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/*
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.googlejavaformat.java.javadoc;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Verify.verify;
import static com.google.common.collect.Iterators.peekingIterator;
import static com.google.googlejavaformat.java.javadoc.Token.Type.BEGIN_JAVADOC;
import static com.google.googlejavaformat.java.javadoc.Token.Type.BLOCKQUOTE_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.BLOCKQUOTE_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.BR_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.CODE_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.CODE_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.END_JAVADOC;
import static com.google.googlejavaformat.java.javadoc.Token.Type.FOOTER_JAVADOC_TAG_START;
import static com.google.googlejavaformat.java.javadoc.Token.Type.FORCED_NEWLINE;
import static com.google.googlejavaformat.java.javadoc.Token.Type.HEADER_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.HEADER_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.HTML_COMMENT;
import static com.google.googlejavaformat.java.javadoc.Token.Type.LIST_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.LIST_ITEM_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.LIST_ITEM_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.LIST_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.LITERAL;
import static com.google.googlejavaformat.java.javadoc.Token.Type.MOE_BEGIN_STRIP_COMMENT;
import static com.google.googlejavaformat.java.javadoc.Token.Type.MOE_END_STRIP_COMMENT;
import static com.google.googlejavaformat.java.javadoc.Token.Type.OPTIONAL_LINE_BREAK;
import static com.google.googlejavaformat.java.javadoc.Token.Type.PARAGRAPH_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.PARAGRAPH_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.PRE_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.PRE_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.TABLE_CLOSE_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.TABLE_OPEN_TAG;
import static com.google.googlejavaformat.java.javadoc.Token.Type.WHITESPACE;
import static java.lang.String.format;
import static java.util.regex.Pattern.CASE_INSENSITIVE;
import static java.util.regex.Pattern.DOTALL;
import static java.util.regex.Pattern.compile;
import com.google.common.base.CharMatcher;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.PeekingIterator;
import com.google.googlejavaformat.java.javadoc.Token.Type;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;
import java.util.regex.Pattern;
/** Lexer for the Javadoc formatter. */
final class JavadocLexer {
/** Takes a Javadoc comment, including ∕✱✱ and ✱∕, and returns tokens, including ∕✱✱ and ✱∕. */
static ImmutableList lex(String input) throws LexException {
/*
* TODO(cpovirk): In theory, we should interpret Unicode escapes (yet output them in their
* original form). This would mean mean everything from an encoded ∕✱✱ to an encoded tag,
* so we'll probably never bother.
*/
input = stripJavadocBeginAndEnd(input);
input = normalizeLineEndings(input);
return new JavadocLexer(new CharStream(input)).generateTokens();
}
/** The lexer crashes on windows line endings, so for now just normalize to `\n`. */
// TODO(cushon): use the platform line separator for output
private static String normalizeLineEndings(String input) {
return NON_UNIX_LINE_ENDING.matcher(input).replaceAll("\n");
}
private static final Pattern NON_UNIX_LINE_ENDING = Pattern.compile("\r\n?");
private static String stripJavadocBeginAndEnd(String input) {
/*
* We do this ahead of time so that the main part of the lexer need not say things like
* "(?![*]/)" to avoid accidentally swallowing ✱∕ when consuming a newline.
*/
checkArgument(input.startsWith("/**"), "Missing /**: %s", input);
checkArgument(input.endsWith("*/") && input.length() > 4, "Missing */: %s", input);
return input.substring("/**".length(), input.length() - "*/".length());
}
private final CharStream input;
private final NestingCounter braceDepth = new NestingCounter();
private final NestingCounter preDepth = new NestingCounter();
private final NestingCounter codeDepth = new NestingCounter();
private final NestingCounter tableDepth = new NestingCounter();
private boolean somethingSinceNewline;
private JavadocLexer(CharStream input) {
this.input = checkNotNull(input);
}
private ImmutableList generateTokens() throws LexException {
ImmutableList.Builder tokens = ImmutableList.builder();
Token token = new Token(BEGIN_JAVADOC, "/**");
tokens.add(token);
while (!input.isExhausted()) {
token = readToken();
tokens.add(token);
}
checkMatchingTags();
token = new Token(END_JAVADOC, "*/");
tokens.add(token);
ImmutableList result = tokens.build();
result = joinAdjacentLiteralsAndAdjacentWhitespace(result);
result = inferParagraphTags(result);
result = optionalizeSpacesAfterLinks(result);
result = deindentPreCodeBlocks(result);
return result;
}
private Token readToken() throws LexException {
Type type = consumeToken();
String value = input.readAndResetRecorded();
return new Token(type, value);
}
private Type consumeToken() throws LexException {
boolean preserveExistingFormatting = preserveExistingFormatting();
if (input.tryConsumeRegex(NEWLINE_PATTERN)) {
somethingSinceNewline = false;
return preserveExistingFormatting ? FORCED_NEWLINE : WHITESPACE;
} else if (input.tryConsume(" ") || input.tryConsume("\t")) {
// TODO(cpovirk): How about weird whitespace chars? Ideally we'd distinguish breaking vs. not.
