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// 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.syntax;
import com.google.common.hash.HashCode;
import com.google.devtools.build.lib.vfs.FileSystemUtils;
import com.google.devtools.build.lib.vfs.Path;
import java.io.IOException;
import java.io.InputStream;
/**
* An abstraction for reading input from a file or taking it as a pre-cooked
* char[] or String.
*/
public abstract class ParserInputSource {
protected ParserInputSource() {}
/**
* Returns the content of the input source.
*/
public abstract char [] getContent();
/**
* Returns the path of the input source. Note: Once constructed, this object
* will never re-read the content from path.
*/
public abstract Path getPath();
/**
* Create an input source instance by (eagerly) reading from the file at
* path. The file is assumed to be ISO-8859-1 encoded and smaller than
* 2 Gigs - these assumptions are reasonable for BUILD files, which is
* all we care about here.
*/
public static ParserInputSource create(Path path) throws IOException {
char[] content = FileSystemUtils.readContentAsLatin1(path);
if (path.getFileSize() > content.length) {
// This assertion is to help diagnose problems arising from the
// filesystem; see bugs and #859334 and #920195.
throw new IOException("Unexpected short read from file '" + path
+ "' (expected " + path.getFileSize() + ", got " + content.length + " bytes)");
}
return create(content, path);
}
/**
* Create an input source from the given content, and associate path with
* this source. Path will be used in error messages etc. but we will *never*
* attempt to read the content from path.
*/
public static ParserInputSource create(String content, Path path) {
return create(content.toCharArray(), path);
}
/**
* Create an input source from the given content, and associate path with
* this source. Path will be used in error messages etc. but we will *never*
* attempt to read the content from path.
*/
public static ParserInputSource create(final char[] content, final Path path) {
return new ParserInputSource() {
@Override
public char[] getContent() {
return content;
}
@Override
public Path getPath() {
return path;
}
};
}
/**
* Create an input source from the given input stream, and associate path
* with this source. 'path' will be used in error messages, etc, but will
* not (in general) be used to to read the content from path.
*
* (The exception is the case in which Python pre-processing is required; the
* path will be used to provide the input to the Python pre-processor.
* Arguably, we should just send the content as input to the subprocess
* instead of using the path, but it's not clear it's worth the effort.)
*/
public static ParserInputSource create(InputStream in, Path path) throws IOException {
try {
return create(new String(FileSystemUtils.readContentAsLatin1(in)), path);
} finally {
in.close();
}
}
/**
* Returns a hash code calculated from the string content of this file.
*/
public String contentHashCode() throws IOException {
return HashCode.fromBytes(getPath().getMD5Digest()).toString();
}
}
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