util/convert_comments.go - boringssl - Git at Google

 // Copyright (c) 2017, 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.

 package main

 import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"strings"
 )

 // convert_comments.go converts C-style block comments to C++-style line
 // comments. A block comment is converted if all of the following are true:
 //
 //   * The comment begins after the first blank line, to leave the license
 //     blocks alone.
 //
 //   * There are no characters between the '*/' and the end of the line.
 //
 //   * Either one of the following are true:
 //
 //     - The comment fits on one line.
 //
 //     - Each line the comment spans begins with N spaces, followed by '/*' for
 //       the initial line or ' *' for subsequent lines, where N is the same for
 //       each line.
 //
 // This tool is a heuristic. While it gets almost all cases correct, the final
 // output should still be looked over and fixed up as needed.

 // allSpaces returns true if |s| consists entirely of spaces.
 func allSpaces(s string) bool {
 	return strings.IndexFunc(s, func(r rune) bool { return r != ' ' }) == -1
 }

 // isContinuation returns true if |s| is a continuation line for a multi-line
 // comment indented to the specified column.
 func isContinuation(s string, column int) bool {
 	if len(s) < column+2 {
 		return false
 	}
 	if !allSpaces(s[:column]) {
 		return false
 	}
 	return s[column:column+2] == " *"
 }

 // indexFrom behaves like strings.Index but only reports matches starting at
 // |idx|.
 func indexFrom(s, sep string, idx int) int {
 	ret := strings.Index(s[idx:], sep)
 	if ret < 0 {
 		return -1
 	}
 	return idx + ret
 }

 // A lineGroup is a contiguous group of lines with an eligible comment at the
 // same column. Any trailing '*/'s will already be removed.
 type lineGroup struct {
 	// column is the column where the eligible comment begins. line[column]
 	// and line[column+1] will both be replaced with '/'. It is -1 if this
 	// group is not to be converted.
 	column int
 	lines  []string
 }

 func addLine(groups *[]lineGroup, line string, column int) {
 	if len(*groups) == 0 || (*groups)[len(*groups)-1].column != column {
 		*groups = append(*groups, lineGroup{column, nil})
 	}
 	(*groups)[len(*groups)-1].lines = append((*groups)[len(*groups)-1].lines, line)
 }

 // writeLine writes |line| to |out|, followed by a newline.
 func writeLine(out *bytes.Buffer, line string) {
 	out.WriteString(line)
 	out.WriteByte('\n')
 }

 func convertComments(path string, in []byte) []byte {
 	lines := strings.Split(string(in), "\n")

 	// Account for the trailing newline.
 	if len(lines) > 0 && len(lines[len(lines)-1]) == 0 {
 		lines = lines[:len(lines)-1]
 	}

 	// First pass: identify all comments to be converted. Group them into
 	// lineGroups with the same column.
 	var groups []lineGroup

 	// Find the license block separator.
 	for len(lines) > 0 {
 		line := lines[0]
 		lines = lines[1:]
 		addLine(&groups, line, -1)
 		if len(line) == 0 {
 			break
 		}
 	}

 	// inComment is true if we are in the middle of a comment.
 	var inComment bool
 	// comment is the currently buffered multi-line comment to convert. If
 	// |inComment| is true and it is nil, the current multi-line comment is
 	// not convertable and we copy lines to |out| as-is.
 	var comment []string
 	// column is the column offset of |comment|.
 	var column int
 	for len(lines) > 0 {
 		line := lines[0]
 		lines = lines[1:]

 		var idx int
 		if inComment {
 			// Stop buffering if this comment isn't eligible.
 			if comment != nil && !isContinuation(line, column) {
 				for _, l := range comment {
 					addLine(&groups, l, -1)
 				}
 				comment = nil
 			}

 			// Look for the end of the current comment.
 			idx = strings.Index(line, "*/")
 			if idx < 0 {
 				if comment != nil {
 					comment = append(comment, line)
 				} else {
 					addLine(&groups, line, -1)
 				}
 				continue
 			}

 			inComment = false
 			if comment != nil {
 				if idx == len(line)-2 {
 					// This is a convertable multi-line comment.
 					if idx >= column+2 {
 						// |idx| may be equal to
 						// |column| + 1, if the line is
 						// a '*/' on its own. In that
 						// case, we discard the line.
 						comment = append(comment, line[:idx])
 					}
 					for _, l := range comment {
 						addLine(&groups, l, column)
 					}
 					comment = nil
 					continue
 				}