// Returning LITERAL here prevent us from breaking a line. For more info, see LITERAL.
return preserveExistingFormatting ? LITERAL : WHITESPACE;
}
/*
* TODO(cpovirk): Maybe try to detect things like "{@code\n@GwtCompatible}" that aren't intended
* as tags. But in the most likely case, in which that happens inside {@code, we have no
* great options for fixing it.
* https://github.com/google/google-java-format/issues/7#issuecomment-197383926
*/
if (!somethingSinceNewline && input.tryConsumeRegex(FOOTER_TAG_PATTERN)) {
checkMatchingTags();
somethingSinceNewline = true;
return FOOTER_JAVADOC_TAG_START;
}
somethingSinceNewline = true;
if (input.tryConsumeRegex(INLINE_TAG_OPEN_PATTERN)) {
braceDepth.increment();
return LITERAL;
} else if (input.tryConsume("{")) {
braceDepth.incrementIfPositive();
return LITERAL;
} else if (input.tryConsume("}")) {
braceDepth.decrementIfPositive();
return LITERAL;
}
// Inside an inline tag, don't do any HTML interpretation.
if (braceDepth.isPositive()) {
verify(input.tryConsumeRegex(LITERAL_PATTERN));
return LITERAL;
}
if (input.tryConsumeRegex(PRE_OPEN_PATTERN)) {
preDepth.increment();
return preserveExistingFormatting ? LITERAL : PRE_OPEN_TAG;
} else if (input.tryConsumeRegex(PRE_CLOSE_PATTERN)) {
preDepth.decrementIfPositive();
return preserveExistingFormatting() ? LITERAL : PRE_CLOSE_TAG;
}
if (input.tryConsumeRegex(CODE_OPEN_PATTERN)) {
codeDepth.increment();
return preserveExistingFormatting ? LITERAL : CODE_OPEN_TAG;
} else if (input.tryConsumeRegex(CODE_CLOSE_PATTERN)) {
codeDepth.decrementIfPositive();
return preserveExistingFormatting() ? LITERAL : CODE_CLOSE_TAG;
}
if (input.tryConsumeRegex(TABLE_OPEN_PATTERN)) {
tableDepth.increment();
return preserveExistingFormatting ? LITERAL : TABLE_OPEN_TAG;
} else if (input.tryConsumeRegex(TABLE_CLOSE_PATTERN)) {
tableDepth.decrementIfPositive();
return preserveExistingFormatting() ? LITERAL : TABLE_CLOSE_TAG;
}
if (preserveExistingFormatting) {
verify(input.tryConsumeRegex(LITERAL_PATTERN));
return LITERAL;
}
if (input.tryConsumeRegex(PARAGRAPH_OPEN_PATTERN)) {
return PARAGRAPH_OPEN_TAG;
} else if (input.tryConsumeRegex(PARAGRAPH_CLOSE_PATTERN)) {
return PARAGRAPH_CLOSE_TAG;
} else if (input.tryConsumeRegex(LIST_OPEN_PATTERN)) {
return LIST_OPEN_TAG;
} else if (input.tryConsumeRegex(LIST_CLOSE_PATTERN)) {
return LIST_CLOSE_TAG;
} else if (input.tryConsumeRegex(LIST_ITEM_OPEN_PATTERN)) {
return LIST_ITEM_OPEN_TAG;
} else if (input.tryConsumeRegex(LIST_ITEM_CLOSE_PATTERN)) {
return LIST_ITEM_CLOSE_TAG;
} else if (input.tryConsumeRegex(BLOCKQUOTE_OPEN_PATTERN)) {
return BLOCKQUOTE_OPEN_TAG;
} else if (input.tryConsumeRegex(BLOCKQUOTE_CLOSE_PATTERN)) {
return BLOCKQUOTE_CLOSE_TAG;
} else if (input.tryConsumeRegex(HEADER_OPEN_PATTERN)) {
return HEADER_OPEN_TAG;
} else if (input.tryConsumeRegex(HEADER_CLOSE_PATTERN)) {
return HEADER_CLOSE_TAG;
} else if (input.tryConsumeRegex(BR_PATTERN)) {
return BR_TAG;
} else if (input.tryConsumeRegex(MOE_BEGIN_STRIP_COMMENT_PATTERN)) {
return MOE_BEGIN_STRIP_COMMENT;
} else if (input.tryConsumeRegex(MOE_END_STRIP_COMMENT_PATTERN)) {
return MOE_END_STRIP_COMMENT;
} else if (input.tryConsumeRegex(HTML_COMMENT_PATTERN)) {
