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A Java source code formatter that follows Google Java Style.
/*
* Copyright 2015 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;
import static java.lang.Math.max;
import static java.lang.Math.min;
import com.google.common.base.MoreObjects;
import com.google.common.base.Preconditions;
import com.google.common.base.Predicate;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multimap;
import com.google.googlejavaformat.Indent.Const;
import com.google.googlejavaformat.Input.Tok;
import com.google.googlejavaformat.Input.Token;
import com.google.googlejavaformat.Output.BreakTag;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
/**
* An {@code OpsBuilder} creates a list of {@link Op}s, which is turned into a {@link Doc} by {@link
* DocBuilder}.
*/
public final class OpsBuilder {
/** @return the actual size of the AST node at position, including comments. */
public int actualSize(int position, int length) {
Token startToken = input.getPositionTokenMap().get(position);
int start = startToken.getTok().getPosition();
for (Tok tok : startToken.getToksBefore()) {
if (tok.isComment()) {
start = min(start, tok.getPosition());
}
}
Token endToken = input.getPositionTokenMap().get(position + length - 1);
int end = endToken.getTok().getPosition() + endToken.getTok().length();
for (Tok tok : endToken.getToksAfter()) {
if (tok.isComment()) {
end = max(end, tok.getPosition() + tok.length());
}
}
return end - start;
}
/** @return the start column of the token at {@code position}, including leading comments. */
public Integer actualStartColumn(int position) {
Token startToken = input.getPositionTokenMap().get(position);
int start = startToken.getTok().getPosition();
int line0 = input.getLineNumber(start);
for (Tok tok : startToken.getToksBefore()) {
if (line0 != input.getLineNumber(tok.getPosition())) {
return start;
}
if (tok.isComment()) {
start = min(start, tok.getPosition());
}
}
return start;
}
/** A request to add or remove a blank line in the output. */
public abstract static class BlankLineWanted {
/** Always emit a blank line. */
public static final BlankLineWanted YES = new SimpleBlankLine(Optional.of(true));
/** Never emit a blank line. */
public static final BlankLineWanted NO = new SimpleBlankLine(Optional.of(false));
/**
* Explicitly preserve blank lines from the input (e.g. before the first member in a class
* declaration). Overrides conditional blank lines.
*/
public static final BlankLineWanted PRESERVE =
new SimpleBlankLine(/* wanted= */ Optional.empty());
/** Is the blank line wanted? */
public abstract Optional wanted();
/** Merge this blank line request with another. */
public abstract BlankLineWanted merge(BlankLineWanted wanted);
/** Emit a blank line if the given break is taken. */
public static BlankLineWanted conditional(BreakTag breakTag) {
return new ConditionalBlankLine(ImmutableList.of(breakTag));
}
private static final class SimpleBlankLine extends BlankLineWanted {
private final Optional wanted;
SimpleBlankLine(Optional wanted) {
this.wanted = wanted;
}
@Override
public Optional wanted() {
return wanted;
}
@Override
public BlankLineWanted merge(BlankLineWanted other) {
return this;
}
}
private static final class ConditionalBlankLine extends BlankLineWanted {
private final ImmutableList tags;
ConditionalBlankLine(Iterable tags) {
this.tags = ImmutableList.copyOf(tags);
}
@Override
public Optional wanted() {
for (BreakTag tag : tags) {
if (tag.wasBreakTaken()) {
return Optional.of(true);
}
}
return Optional.empty();
}
@Override
public BlankLineWanted merge(BlankLineWanted other) {
if (!(other instanceof ConditionalBlankLine)) {
return other;
}
return new ConditionalBlankLine(
Iterables.concat(this.tags, ((ConditionalBlankLine) other).tags));
}
}
}
private final Input input;
private final List ops = new ArrayList<>();
private final Output output;
private static final Indent.Const ZERO = Indent.Const.ZERO;
private int tokenI = 0;
private int inputPosition = Integer.MIN_VALUE;
/** The number of unclosed open ops in the input stream. */
int depth = 0;
/** Add an {@link Op}, and record open/close ops for later validation of unclosed levels. */
public final void add(Op op) {
if (op instanceof OpenOp) {
depth++;
} else if (op instanceof CloseOp) {
depth--;
if (depth < 0) {
throw new AssertionError();
}
}
ops.add(op);
}
/** Add a list of {@link Op}s. */
public final void addAll(List ops) {
for (Op op : ops) {
add(op);
}
}
/**
* The {@code OpsBuilder} constructor.
