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| 1 | +package com.google.googlejavaformat.java; |
| 2 | + |
| 3 | +import com.google.common.collect.ImmutableList; |
| 4 | +import com.google.common.collect.Range; |
| 5 | +import com.google.common.collect.RangeMap; |
| 6 | +import com.google.common.collect.TreeRangeMap; |
| 7 | +import com.sun.source.tree.*; |
| 8 | +import com.sun.source.util.JavacTask; |
| 9 | +import com.sun.source.util.SourcePositions; |
| 10 | +import com.sun.source.util.TreePath; |
| 11 | +import com.sun.source.util.TreePathScanner; |
| 12 | +import com.sun.source.util.Trees; |
| 13 | +import com.sun.tools.javac.api.JavacTool; |
| 14 | +import com.sun.tools.javac.file.JavacFileManager; |
| 15 | +import com.sun.tools.javac.util.Context; |
| 16 | + |
| 17 | +import javax.lang.model.element.Modifier; |
| 18 | +import javax.tools.Diagnostic; |
| 19 | +import javax.tools.DiagnosticCollector; |
| 20 | +import javax.tools.JavaFileObject; |
| 21 | +import javax.tools.SimpleJavaFileObject; |
| 22 | +import java.io.IOException; |
| 23 | +import java.net.URI; |
| 24 | +import java.util.*; |
| 25 | +import java.util.stream.Collectors; |
| 26 | + |
| 27 | +/** |
| 28 | + * Removes unused declarations from Java source code, including: |
| 29 | + * - Redundant modifiers in interfaces (public, static, final, abstract) |
| 30 | + * - Redundant modifiers in classes, enums, and annotations |
| 31 | + * - Redundant final modifiers on method parameters (preserved now) |
| 32 | + */ |
| 33 | +public class RemoveUnusedDeclarations { |
| 34 | + public static String removeUnusedDeclarations(String source) throws FormatterException { |
| 35 | + DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>(); |
| 36 | + var task = JavacTool.create().getTask( |
| 37 | + null, |
| 38 | + new JavacFileManager(new Context(), true, null), |
| 39 | + diagnostics, |
| 40 | + ImmutableList.of("-Xlint:-processing"), |
| 41 | + null, |
| 42 | + ImmutableList.of((JavaFileObject) new SimpleJavaFileObject(URI.create("source"), |
| 43 | + JavaFileObject.Kind.SOURCE) { |
| 44 | + @Override |
| 45 | + public CharSequence getCharContent(boolean ignoreEncodingErrors) { |
| 46 | + return source; |
| 47 | + } |
| 48 | + })); |
| 49 | + |
| 50 | + try { |
| 51 | + Iterable<? extends CompilationUnitTree> units = task.parse(); |
| 52 | + if (!units.iterator().hasNext()) { |
| 53 | + throw new FormatterException("No compilation units found"); |
| 54 | + } |
| 55 | + |
| 56 | + for (Diagnostic<? extends JavaFileObject> diagnostic : diagnostics.getDiagnostics()) { |
| 57 | + if (diagnostic.getKind() == Diagnostic.Kind.ERROR) { |
| 58 | + throw new FormatterException("Syntax error in source: " + diagnostic.getMessage(null)); |
| 59 | + } |
| 60 | + } |
| 61 | + |
| 62 | + var scanner = new UnusedDeclarationScanner(task); |
| 63 | + scanner.scan(units.iterator().next(), null); |
| 64 | + |
| 65 | + return applyReplacements(source, scanner.getReplacements()); |
| 66 | + } catch (IOException e) { |
| 67 | + throw new FormatterException("Error processing source file: " + e.getMessage()); |
| 68 | + } |
| 69 | + } |
| 70 | + |
| 71 | + private static class UnusedDeclarationScanner extends TreePathScanner<Void, Void> { |
| 72 | + private final RangeMap<Integer, String> replacements = TreeRangeMap.create(); |
| 73 | + private final SourcePositions sourcePositions; |
| 74 | + private final Trees trees; |
| 75 | + |