return HTML_COMMENT;
} else if (input.tryConsumeRegex(LITERAL_PATTERN)) {
return LITERAL;
}
throw new AssertionError();
}
private boolean preserveExistingFormatting() {
return preDepth.isPositive() || tableDepth.isPositive() || codeDepth.isPositive();
}
private void checkMatchingTags() throws LexException {
if (braceDepth.isPositive()
|| preDepth.isPositive()
|| tableDepth.isPositive()
|| codeDepth.isPositive()) {
throw new LexException();
}
}
/**
* Join together adjacent literal tokens, and join together adjacent whitespace tokens.
*
* For literal tokens, this means something like {@code ["", "foo", ""] =>
* ["foo"]}. See {@link #LITERAL_PATTERN} for discussion of why those tokens are separate
* to begin with.
*
*
Whitespace tokens are treated analogously. We don't really "want" to join whitespace tokens,
* but in the course of joining literals, we incidentally join whitespace, too. We do take
* advantage of the joining later on: It simplifies {@link #inferParagraphTags}.
*
*
Note that we do not merge a literal token and a whitespace token together.
*/
private static ImmutableList joinAdjacentLiteralsAndAdjacentWhitespace(List input) {
/*
* Note: Our final token is always END_JAVADOC. This saves us some trouble:
*
* - Our inner while() doesn't need a hasNext() check.
*
* - We don't need to check for leftover accumulated literals after we exit the loop.
*/
ImmutableList.Builder output = ImmutableList.builder();
StringBuilder accumulated = new StringBuilder();
for (PeekingIterator tokens = peekingIterator(input.iterator()); tokens.hasNext(); ) {
if (tokens.peek().getType() == LITERAL) {
accumulated.append(tokens.peek().getValue());
tokens.next();
continue;
}
/*
* IF we have accumulated some literals to join together (say, "foobar"), and IF we'll
* next see whitespace followed by a "@" literal, we need to join that together with the
* previous literals. That ensures that we won't insert a line break before the "@," turning
* it into a tag.
*/
if (accumulated.length() == 0) {
output.add(tokens.peek());
tokens.next();
continue;
}
StringBuilder seenWhitespace = new StringBuilder();
while (tokens.peek().getType() == WHITESPACE) {
seenWhitespace.append(tokens.next().getValue());
}
if (tokens.peek().getType() == LITERAL && tokens.peek().getValue().startsWith("@")) {
// OK, we're in the case described above.
accumulated.append(" ");
accumulated.append(tokens.peek().getValue());
tokens.next();
continue;
}
output.add(new Token(LITERAL, accumulated.toString()));
accumulated.setLength(0);
if (seenWhitespace.length() > 0) {
output.add(new Token(WHITESPACE, seenWhitespace.toString()));
}
// We have another token coming, possibly of type OTHER. Leave it for the next iteration.
}
/*
* TODO(cpovirk): Another case where we could try to join tokens is if a line ends with
* /[^ -]-/, as in "non-\nblocking."
*/
return output.build();
}
/**
* Where the input has two consecutive line breaks between literals, insert a {@code } tag
* between the literals.
*
*
This method must be called after {@link #joinAdjacentLiteralsAndAdjacentWhitespace}, as it
* assumes that adjacent whitespace tokens have already been joined.
