1 files changed, 115 insertions, 0 deletions
diff --git a/src/cmd/go/internal/fmtcmd/fmt.go b/src/cmd/go/internal/fmtcmd/fmt.go
new file mode 100644
index 0000000..62b22f6
--- /dev/null
+++ b/src/cmd/go/internal/fmtcmd/fmt.go
@@ -0,0 +1,115 @@
+// Copyright 2011 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 fmtcmd implements the “go fmt” command.
+package fmtcmd
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"cmd/go/internal/base"
+	"cmd/go/internal/cfg"
+	"cmd/go/internal/load"
+	"cmd/go/internal/modload"
+	"cmd/internal/sys"
+)
+
+func init() {
+	base.AddBuildFlagsNX(&CmdFmt.Flag)
+	base.AddChdirFlag(&CmdFmt.Flag)
+	base.AddModFlag(&CmdFmt.Flag)
+	base.AddModCommonFlags(&CmdFmt.Flag)
+}
+
+var CmdFmt = &base.Command{
+	Run:       runFmt,
+	UsageLine: "go fmt [-n] [-x] [packages]",
+	Short:     "gofmt (reformat) package sources",
+	Long: `
+Fmt runs the command 'gofmt -l -w' on the packages named
+by the import paths. It prints the names of the files that are modified.
+
+For more about gofmt, see 'go doc cmd/gofmt'.
+For more about specifying packages, see 'go help packages'.
+
+The -n flag prints commands that would be executed.
+The -x flag prints commands as they are executed.
+
+The -mod flag's value sets which module download mode
+to use: readonly or vendor. See 'go help modules' for more.
+
+To run gofmt with specific options, run gofmt itself.
+
+See also: go fix, go vet.
+	`,
+}
+
+func runFmt(ctx context.Context, cmd *base.Command, args []string) {
+	printed := false
+	gofmt := gofmtPath()
+
+	gofmtArgs := []string{gofmt, "-l", "-w"}
+	gofmtArgLen := len(gofmt) + len(" -l -w")
+
+	baseGofmtArgs := len(gofmtArgs)
+	baseGofmtArgLen := gofmtArgLen
+
+	for _, pkg := range load.PackagesAndErrors(ctx, load.PackageOpts{}, args) {
+		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
+			if !printed {
+				fmt.Fprintf(os.Stderr, "go: not formatting packages in dependency modules\n")
+				printed = true
+			}
+			continue
+		}
+		if pkg.Error != nil {
+			var nogo *load.NoGoError
+			var embed *load.EmbedError
+			if (errors.As(pkg.Error, &nogo) || errors.As(pkg.Error, &embed)) && len(pkg.InternalAllGoFiles()) > 0 {
+				// Skip this error, as we will format
+				// all files regardless.
+			} else {
+				base.Errorf("%v", pkg.Error)
+				continue
+			}
+		}
+		// Use pkg.gofiles instead of pkg.Dir so that
+		// the command only applies to this package,
+		// not to packages in subdirectories.
+		files := base.RelPaths(pkg.InternalAllGoFiles())
+		for _, file := range files {
+			gofmtArgs = append(gofmtArgs, file)
+			gofmtArgLen += 1 + len(file) // plus separator
+			if gofmtArgLen >= sys.ExecArgLengthLimit {
+				base.Run(gofmtArgs)
+				gofmtArgs = gofmtArgs[:baseGofmtArgs]
+				gofmtArgLen = baseGofmtArgLen
+			}
+		}
+	}
+	if len(gofmtArgs) > baseGofmtArgs {
+		base.Run(gofmtArgs)
+	}
+}
+
+func gofmtPath() string {
+	gofmt := "gofmt" + cfg.ToolExeSuffix()
+
+	gofmtPath := filepath.Join(cfg.GOBIN, gofmt)
+	if _, err := os.Stat(gofmtPath); err == nil {
+		return gofmtPath
+	}
+
+	gofmtPath = filepath.Join(cfg.GOROOT, "bin", gofmt)
+	if _, err := os.Stat(gofmtPath); err == nil {
+		return gofmtPath
+	}
+
+	// fallback to looking for gofmt in $PATH
+	return "gofmt"
+}