| 76 | + private static final ImmutableList<Modifier> CANONICAL_MODIFIER_ORDER = ImmutableList.of( |
| 77 | + Modifier.PUBLIC, Modifier.PROTECTED, Modifier.PRIVATE, |
| 78 | + Modifier.ABSTRACT, Modifier.STATIC, Modifier.FINAL, |
| 79 | + Modifier.TRANSIENT, Modifier.VOLATILE, Modifier.SYNCHRONIZED, |
| 80 | + Modifier.NATIVE, Modifier.STRICTFP |
| 81 | + ); |
| 82 | + |
| 83 | + private UnusedDeclarationScanner(JavacTask task) { |
| 84 | + this.sourcePositions = Trees.instance(task).getSourcePositions(); |
| 85 | + this.trees = Trees.instance(task); |
| 86 | + } |
| 87 | + |
| 88 | + public RangeMap<Integer, String> getReplacements() { |
| 89 | + return replacements; |
| 90 | + } |
| 91 | + |
| 92 | + @Override |
| 93 | + public Void visitClass(ClassTree node, Void unused) { |
| 94 | + var parentPath = getCurrentPath().getParentPath(); |
| 95 | + if (node.getKind() == Tree.Kind.INTERFACE) { |
| 96 | + checkForRedundantModifiers(node, Set.of(Modifier.PUBLIC, Modifier.ABSTRACT)); |
| 97 | + } else if ((parentPath != null ? parentPath.getLeaf().getKind() : null) == Tree.Kind.INTERFACE) { |
| 98 | + checkForRedundantModifiers(node, Set.of(Modifier.PUBLIC, Modifier.STATIC)); |
| 99 | + } else if (node.getKind() == Tree.Kind.ANNOTATION_TYPE) { |
| 100 | + checkForRedundantModifiers(node, Set.of(Modifier.ABSTRACT)); |
| 101 | + } else { |
| 102 | + checkForRedundantModifiers(node, Set.of()); // Always sort |
| 103 | + } |
| 104 | + |
| 105 | + return super.visitClass(node, unused); |
| 106 | + } |
| 107 | + |
| 108 | + @Override |
| 109 | + public Void visitMethod(MethodTree node, Void unused) { |
| 110 | + var parentPath = getCurrentPath().getParentPath(); |
| 111 | + var parentKind = parentPath != null ? parentPath.getLeaf().getKind() : null; |
| 112 | + |
| 113 | + if (parentKind == Tree.Kind.INTERFACE) { |
| 114 | + if (!node.getModifiers().getFlags().contains(Modifier.DEFAULT) && |
| 115 | + !node.getModifiers().getFlags().contains(Modifier.STATIC)) { |
| 116 | + checkForRedundantModifiers(node, Set.of(Modifier.PUBLIC, Modifier.ABSTRACT)); |
| 117 | + } else { |
| 118 | + checkForRedundantModifiers(node, Set.of()); |
| 119 | + } |
| 120 | + } else if (parentKind == Tree.Kind.ANNOTATION_TYPE) { |
| 121 | + checkForRedundantModifiers(node, Set.of(Modifier.ABSTRACT)); |
| 122 | + } else { |
| 123 | + checkForRedundantModifiers(node, Set.of()); // Always sort |
| 124 | + } |
| 125 | + |
| 126 | + return super.visitMethod(node, unused); |
| 127 | + } |
| 128 | + |
| 129 | + @Override |
| 130 | + public Void visitVariable(VariableTree node, Void unused) { |
| 131 | + var parentPath = getCurrentPath().getParentPath(); |
| 132 | + var parentKind = parentPath != null ? parentPath.getLeaf().getKind() : null; |
| 133 | + |
| 134 | + if (node.getKind() == Tree.Kind.ENUM) { |
| 135 | + return super.visitVariable(node, unused); |
| 136 | + } |
| 137 | + |
| 138 | + if (parentKind == Tree.Kind.INTERFACE || parentKind == Tree.Kind.ANNOTATION_TYPE) { |
| 139 | + checkForRedundantModifiers(node, Set.of(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)); |
| 140 | + } else { |
| 141 | + checkForRedundantModifiers(node, Set.of()); // Always sort |
| 142 | + } |
| 143 | + |
| 144 | + return super.visitVariable(node, unused); |
| 145 | + } |
| 146 | + |
| 147 | + private void checkForRedundantModifiers(Tree node, Set<Modifier> redundantModifiers) { |
| 148 | + var modifiers = getModifiers(node); |
| 149 | + if (modifiers == null) return; |
| 150 | + try { |