*/
private static ImmutableList inferParagraphTags(List input) {
ImmutableList.Builder output = ImmutableList.builder();
for (PeekingIterator tokens = peekingIterator(input.iterator()); tokens.hasNext(); ) {
if (tokens.peek().getType() == LITERAL) {
output.add(tokens.next());
if (tokens.peek().getType() == WHITESPACE
&& hasMultipleNewlines(tokens.peek().getValue())) {
output.add(tokens.next());
if (tokens.peek().getType() == LITERAL) {
output.add(new Token(PARAGRAPH_OPEN_TAG, ""));
}
}
} else {
// TODO(cpovirk): Or just `continue` from the
case and move this out of the `else`?
output.add(tokens.next());
}
}
return output.build();
/*
* Note: We do not want to insert
tags inside
. Fortunately, the formatter gets that
* right without special effort on our part. The reason: Line breaks inside a section are
* of type FORCED_NEWLINE rather than WHITESPACE.
*/
}
/**
* Replaces whitespace after a {@code href=...>} token with an "optional link break." This allows
* us to output either {@code foo} or {@code \nfoo}, depending on
* how much space we have left on the line.
*
* This method must be called after {@link #joinAdjacentLiteralsAndAdjacentWhitespace}, as it
* assumes that adjacent whitespace tokens have already been joined.
*/
private static ImmutableList optionalizeSpacesAfterLinks(List input) {
ImmutableList.Builder output = ImmutableList.builder();
for (PeekingIterator tokens = peekingIterator(input.iterator()); tokens.hasNext(); ) {
if (tokens.peek().getType() == LITERAL && tokens.peek().getValue().matches("^href=[^>]*>")) {
output.add(tokens.next());
if (tokens.peek().getType() == WHITESPACE) {
output.add(new Token(OPTIONAL_LINE_BREAK, tokens.next().getValue()));
}
} else {
output.add(tokens.next());
}
}
return output.build();
/*
* Note: We do not want to insert tags inside
. Fortunately, the formatter gets that
* right without special effort on our part. The reason: Line breaks inside a section are
* of type FORCED_NEWLINE rather than WHITESPACE.
*/
}
/**
* Adjust indentation inside `{@code` blocks.
*
* Also trim leading and trailing blank lines, and move the trailing `}` to its own line.
*/
private static ImmutableList deindentPreCodeBlocks(List input) {
ImmutableList.Builder output = ImmutableList.builder();
for (PeekingIterator tokens = peekingIterator(input.iterator()); tokens.hasNext(); ) {
if (tokens.peek().getType() != PRE_OPEN_TAG) {
output.add(tokens.next());
continue;
}
output.add(tokens.next());
List initialNewlines = new ArrayList<>();
while (tokens.hasNext() && tokens.peek().getType() == FORCED_NEWLINE) {
initialNewlines.add(tokens.next());
}
if (tokens.peek().getType() != LITERAL
|| !tokens.peek().getValue().matches("[ \t]*[{]@code")) {
output.addAll(initialNewlines);
output.add(tokens.next());
continue;
}
deindentPreCodeBlock(output, tokens);
}
return output.build();
}
private static void deindentPreCodeBlock(
ImmutableList.Builder output, PeekingIterator tokens) {
Deque saved = new ArrayDeque<>();
output.add(new Token(LITERAL, tokens.next().getValue().trim()));
while (tokens.hasNext() && tokens.peek().getType() != PRE_CLOSE_TAG) {
Token token = tokens.next();
saved.addLast(token);
}
while (!saved.isEmpty() && saved.peekFirst().getType() == FORCED_NEWLINE) {
saved.removeFirst();
}
while (!saved.isEmpty() && saved.peekLast().getType() == FORCED_NEWLINE) {
saved.removeLast();
}
if (saved.isEmpty()) {
return;
}
// move the trailing `}` to its own line
Token last = saved.peekLast();
boolean trailingBrace = false;
if (last.getType() == LITERAL && last.getValue().endsWith("}")) {
saved.removeLast();
if (last.length() > 1) {
saved.addLast(
new Token(LITERAL, last.getValue().substring(0, last.getValue().length() - 1)));
saved.addLast(new Token(FORCED_NEWLINE, null));
}
trailingBrace = true;
}
int trim = -1;
for (Token token : saved) {
if (token.getType() == LITERAL) {
int idx = CharMatcher.isNot(' ').indexIn(token.getValue());
if (idx != -1 && (trim == -1 || idx < trim)) {
trim = idx;
}
}
}
output.add(new Token(FORCED_NEWLINE, "\n"));
for (Token token : saved) {
if (token.getType() == LITERAL) {
output.add(
new Token(
LITERAL,
trim > 0 && token.length() > trim
? token.getValue().substring(trim)
: token.getValue()));
} else {
output.add(token);
}
}
if (trailingBrace) {
output.add(new Token(LITERAL, "}"));
} else {
output.add(new Token(FORCED_NEWLINE, "\n"));
}
}
private static final CharMatcher NEWLINE = CharMatcher.is('\n');
private static boolean hasMultipleNewlines(String s) {
return NEWLINE.countIn(s) > 1;
}
/*
* This also eats any trailing whitespace. We would be smart enough to ignore that, anyway --
* except in the case of /
, inside which we otherwise leave whitespace intact.