*
* @param input the {@link Input}, used for retrieve information from the AST
* @param output the {@link Output}, used here only to record blank-line information
*/
public OpsBuilder(Input input, Output output) {
this.input = input;
this.output = output;
}
/** Get the {@code OpsBuilder}'s {@link Input}. */
public final Input getInput() {
return input;
}
/** Returns the number of unclosed open ops in the input stream. */
public int depth() {
return depth;
}
/**
* Checks that all open ops in the op stream have matching close ops.
*
* @throws FormattingError if any ops were unclosed
*/
public void checkClosed(int previous) {
if (depth != previous) {
throw new FormattingError(diagnostic(String.format("saw %d unclosed ops", depth)));
}
}
/** Create a {@link FormatterDiagnostic} at the current position. */
public FormatterDiagnostic diagnostic(String message) {
return input.createDiagnostic(inputPosition, message);
}
/**
* Sync to position in the input. If we've skipped outputting any tokens that were present in the
* input tokens, output them here and optionally complain.
*
* @param inputPosition the {@code 0}-based input position
*/
public final void sync(int inputPosition) {
if (inputPosition > this.inputPosition) {
ImmutableList tokens = input.getTokens();
int tokensN = tokens.size();
this.inputPosition = inputPosition;
if (tokenI < tokensN && inputPosition > tokens.get(tokenI).getTok().getPosition()) {
// Found a missing input token. Insert it and mark it missing (usually not good).
Input.Token token = tokens.get(tokenI++);
throw new FormattingError(
diagnostic(String.format("did not generate token \"%s\"", token.getTok().getText())));
}
}
}
/** Output any remaining tokens from the input stream (e.g. terminal whitespace). */
public final void drain() {
int inputPosition = input.getText().length() + 1;
if (inputPosition > this.inputPosition) {
ImmutableList tokens = input.getTokens();
int tokensN = tokens.size();
while (tokenI < tokensN && inputPosition > tokens.get(tokenI).getTok().getPosition()) {
Input.Token token = tokens.get(tokenI++);
add(
Doc.Token.make(
token,
Doc.Token.RealOrImaginary.IMAGINARY,
ZERO,
/* breakAndIndentTrailingComment= */ Optional.empty()));
}
}
this.inputPosition = inputPosition;
checkClosed(0);
}
/**
* Open a new level by emitting an {@link OpenOp}.
*
* @param plusIndent the extra indent for the new level
*/
public final void open(Indent plusIndent) {
add(OpenOp.make(plusIndent));
}
/** Close the current level, by emitting a {@link CloseOp}. */
public final void close() {
add(CloseOp.make());
}
/** Return the text of the next {@link Input.Token}, or absent if there is none. */
public final Optional peekToken() {
return peekToken(0);
}
/** Return the text of an upcoming {@link Input.Token}, or absent if there is none. */
public final Optional peekToken(int skip) {
ImmutableList tokens = input.getTokens();
int idx = tokenI + skip;
return idx < tokens.size()
? Optional.of(tokens.get(idx).getTok().getOriginalText())
: Optional.empty();
}
/**
* Returns the {@link Input.Tok}s starting at the current source position, which are satisfied by
* the given predicate.
