/*
* Copyright 2015-present Facebook, 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.facebook.buck.intellij.ideabuck.util;
import com.google.common.base.Function;
import com.google.common.collect.ImmutableSet;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Optional;
import java.util.Set;
import javax.annotation.Nullable;
/** Methods for finding files. */
public class FileFinder {
/** Filter that checks that a file exists. */
public static final Function<Path, Boolean> EXISTS = path -> Files.exists(path);
/** Filter that tests if a file is a regular file. */
public static final Function<Path, Boolean> IS_REGULAR_FILE = path -> Files.isRegularFile(path);
/**
* Combines prefixes, base, and suffixes to create a set of file names.
*
* @param prefixes set of prefixes. May be null or empty.
* @param base base name. May be empty.
* @param suffixes set of suffixes. May be null or empty.
* @return a set containing all combinations of prefix, base, and suffix.
*/
public static ImmutableSet<String> combine(
@Nullable Set<String> prefixes, String base, @Nullable Set<String> suffixes) {
ImmutableSet<String> suffixedSet;
if (suffixes == null || suffixes.isEmpty()) {
suffixedSet = ImmutableSet.of(base);
} else {
ImmutableSet.Builder<String> suffixedBuilder = ImmutableSet.builder();
for (String suffix : suffixes) {
suffixedBuilder.add(base + suffix);
}
suffixedSet = suffixedBuilder.build();
}
if (prefixes == null || prefixes.isEmpty()) {
return suffixedSet;
} else {
ImmutableSet.Builder<String> builder = ImmutableSet.builder();
for (String prefix : prefixes) {
for (String suffix : suffixedSet) {
builder.add(prefix + suffix);
}
}
return builder.build();
}
}
/**
* Tries to find a file with a specific name in a search path.
*
* @param name file name to look for.
* @param searchPath directories to search.
* @return if found: the path to the file. if not found, Optional.empty().
*/
public static Optional<Path> getOptionalFile(String name, Iterable<Path> searchPath) {
return getOptionalFile(name, searchPath, EXISTS);
}
/**
* Tries to find a file with a specific name in a search path.
*
* @param name file name to look for.
* @param searchPath directories to search.
* @param filter additional check that discovered paths must pass to be eligible.
* @return if found: the path to the file. if not found, Optional.empty().
*/
public static Optional<Path> getOptionalFile(
String name, Iterable<Path> searchPath, Function<Path, Boolean> filter) {
return getOptionalFile(ImmutableSet.of(name), searchPath, filter);
}
/**
* Tries to find a file with one of a number of possible names in a search path.
*
* @param possibleNames file names to look for.
* @param searchPath directories to search.
* @return if found: the path to the file. if not found, Optional.empty().
*/
public static Optional<Path> getOptionalFile(
Set<String> possibleNames, Iterable<Path> searchPath) {
return getOptionalFile(possibleNames, searchPath, EXISTS);
}
/**
* Tries to find a file with one of a number of possible names in a search path.
*
* @param possibleNames file names to look for.
* @param searchPath directories to search.
* @param filter additional check that discovered paths must pass to be eligible.
* @return if found: the path to the file. if not found, Optional.empty().
*/
public static Optional<Path> getOptionalFile(
Set<String> possibleNames, Iterable<Path> searchPath, Function<Path, Boolean> filter) {
for (Path path : searchPath) {
for (String filename : possibleNames) {
Path resolved = path.resolve(filename);
if (filter.apply(resolved)) {
return Optional.of(resolved);
}
}
}
return Optional.empty();
}
/** Constructor hidden; there is no reason to instantiate this class. */
private FileFinder() {}
}