| 151 | + addReplacementForModifiers(node, new LinkedHashSet<>(modifiers.getFlags()).stream() |
| 152 | + .filter(redundantModifiers::contains) |
| 153 | + .collect(Collectors.toSet())); |
| 154 | + } catch (IOException e) { |
| 155 | + throw new RuntimeException(e); |
| 156 | + } |
| 157 | + } |
| 158 | + |
| 159 | + private ModifiersTree getModifiers(Tree node) { |
| 160 | + if (node instanceof ClassTree) return ((ClassTree) node).getModifiers(); |
| 161 | + if (node instanceof MethodTree) return ((MethodTree) node).getModifiers(); |
| 162 | + if (node instanceof VariableTree) return ((VariableTree) node).getModifiers(); |
| 163 | + return null; |
| 164 | + } |
| 165 | + |
| 166 | + private void addReplacementForModifiers(Tree node, Set<Modifier> toRemove) throws IOException { |
| 167 | + TreePath path = trees.getPath(getCurrentPath().getCompilationUnit(), node); |
| 168 | + if (path == null) return; |
| 169 | + |
| 170 | + CompilationUnitTree unit = path.getCompilationUnit(); |
| 171 | + String source = unit.getSourceFile().getCharContent(true).toString(); |
| 172 | + |
| 173 | + ModifiersTree modifiers = getModifiers(node); |
| 174 | + if (modifiers == null) return; |
| 175 | + |
| 176 | + long modifiersStart = sourcePositions.getStartPosition(unit, modifiers); |
| 177 | + long modifiersEnd = sourcePositions.getEndPosition(unit, modifiers); |
| 178 | + if (modifiersStart == -1 || modifiersEnd == -1) return; |
| 179 | + |
| 180 | + String newModifiersText = modifiers.getFlags().stream() |
| 181 | + .filter(m -> !toRemove.contains(m)) |
| 182 | + .collect(Collectors.toCollection(LinkedHashSet::new)).stream() |
| 183 | + .sorted(Comparator.comparingInt(mod -> { |
| 184 | + int idx = CANONICAL_MODIFIER_ORDER.indexOf(mod); |
| 185 | + return idx == -1 ? Integer.MAX_VALUE : idx; |
| 186 | + })) |
| 187 | + .map(Modifier::toString) |
| 188 | + .collect(Collectors.joining(" ")); |
| 189 | + |
| 190 | + long annotationsEnd = modifiersStart; |
| 191 | + for (AnnotationTree annotation : modifiers.getAnnotations()) { |
| 192 | + long end = sourcePositions.getEndPosition(unit, annotation); |
| 193 | + if (end > annotationsEnd) annotationsEnd = end; |
| 194 | + } |
| 195 | + |
| 196 | + int effectiveStart = (int) annotationsEnd; |
| 197 | + while (effectiveStart < modifiersEnd && Character.isWhitespace(source.charAt(effectiveStart))) { |
| 198 | + effectiveStart++; |
| 199 | + } |
| 200 | + |
| 201 | + String current = source.substring(effectiveStart, (int) modifiersEnd); |
| 202 | + if (!newModifiersText.trim().equals(current.trim())) { |
| 203 | + int globalEnd = (int) modifiersEnd; |
| 204 | + if (newModifiersText.isEmpty()) { |
| 205 | + while (globalEnd < source.length() && Character.isWhitespace(source.charAt(globalEnd))) { |
| 206 | + globalEnd++; |
| 207 | + } |
| 208 | + } |
| 209 | + replacements.put(Range.closedOpen(effectiveStart, globalEnd), newModifiersText); |
| 210 | + } |
| 211 | + } |
| 212 | + } |
| 213 | + |
| 214 | + private static String applyReplacements(String source, RangeMap<Integer, String> replacements) { |
| 215 | + StringBuilder sb = new StringBuilder(source); |
| 216 | + for (Map.Entry<Range<Integer>, String> entry : replacements.asDescendingMapOfRanges().entrySet()) { |
| 217 | + Range<Integer> range = entry.getKey(); |
| 218 | + sb.replace(range.lowerEndpoint(), range.upperEndpoint(), entry.getValue()); |
| 219 | + } |
| 220 | + return sb.toString(); |
| 221 | + } |
| 222 | +} |
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