*
* We'd remove the trailing whitespace later on (in JavaCommentsHelper.rewrite), but I feel safer
* stripping it now: It otherwise might confuse our line-length count, which we use for wrapping.
*/
private static final Pattern NEWLINE_PATTERN = compile("^[ \t]*\n[ \t]*[*]?[ \t]?");
// We ensure elsewhere that we match this only at the beginning of a line.
// Only match tags that start with a lowercase letter, to avoid false matches on unescaped
// annotations inside code blocks.
// Match "@param " specially in case the is a or other HTML tag we treat specially.
private static final Pattern FOOTER_TAG_PATTERN = compile("^@(param\\s+<\\w+>|[a-z]\\w*)");
private static final Pattern MOE_BEGIN_STRIP_COMMENT_PATTERN =
compile("^");
private static final Pattern MOE_END_STRIP_COMMENT_PATTERN =
compile("^");
private static final Pattern HTML_COMMENT_PATTERN = fullCommentPattern();
private static final Pattern PRE_OPEN_PATTERN = openTagPattern("pre");
private static final Pattern PRE_CLOSE_PATTERN = closeTagPattern("pre");
private static final Pattern CODE_OPEN_PATTERN = openTagPattern("code");
private static final Pattern CODE_CLOSE_PATTERN = closeTagPattern("code");
private static final Pattern TABLE_OPEN_PATTERN = openTagPattern("table");
private static final Pattern TABLE_CLOSE_PATTERN = closeTagPattern("table");
private static final Pattern LIST_OPEN_PATTERN = openTagPattern("ul|ol|dl");
private static final Pattern LIST_CLOSE_PATTERN = closeTagPattern("ul|ol|dl");
private static final Pattern LIST_ITEM_OPEN_PATTERN = openTagPattern("li|dt|dd");
private static final Pattern LIST_ITEM_CLOSE_PATTERN = closeTagPattern("li|dt|dd");
private static final Pattern HEADER_OPEN_PATTERN = openTagPattern("h[1-6]");
private static final Pattern HEADER_CLOSE_PATTERN = closeTagPattern("h[1-6]");
private static final Pattern PARAGRAPH_OPEN_PATTERN = openTagPattern("p");
private static final Pattern PARAGRAPH_CLOSE_PATTERN = closeTagPattern("p");
private static final Pattern BLOCKQUOTE_OPEN_PATTERN = openTagPattern("blockquote");
private static final Pattern BLOCKQUOTE_CLOSE_PATTERN = closeTagPattern("blockquote");
private static final Pattern BR_PATTERN = openTagPattern("br");
private static final Pattern INLINE_TAG_OPEN_PATTERN = compile("^[{]@\\w*");
/*
* We exclude < so that we don't swallow following HTML tags. This lets us fix up "foo
" (~400
* hits in Google-internal code). We will join unnecessarily split "words" (like "foobar")
* in a later step. There's a similar story for braces. I'm not sure I actually need to exclude @
* or *. TODO(cpovirk): Try removing them.
*
* Thanks to the "rejoin" step in joinAdjacentLiteralsAndAdjacentWhitespace(), we could get away
* with matching only one character here. That would eliminate the need for the regex entirely.
* That might be faster or slower than what we do now.
*/
private static final Pattern LITERAL_PATTERN = compile("^.[^ \t\n@<{}*]*");
private static Pattern fullCommentPattern() {
return compile("^", DOTALL);
}
private static Pattern openTagPattern(String namePattern) {
return compile(format("^<(?:%s)\\b[^>]*>", namePattern), CASE_INSENSITIVE);
}
private static Pattern closeTagPattern(String namePattern) {
return compile(format("^]*>", namePattern), CASE_INSENSITIVE);
}
static class LexException extends Exception {}
}
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