*/
public ImmutableList peekTokens(int startPosition, Predicate predicate) {
ImmutableList tokens = input.getTokens();
Preconditions.checkState(
tokens.get(tokenI).getTok().getPosition() == startPosition,
"Expected the current token to be at position %s, found: %s",
startPosition,
tokens.get(tokenI));
ImmutableList.Builder result = ImmutableList.builder();
for (int idx = tokenI; idx < tokens.size(); idx++) {
Tok tok = tokens.get(idx).getTok();
if (!predicate.apply(tok)) {
break;
}
result.add(tok);
}
return result.build();
}
/**
* Emit an optional token iff it exists on the input. This is used to emit tokens whose existence
* has been lost in the AST.
*
* @param token the optional token
*/
public final void guessToken(String token) {
token(
token,
Doc.Token.RealOrImaginary.IMAGINARY,
ZERO,
/* breakAndIndentTrailingComment= */ Optional.empty());
}
public final void token(
String token,
Doc.Token.RealOrImaginary realOrImaginary,
Indent plusIndentCommentsBefore,
Optional breakAndIndentTrailingComment) {
ImmutableList tokens = input.getTokens();
if (token.equals(peekToken().orElse(null))) { // Found the input token. Output it.
add(
Doc.Token.make(
tokens.get(tokenI++),
Doc.Token.RealOrImaginary.REAL,
plusIndentCommentsBefore,
breakAndIndentTrailingComment));
} else {
/*
* Generated a "bad" token, which doesn't exist on the input. Drop it, and complain unless
* (for example) we're guessing at an optional token.
*/
if (realOrImaginary.isReal()) {
throw new FormattingError(
diagnostic(
String.format(
"expected token: '%s'; generated %s instead",
peekToken().orElse(null), token)));
}
}
}
/**
* Emit a single- or multi-character op by breaking it into single-character {@link Doc.Token}s.
*
* @param op the operator to emit
*/
public final void op(String op) {
int opN = op.length();
for (int i = 0; i < opN; i++) {
token(
op.substring(i, i + 1),
Doc.Token.RealOrImaginary.REAL,
ZERO,
/* breakAndIndentTrailingComment= */ Optional.empty());
}
}
/** Emit a {@link Doc.Space}. */
public final void space() {
add(Doc.Space.make());
}
/** Emit a {@link Doc.Break}. */
public final void breakOp() {
breakOp(Doc.FillMode.UNIFIED, "", ZERO);
}
/**
* Emit a {@link Doc.Break}.
*
* @param plusIndent extra indent if taken
*/
public final void breakOp(Indent plusIndent) {
breakOp(Doc.FillMode.UNIFIED, "", plusIndent);
}
/** Emit a filled {@link Doc.Break}. */
public final void breakToFill() {
breakOp(Doc.FillMode.INDEPENDENT, "", ZERO);
}
/** Emit a forced {@link Doc.Break}. */
public final void forcedBreak() {
breakOp(Doc.FillMode.FORCED, "", ZERO);
}
/**
* Emit a forced {@link Doc.Break}.
*
* @param plusIndent extra indent if taken
*/
public final void forcedBreak(Indent plusIndent) {
breakOp(Doc.FillMode.FORCED, "", plusIndent);
}
/**
* Emit a {@link Doc.Break}, with a specified {@code flat} value (e.g., {@code " "}).
*
* @param flat the {@link Doc.Break} when not broken
*/
public final void breakOp(String flat) {
breakOp(Doc.FillMode.UNIFIED, flat, ZERO);
}
/**
* Emit a {@link Doc.Break}, with a specified {@code flat} value (e.g., {@code " "}).
*
* @param flat the {@link Doc.Break} when not broken
*/
public final void breakToFill(String flat) {
breakOp(Doc.FillMode.INDEPENDENT, flat, ZERO);
}
/**
* Emit a generic {@link Doc.Break}.
