diff options
Diffstat (limited to 'src/main/java/com/google/devtools/build/lib/query2/engine/BinaryOperatorExpression.java')
-rw-r--r-- | src/main/java/com/google/devtools/build/lib/query2/engine/BinaryOperatorExpression.java | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/query2/engine/BinaryOperatorExpression.java b/src/main/java/com/google/devtools/build/lib/query2/engine/BinaryOperatorExpression.java new file mode 100644 index 0000000000..e5e600f831 --- /dev/null +++ b/src/main/java/com/google/devtools/build/lib/query2/engine/BinaryOperatorExpression.java @@ -0,0 +1,93 @@ +// Copyright 2014 Google Inc. All rights reserved. +// +// 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.devtools.build.lib.query2.engine; + +import com.google.common.base.Preconditions; +import com.google.common.collect.ImmutableList; + +import java.util.Collection; +import java.util.LinkedHashSet; +import java.util.List; +import java.util.Set; + +/** + * A binary algebraic set operation. + * + * <pre> + * expr ::= expr (INTERSECT expr)+ + * | expr ('^' expr)+ + * | expr (UNION expr)+ + * | expr ('+' expr)+ + * | expr (EXCEPT expr)+ + * | expr ('-' expr)+ + * </pre> + */ +class BinaryOperatorExpression extends QueryExpression { + + private final Lexer.TokenKind operator; // ::= INTERSECT/CARET | UNION/PLUS | EXCEPT/MINUS + private final ImmutableList<QueryExpression> operands; + + BinaryOperatorExpression(Lexer.TokenKind operator, + List<QueryExpression> operands) { + Preconditions.checkState(operands.size() > 1); + this.operator = operator; + this.operands = ImmutableList.copyOf(operands); + } + + @Override + public <T> Set<T> eval(QueryEnvironment<T> env) throws QueryException { + Set<T> lhsValue = new LinkedHashSet<>(operands.get(0).eval(env)); + + for (int i = 1; i < operands.size(); i++) { + Set<T> rhsValue = operands.get(i).eval(env); + switch (operator) { + case INTERSECT: + case CARET: + lhsValue.retainAll(rhsValue); + break; + case UNION: + case PLUS: + lhsValue.addAll(rhsValue); + break; + case EXCEPT: + case MINUS: + lhsValue.removeAll(rhsValue); + break; + default: + throw new IllegalStateException("operator=" + operator); + } + } + return lhsValue; + } + + @Override + public void collectTargetPatterns(Collection<String> literals) { + for (QueryExpression subExpression : operands) { + subExpression.collectTargetPatterns(literals); + } + } + + @Override + public String toString() { + StringBuilder result = new StringBuilder(); + for (int i = 1; i < operands.size(); i++) { + result.append("("); + } + result.append(operands.get(0)); + for (int i = 1; i < operands.size(); i++) { + result.append(" " + operator.getPrettyName() + " " + operands.get(i) + ")"); + } + return result.toString(); + } +} |