorepos
           # working-directory: somedir

.github/workflows/gorelease.yml

@@ -9,7 +9,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  GO_VERSION: 1.21.x
+  GO_VERSION: 1.22.x
 jobs:
   gorelease:
     runs-on: ubuntu-latest

.github/workflows/release-assets.yml

@@ -8,13 +8,13 @@ on:
       - created
 env:
   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-  GO_VERSION: '1.22.0-rc.1'
+  GO_VERSION: 1.22.x
   LINUX_AMD64_BUILD_OPTIONS: '-tags cgo_zstd'
   GOAMD64: v3
 jobs:
   build:
     name: Upload Release Assets
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - name: Install Go stable
         if: env.GO_VERSION != 'tip'

.github/workflows/test-unit.yml

@@ -15,13 +15,13 @@ concurrency:
 env:
   GO111MODULE: "on"
   RUN_BASE_COVERAGE: "on"  # Runs test for PR base in case base test coverage is missing.
-  COV_GO_VERSION: 1.21.x   # Version of Go to collect coverage
+  COV_GO_VERSION: 1.22.x   # Version of Go to collect coverage
   TARGET_DELTA_COV: 90     # Target coverage of changed lines, in percents
 jobs:
   test:
     strategy:
       matrix:
-        go-version: [ 1.19.x, 1.20.x, 1.21.x ]
+        go-version: [ 1.20.x, 1.21.x, 1.22.x ]
     runs-on: ubuntu-latest
     steps:
       - name: Install Go stable

.golangci.yml

@@ -19,7 +19,7 @@ linters-settings:
   funlen:
     lines: 80
   cyclop:
-    max-complexity: 15
+    max-complexity: 16
 
 linters:
   enable-all: true

Makefile

@@ -1,4 +1,4 @@
-#GOLANGCI_LINT_VERSION := "v1.55.2" # Optional configuration to pinpoint golangci-lint version.
+#GOLANGCI_LINT_VERSION := "v1.56.2" # Optional configuration to pinpoint golangci-lint version.
 
 # The head of Makefile determines location of dev-go to include standard targets.
 GO ?= go

cmd/catp/catp/app.go

@@ -279,7 +279,7 @@ func (r *runner) cat(filename string) (err error) {
 		})
 	}
 
-	if len(r.pass) > 0 || len(r.skip) > 0 {
+	if len(r.pass) > 0 || len(r.skip) > 0 || r.parallel > 1 {
 		r.scanFile(rd, out)
 	} else {
 		r.readFile(rd, out)
@@ -364,6 +364,8 @@ func Main() error { //nolint:funlen,cyclop,gocognit,gocyclo
 		skip stringFlags
 	)
 
+	r := &runner{}
+
 	flag.Var(&pass, "pass", "filter matching, may contain multiple AND patterns separated by ^,\n"+
 		"if filter matches, line is passed to the output (unless filtered out by -skip)\n"+
 		"each -pass value is added with OR logic,\n"+
@@ -374,20 +376,21 @@ func Main() error { //nolint:funlen,cyclop,gocognit,gocyclo
 		"each -skip value is added with OR logic,\n"+
 		"for example, you can use \"-skip quux^baz -skip fooO\" to skip lines that have (quux AND baz) OR fooO")
 
-	parallel := flag.Int("parallel", 1, "number of parallel readers if multiple files are provided\n"+
+	flag.IntVar(&r.parallel, "parallel", 1, "number of parallel readers if multiple files are provided\n"+
 		"lines from different files will go to output simultaneously (out of order of files, but in order of lines in each file)\n"+
 		"use 0 for multi-threaded zst decoder (slightly faster at cost of more CPU)")
 
 	cpuProfile := flag.String("dbg-cpu-prof", "", "write first 10 seconds of CPU profile to file")
 	memProfile := flag.String("dbg-mem-prof", "", "write heap profile to file after 10 seconds")
 	output := flag.String("output", "", "output to file instead of STDOUT")
-	outDir := flag.String("out-dir", "", "output to directory instead of STDOUT\n"+
-		"files will be written to out dir with original base names\n"+
-		"disables output flag")
 	noProgress := flag.Bool("no-progress", false, "disable progress printing")
 	progressJSON := flag.String("progress-json", "", "write current progress to a file")
 	ver := flag.Bool("version", false, "print version and exit")
 