*
* @param fillMode the {@link Doc.FillMode}
* @param flat the {@link Doc.Break} when not broken
* @param plusIndent extra indent if taken
*/
public final void breakOp(Doc.FillMode fillMode, String flat, Indent plusIndent) {
breakOp(fillMode, flat, plusIndent, /* optionalTag= */ Optional.empty());
}
/**
* Emit a generic {@link Doc.Break}.
*
* @param fillMode the {@link Doc.FillMode}
* @param flat the {@link Doc.Break} when not broken
* @param plusIndent extra indent if taken
* @param optionalTag an optional tag for remembering whether the break was taken
*/
public final void breakOp(
Doc.FillMode fillMode, String flat, Indent plusIndent, Optional optionalTag) {
add(Doc.Break.make(fillMode, flat, plusIndent, optionalTag));
}
private int lastPartialFormatBoundary = -1;
/**
* Make the boundary of a region that can be partially formatted. The boundary will be included in
* the following region, e.g.: [[boundary0, boundary1), [boundary1, boundary2), ...].
*/
public void markForPartialFormat() {
if (lastPartialFormatBoundary == -1) {
lastPartialFormatBoundary = tokenI;
return;
}
if (tokenI == lastPartialFormatBoundary) {
return;
}
Token start = input.getTokens().get(lastPartialFormatBoundary);
Token end = input.getTokens().get(tokenI - 1);
output.markForPartialFormat(start, end);
lastPartialFormatBoundary = tokenI;
}
/**
* Force or suppress a blank line here in the output.
*
* @param wanted whether to force ({@code true}) or suppress {@code false}) the blank line
*/
public final void blankLineWanted(BlankLineWanted wanted) {
output.blankLine(getI(input.getTokens().get(tokenI)), wanted);
}
private static int getI(Input.Token token) {
for (Input.Tok tok : token.getToksBefore()) {
if (tok.getIndex() >= 0) {
return tok.getIndex();
}
}
return token.getTok().getIndex();
}
private static final Doc.Space SPACE = Doc.Space.make();
/**
* Build a list of {@link Op}s from the {@code OpsBuilder}.
*
* @return the list of {@link Op}s
*/
public final ImmutableList build() {
markForPartialFormat();
// Rewrite the ops to insert comments.
Multimap tokOps = ArrayListMultimap.create();
int opsN = ops.size();
for (int i = 0; i < opsN; i++) {
Op op = ops.get(i);
if (op instanceof Doc.Token) {
/*
* Token ops can have associated non-tokens, including comments, which we need to insert.
* They can also cause line breaks, so we insert them before or after the current level,
* when possible.
*/
Doc.Token tokenOp = (Doc.Token) op;
Input.Token token = tokenOp.getToken();
int j = i; // Where to insert toksBefore before.
while (0 < j && ops.get(j - 1) instanceof OpenOp) {
--j;
}
int k = i; // Where to insert toksAfter after.
while (k + 1 < opsN && ops.get(k + 1) instanceof CloseOp) {
++k;
}
if (tokenOp.realOrImaginary().isReal()) {
/*
* Regular input token. Copy out toksBefore before token, and toksAfter after it. Insert
* this token's toksBefore at position j.
*/
int newlines = 0; // Count of newlines in a row.
boolean space = false; // Do we need an extra space after a previous "/*" comment?
boolean lastWasComment = false; // Was the last thing we output a comment?
boolean allowBlankAfterLastComment = false;
for (Input.Tok tokBefore : token.getToksBefore()) {
if (tokBefore.isNewline()) {
newlines++;
} else if (tokBefore.isComment()) {
tokOps.put(
j,
Doc.Break.make(
tokBefore.isSlashSlashComment() ? Doc.FillMode.FORCED : Doc.FillMode.UNIFIED,
"",
tokenOp.getPlusIndentCommentsBefore()));
tokOps.putAll(j, makeComment(tokBefore));
space = tokBefore.isSlashStarComment();
newlines = 0;
lastWasComment = true;
if (tokBefore.isJavadocComment()) {
tokOps.put(j, Doc.Break.makeForced());
}
allowBlankAfterLastComment =
tokBefore.isSlashSlashComment()
|| (tokBefore.isSlashStarComment() && !tokBefore.isJavadocComment());
}
}
if (allowBlankAfterLastComment && newlines > 1) {
// Force a line break after two newlines in a row following a line or block comment
output.blankLine(token.getTok().getIndex(), BlankLineWanted.YES);
}
if (lastWasComment && newlines > 0) {
tokOps.put(j, Doc.Break.makeForced());
} else if (space) {
tokOps.put(j, SPACE);
}
// Now we've seen the Token; output the toksAfter.