 				// Flush the buffered comment unmodified.
 				for _, l := range comment {
 					addLine(&groups, l, -1)
 				}
 				comment = nil
 			}
 			idx += 2
 		}

 		// Parse starting from |idx|, looking for either a convertable
 		// line comment or a multi-line comment.
 		for {
 			idx = indexFrom(line, "/*", idx)
 			if idx < 0 {
 				addLine(&groups, line, -1)
 				break
 			}

 			endIdx := indexFrom(line, "*/", idx)
 			if endIdx < 0 {
 				// The comment is, so far, eligible for conversion.
 				inComment = true
 				column = idx
 				comment = []string{line}
 				break
 			}

 			if endIdx != len(line)-2 {
 				// Continue parsing for more comments in this line.
 				idx = endIdx + 2
 				continue
 			}

 			addLine(&groups, line[:endIdx], idx)
 			break
 		}
 	}

 	// Second pass: convert the lineGroups, adjusting spacing as needed.
 	var out bytes.Buffer
 	var lineNo int
 	for _, group := range groups {
 		if group.column < 0 {
 			for _, line := range group.lines {
 				writeLine(&out, line)
 			}
 		} else {
 			// Google C++ style prefers two spaces before a comment
 			// if it is on the same line as code, but clang-format
 			// has been placing one space for block comments. All
 			// comments within a group should be adjusted by the
 			// same amount.
 			var adjust string
 			for _, line := range group.lines {
 				if !allSpaces(line[:group.column]) && line[group.column-1] != '(' {
 					if line[group.column-1] != ' ' {
 						if len(adjust) < 2 {
 							adjust = "  "
 						}
 					} else if line[group.column-2] != ' ' {
 						if len(adjust) < 1 {
 							adjust = " "
 						}
 					}
 				}
 			}

 			for i, line := range group.lines {
 				newLine := fmt.Sprintf("%s%s//%s", line[:group.column], adjust, strings.TrimRight(line[group.column+2:], " "))
 				if len(newLine) > 80 {
 					fmt.Fprintf(os.Stderr, "%s:%d: Line is now longer than 80 characters\n", path, lineNo+i+1)
 				}
 				writeLine(&out, newLine)
 			}

 		}
 		lineNo += len(group.lines)
 	}
 	return out.Bytes()
 }

 func main() {
 	for _, arg := range os.Args[1:] {
 		in, err := ioutil.ReadFile(arg)
 		if err != nil {
 			panic(err)
 		}
 		if err := ioutil.WriteFile(arg, convertComments(arg, in), 0666); err != nil {
 			panic(err)
 		}
 	}
 }
	// Copyright (c) 2017, 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.

	package main

	import (
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"strings"
	)

	// convert_comments.go converts C-style block comments to C++-style line
	// comments. A block comment is converted if all of the following are true:
	//
	// * The comment begins after the first blank line, to leave the license
	// blocks alone.
	//
	// * There are no characters between the '*/' and the end of the line.
	//
	// * Either one of the following are true:
	//
	// - The comment fits on one line.
	//
	// - Each line the comment spans begins with N spaces, followed by '/*' for
	// the initial line or ' *' for subsequent lines, where N is the same for
	// each line.
	//
	// This tool is a heuristic. While it gets almost all cases correct, the final
	// output should still be looked over and fixed up as needed.

	// allSpaces returns true if \|s\| consists entirely of spaces.
	func allSpaces(s string) bool {
	return strings.IndexFunc(s, func(r rune) bool { return r != ' ' }) == -1
	}

	// isContinuation returns true if \|s\| is a continuation line for a multi-line
	// comment indented to the specified column.
	func isContinuation(s string, column int) bool {
	if len(s) < column+2 {
	return false
	}
	if !allSpaces(s[:column]) {
	return false
	}
	return s[column:column+2] == " *"
	}

	// indexFrom behaves like strings.Index but only reports matches starting at
	// \|idx\|.
	func indexFrom(s, sep string, idx int) int {
	ret := strings.Index(s[idx:], sep)
	if ret < 0 {
	return -1
	}
	return idx + ret
	}

	// A lineGroup is a contiguous group of lines with an eligible comment at the
	// same column. Any trailing '*/'s will already be removed.
	type lineGroup struct {
	// column is the column where the eligible comment begins. line[column]
	// and line[column+1] will both be replaced with '/'. It is -1 if this
	// group is not to be converted.
	column int
	lines []string
	}

	func addLine(groups *[]lineGroup, line string, column int) {
	if len(groups) == 0 \|\| (groups)[len(*groups)-1].column != column {
	groups = append(groups, lineGroup{column, nil})
	}
	(groups)[len(groups)-1].lines = append((groups)[len(groups)-1].lines, line)
	}

