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Make AppliedFix more efficient
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PiperOrigin-RevId: 439646636
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cushon authored and Error Prone Team committed Apr 5, 2022
1 parent fe05664 commit 6563215
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Showing 2 changed files with 27 additions and 10 deletions.
Original file line number Diff line number Diff line change
Expand Up @@ -83,7 +83,8 @@ private JavacErrorDescriptionListener(
checkNotNull(endPositions);
try {
CharSequence sourceFileContent = sourceFile.getCharContent(true);
fixToAppliedFix = fix -> AppliedFix.fromSource(sourceFileContent, endPositions).apply(fix);
AppliedFix.Applier applier = AppliedFix.fromSource(sourceFileContent, endPositions);
fixToAppliedFix = applier::apply;
} catch (IOException e) {
throw new UncheckedIOException(e);
}
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Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,18 @@

import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.base.Supplier;
import com.google.common.base.Suppliers;
import com.sun.tools.javac.tree.EndPosTable;
import java.io.IOException;
import java.io.LineNumberReader;
import java.io.StringReader;
import java.util.HashSet;
import java.util.NavigableMap;
import java.util.Set;
import java.util.TreeMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.annotation.Nullable;

/**
Expand Down Expand Up @@ -52,10 +58,12 @@ public boolean isRemoveLine() {
public static class Applier {
private final CharSequence source;
private final EndPosTable endPositions;
private final Supplier<NavigableMap<Integer, Integer>> lineOffsets;

public Applier(CharSequence source, EndPosTable endPositions) {
this.source = source;
this.endPositions = endPositions;
this.lineOffsets = Suppliers.memoize(() -> lineOffsets(source.toString()));
}

/**
Expand All @@ -80,15 +88,7 @@ public AppliedFix apply(Fix suggestedFix) {
replaced.replace(repl.startPosition(), repl.endPosition(), repl.replaceWith());

// Find the line number(s) being modified
// TODO: this could be more efficient
try {
LineNumberReader lineNumberReader =
new LineNumberReader(new StringReader(source.toString()));
lineNumberReader.skip(repl.startPosition());
modifiedLines.add(lineNumberReader.getLineNumber());
} catch (IOException e) {
// impossible since source is in-memory
}
modifiedLines.add(lineOffsets.get().floorEntry(repl.startPosition()).getValue());
}

// Not sure this is really the right behavior, but otherwise we can end up with an infinite
Expand Down Expand Up @@ -138,4 +138,20 @@ private static Set<Replacement> descending(Set<Replacement> set) {
public static Applier fromSource(CharSequence source, EndPosTable endPositions) {
return new Applier(source, endPositions);
}

private static final Pattern NEWLINE = Pattern.compile("\\R");

/** Returns the start offsets of the lines in the input. */
private static NavigableMap<Integer, Integer> lineOffsets(String input) {
NavigableMap<Integer, Integer> lines = new TreeMap<>();
int line = 0;
int idx = 0;
lines.put(idx, line++);
Matcher matcher = NEWLINE.matcher(input);
while (matcher.find(idx)) {
idx = matcher.end();
lines.put(idx, line++);
}
return lines;
}
}

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