for (Input.Tok tokAfter : token.getToksAfter()) {
if (tokAfter.isComment()) {
boolean breakAfter =
tokAfter.isJavadocComment()
|| (tokAfter.isSlashStarComment()
&& tokenOp.breakAndIndentTrailingComment().isPresent());
if (breakAfter) {
tokOps.put(
k + 1,
Doc.Break.make(
Doc.FillMode.FORCED,
"",
tokenOp.breakAndIndentTrailingComment().orElse(Const.ZERO)));
} else {
tokOps.put(k + 1, SPACE);
}
tokOps.putAll(k + 1, makeComment(tokAfter));
if (breakAfter) {
tokOps.put(k + 1, Doc.Break.make(Doc.FillMode.FORCED, "", ZERO));
}
}
}
} else {
/*
* This input token was mistakenly not generated for output. As no whitespace or comments
* were generated (presumably), copy all input non-tokens literally, even spaces and
* newlines.
*/
int newlines = 0;
boolean lastWasComment = false;
for (Input.Tok tokBefore : token.getToksBefore()) {
if (tokBefore.isNewline()) {
newlines++;
} else if (tokBefore.isComment()) {
newlines = 0;
lastWasComment = tokBefore.isComment();
}
if (lastWasComment && newlines > 0) {
tokOps.put(j, Doc.Break.makeForced());
}
tokOps.put(j, Doc.Tok.make(tokBefore));
}
for (Input.Tok tokAfter : token.getToksAfter()) {
tokOps.put(k + 1, Doc.Tok.make(tokAfter));
}
}
}
}
/*
* Construct new list of ops, splicing in the comments. If a comment is inserted immediately
* before a space, suppress the space.
*/
ImmutableList.Builder newOps = ImmutableList.builder();
boolean afterForcedBreak = false; // Was the last Op a forced break? If so, suppress spaces.
for (int i = 0; i < opsN; i++) {
for (Op op : tokOps.get(i)) {
if (!(afterForcedBreak && op instanceof Doc.Space)) {
newOps.add(op);
afterForcedBreak = isForcedBreak(op);
}
}
Op op = ops.get(i);
if (afterForcedBreak
&& (op instanceof Doc.Space
|| (op instanceof Doc.Break
&& ((Doc.Break) op).getPlusIndent() == 0
&& " ".equals(((Doc) op).getFlat())))) {
continue;
}
newOps.add(op);
if (!(op instanceof OpenOp)) {
afterForcedBreak = isForcedBreak(op);
}
}
for (Op op : tokOps.get(opsN)) {
if (!(afterForcedBreak && op instanceof Doc.Space)) {
newOps.add(op);
afterForcedBreak = isForcedBreak(op);
}
}
return newOps.build();
}
private static boolean isForcedBreak(Op op) {
return op instanceof Doc.Break && ((Doc.Break) op).isForced();
}
private static List makeComment(Input.Tok comment) {
return comment.isSlashStarComment()
? ImmutableList.of(Doc.Tok.make(comment))
: ImmutableList.of(Doc.Tok.make(comment), Doc.Break.makeForced());
}
@Override
public final String toString() {
return MoreObjects.toStringHelper(this)
.add("input", input)
.add("ops", ops)
.add("output", output)
.add("tokenI", tokenI)
.add("inputPosition", inputPosition)
.toString();
}
}