1 files changed, 203 insertions, 0 deletions
diff --git a/src/util/godeps.go b/src/util/godeps.go
new file mode 100644
index 00000000..960faa46
--- /dev/null
+++ b/src/util/godeps.go
@@ -0,0 +1,203 @@
+// Copyright (c) 2018, Google Inc.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+// godeps prints out dependencies of a package in either CMake or Make depfile
+// format, for incremental rebuilds.
+//
+// The depfile format is preferred. It works correctly when new files are added.
+// However, CMake only supports depfiles for custom commands with Ninja and
+// starting CMake 3.7. For other configurations, we also support CMake's format,
+// but CMake must be rerun when file lists change.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"go/build"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+var (
+	format  = flag.String("format", "cmake", "The format to output to, either 'cmake' or 'depfile'")
+	mainPkg = flag.String("pkg", "", "The package to print dependencies for")
+	target  = flag.String("target", "", "The name of the output file")
+	out     = flag.String("out", "", "The path to write the output to. If unset, this is stdout")
+)
+
+func cMakeQuote(in string) string {
+	// See https://cmake.org/cmake/help/v3.0/manual/cmake-language.7.html#quoted-argument
+	var b strings.Builder
+	b.Grow(len(in))
+	// Iterate over in as bytes.
+	for i := 0; i < len(in); i++ {
+		switch c := in[i]; c {
+		case '\\', '"':
+			b.WriteByte('\\')
+			b.WriteByte(c)
+		case '\t':
+			b.WriteString("\\t")
+		case '\r':
+			b.WriteString("\\r")
+		case '\n':
+			b.WriteString("\\n")
+		default:
+			b.WriteByte(in[i])
+		}
+	}
+	return b.String()
+}
+
+func writeCMake(outFile *os.File, files []string) error {
+	for i, file := range files {
+		if i != 0 {
+			if _, err := outFile.WriteString(";"); err != nil {
+				return err
+			}
+		}
+		if _, err := outFile.WriteString(cMakeQuote(file)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func makeQuote(in string) string {
+	// See https://www.gnu.org/software/make/manual/make.html#Rule-Syntax
+	var b strings.Builder
+	b.Grow(len(in))
+	// Iterate over in as bytes.
+	for i := 0; i < len(in); i++ {
+		switch c := in[i]; c {
+		case '$':
+			b.WriteString("$$")
+		case '#', '\\', ' ':
+			b.WriteByte('\\')
+			b.WriteByte(c)
+		default:
+			b.WriteByte(c)
+		}
+	}
+	return b.String()
+}
+
+func writeDepfile(outFile *os.File, files []string) error {
+	if _, err := fmt.Fprintf(outFile, "%s:", makeQuote(*target)); err != nil {
+		return err
+	}
+	for _, file := range files {
+		if _, err := fmt.Fprintf(outFile, " %s", makeQuote(file)); err != nil {
+			return err
+		}
+	}
+	_, err := outFile.WriteString("\n")
+	return err
+}
+
+func appendPrefixed(list, newFiles []string, prefix string) []string {
+	for _, file := range newFiles {
+		list = append(list, filepath.Join(prefix, file))
+	}
+	return list
+}
+
+func main() {
+	flag.Parse()
+
+	if len(*mainPkg) == 0 {
+		fmt.Fprintf(os.Stderr, "-pkg argument is required.\n")
+		os.Exit(1)
+	}
+
+	var isDepfile bool
+	switch *format {
+	case "depfile":
+		isDepfile = true
+	case "cmake":
+		isDepfile = false
+	default:
+		fmt.Fprintf(os.Stderr, "Unknown format: %q\n", *format)
+		os.Exit(1)
+	}
+
+	if isDepfile && len(*target) == 0 {
+		fmt.Fprintf(os.Stderr, "-target argument is required for depfile.\n")
+		os.Exit(1)
+	}
+
+	done := make(map[string]struct{})
+	var files []string
+	var recurse func(pkgName string) error
+	recurse = func(pkgName string) error {
+		pkg, err := build.Default.Import(pkgName, ".", 0)
+		if err != nil {
+			return err
+		}
+
+		// Skip standard packages.
+		if pkg.Goroot {
+			return nil
+		}
+
+		// Skip already-visited packages.
+		if _, ok := done[pkg.Dir]; ok {
+			return nil
+		}
+		done[pkg.Dir] = struct{}{}
+
+		files = appendPrefixed(files, pkg.GoFiles, pkg.Dir)
+		files = appendPrefixed(files, pkg.CgoFiles, pkg.Dir)
+		// Include ignored Go files. A subsequent change may cause them
+		// to no longer be ignored.
+		files = appendPrefixed(files, pkg.IgnoredGoFiles, pkg.Dir)
+
+		// Recurse into imports.
+		for _, importName := range pkg.Imports {
+			if err := recurse(importName); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+	if err := recurse(*mainPkg); err != nil {
+		fmt.Fprintf(os.Stderr, "Error getting dependencies: %s\n", err)
+		os.Exit(1)
+	}
+
+	sort.Strings(files)
+
+	outFile := os.Stdout
+	if len(*out) != 0 {
+		var err error
+		outFile, err = os.Create(*out)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error writing output: %s\n", err)
+			os.Exit(1)
+		}
+		defer outFile.Close()
+	}
+
+	var err error
+	if isDepfile {
+		err = writeDepfile(outFile, files)
+	} else {
+		err = writeCMake(outFile, files)
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error writing output: %s\n", err)
+		os.Exit(1)
+	}
+}