	// writeLine writes \|line\| to \|out\|, followed by a newline.
	func writeLine(out *bytes.Buffer, line string) {
	out.WriteString(line)
	out.WriteByte('\n')
	}

	func convertComments(path string, in []byte) []byte {
	lines := strings.Split(string(in), "\n")

	// Account for the trailing newline.
	if len(lines) > 0 && len(lines[len(lines)-1]) == 0 {
	lines = lines[:len(lines)-1]
	}

	// First pass: identify all comments to be converted. Group them into
	// lineGroups with the same column.
	var groups []lineGroup

	// Find the license block separator.
	for len(lines) > 0 {
	line := lines[0]
	lines = lines[1:]
	addLine(&groups, line, -1)
	if len(line) == 0 {
	break
	}
	}

	// inComment is true if we are in the middle of a comment.
	var inComment bool
	// comment is the currently buffered multi-line comment to convert. If
	// \|inComment\| is true and it is nil, the current multi-line comment is
	// not convertable and we copy lines to \|out\| as-is.
	var comment []string
	// column is the column offset of \|comment\|.
	var column int
	for len(lines) > 0 {
	line := lines[0]
	lines = lines[1:]

	var idx int
	if inComment {
	// Stop buffering if this comment isn't eligible.
	if comment != nil && !isContinuation(line, column) {
	for _, l := range comment {
	addLine(&groups, l, -1)
	}
	comment = nil
	}

	// Look for the end of the current comment.
	idx = strings.Index(line, "*/")
	if idx < 0 {
	if comment != nil {
	comment = append(comment, line)
	} else {
	addLine(&groups, line, -1)
	}
	continue
	}

	inComment = false
	if comment != nil {
	if idx == len(line)-2 {
	// This is a convertable multi-line comment.
	if idx >= column+2 {
	// \|idx\| may be equal to
	// \|column\| + 1, if the line is
	// a '*/' on its own. In that
	// case, we discard the line.
	comment = append(comment, line[:idx])
	}
	for _, l := range comment {
	addLine(&groups, l, column)
	}
	comment = nil
	continue
	}

	// Flush the buffered comment unmodified.
	for _, l := range comment {
	addLine(&groups, l, -1)
	}
	comment = nil
	}
	idx += 2
	}

	// Parse starting from \|idx\|, looking for either a convertable
	// line comment or a multi-line comment.
	for {
	idx = indexFrom(line, "/*", idx)
	if idx < 0 {
	addLine(&groups, line, -1)
	break
	}

	endIdx := indexFrom(line, "*/", idx)
	if endIdx < 0 {
	// The comment is, so far, eligible for conversion.
	inComment = true
	column = idx
	comment = []string{line}
	break
	}

	if endIdx != len(line)-2 {
	// Continue parsing for more comments in this line.
	idx = endIdx + 2
	continue
	}

	addLine(&groups, line[:endIdx], idx)
	break
	}
	}

	// Second pass: convert the lineGroups, adjusting spacing as needed.
	var out bytes.Buffer
	var lineNo int
	for _, group := range groups {
	if group.column < 0 {
	for _, line := range group.lines {
	writeLine(&out, line)
	}
	} else {
	// Google C++ style prefers two spaces before a comment
	// if it is on the same line as code, but clang-format
	// has been placing one space for block comments. All
	// comments within a group should be adjusted by the
	// same amount.
	var adjust string
	for _, line := range group.lines {
	if !allSpaces(line[:group.column]) && line[group.column-1] != '(' {
	if line[group.column-1] != ' ' {
	if len(adjust) < 2 {
	adjust = " "
	}
	} else if line[group.column-2] != ' ' {
	if len(adjust) < 1 {
	adjust = " "
	}
	}
	}
	}

	for i, line := range group.lines {
	newLine := fmt.Sprintf("%s%s//%s", line[:group.column], adjust, strings.TrimRight(line[group.column+2:], " "))
	if len(newLine) > 80 {
	fmt.Fprintf(os.Stderr, "%s:%d: Line is now longer than 80 characters\n", path, lineNo+i+1)
	}
	writeLine(&out, newLine)
	}

	}
	lineNo += len(group.lines)
	}
	return out.Bytes()
	}

	func main() {
	for _, arg := range os.Args[1:] {
	in, err := ioutil.ReadFile(arg)
	if err != nil {
	panic(err)
	}
	if err := ioutil.WriteFile(arg, convertComments(arg, in), 0666); err != nil {
	panic(err)
	}
	}
	}