+	flag.StringVar(&r.outDir, "out-dir", "", "output to directory instead of STDOUT\n"+
+		"files will be written to out dir with original base names\n"+
+		"disables output flag")
+
 	flag.Usage = func() {
 		fmt.Println("catp", version.Module("github.com/bool64/progress").Version+",",
 			version.Info().GoVersion, strings.Join(versionExtra, " "))
@@ -420,12 +423,7 @@ func Main() error { //nolint:funlen,cyclop,gocognit,gocyclo
 		defer pprof.StopCPUProfile()
 	}
 
-	r := &runner{}
-
-	r.parallel = *parallel
-	r.outDir = *outDir
-
-	if *output != "" && *outDir == "" { //nolint:nestif
+	if *output != "" && r.outDir == "" { //nolint:nestif
 		out, err := os.Create(*output)
 		if err != nil {
 			return fmt.Errorf("failed to create output file %s: %w", *output, err)
@@ -503,7 +501,7 @@ func Main() error { //nolint:funlen,cyclop,gocognit,gocyclo
 		r.sizes[fn] = st.Size()
 	}
 
-	if *parallel >= 2 {
+	if r.parallel >= 2 {
 		pr := r.pr
 		pr.Start(func(t *progress.Task) {
 			t.TotalBytes = func() int64 { return r.totalBytes }
@@ -513,7 +511,7 @@ func Main() error { //nolint:funlen,cyclop,gocognit,gocyclo
 			t.PrintOnStart = true
 		})
 
-		sem := make(chan struct{}, *parallel)
+		sem := make(chan struct{}, r.parallel)
 		errs := make(chan error, 1)
 
 		for i := 0; i < flag.NArg(); i++ {

go.mod

@@ -4,7 +4,7 @@ go 1.21
 
 require (
 	github.com/DataDog/zstd v1.5.5
-	github.com/bool64/dev v0.2.33
-	github.com/klauspost/compress v1.17.4
+	github.com/bool64/dev v0.2.34
+	github.com/klauspost/compress v1.17.8
 	github.com/klauspost/pgzip v1.2.6
 )

go.sum

@@ -2,7 +2,11 @@ github.com/DataDog/zstd v1.5.5 h1:oWf5W7GtOLgp6bciQYDmhHHjdhYkALu6S/5Ni9ZgSvQ=
 github.com/DataDog/zstd v1.5.5/go.mod h1:g4AWEaM3yOg3HYfnJ3YIawPnVdXJh9QME85blwSAmyw=
 github.com/bool64/dev v0.2.33 h1:ETAcSa8H9w4talcCdSQCCnLX7PMHmuxdLcDl6TpSDj4=
 github.com/bool64/dev v0.2.33/go.mod h1:iJbh1y/HkunEPhgebWRNcs8wfGq7sjvJ6W5iabL8ACg=
+github.com/bool64/dev v0.2.34 h1:P9n315P8LdpxusnYQ0X7MP1CZXwBK5ae5RZrd+GdSZE=
+github.com/bool64/dev v0.2.34/go.mod h1:iJbh1y/HkunEPhgebWRNcs8wfGq7sjvJ6W5iabL8ACg=
 github.com/klauspost/compress v1.17.4 h1:Ej5ixsIri7BrIjBkRZLTo6ghwrEtHFk7ijlczPW4fZ4=
 github.com/klauspost/compress v1.17.4/go.mod h1:/dCuZOvVtNoHsyb+cuJD3itjs3NbnF6KH9zAO4BDxPM=
+github.com/klauspost/compress v1.17.8 h1:YcnTYrq7MikUT7k0Yb5eceMmALQPYBW/Xltxn0NAMnU=
+github.com/klauspost/compress v1.17.8/go.mod h1:Di0epgTjJY877eYKx5yC51cX2A2Vl2ibi7bDH9ttBbw=
 github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
 github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=