com.google.template.soy.error.PrettyErrorFactory.java Source code

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Here is the source code for com.google.template.soy.error.PrettyErrorFactory.java

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/*
 * Copyright 2015 Google 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.google.template.soy.error;

import com.google.common.base.Optional;
import com.google.common.base.Strings;
import com.google.template.soy.base.SourceLocation;

import java.io.IOException;

/**
 * Displays {@link SoyErrorKind}s in a useful way, with a snippet of Soy source
 * code containing the error and a caret pointing at the exact place where the error was found.
 *
 * @author brndn@google.com (Brendan Linn)
 */
public final class PrettyErrorFactory implements SoyError.Factory {

    private final SnippetFormatter snippetFormatter;

    public PrettyErrorFactory(SnippetFormatter snippetFormatter) {
        this.snippetFormatter = snippetFormatter;
    }

    @Override
    public SoyError create(SourceLocation location, SoyErrorKind kind, Object... args) {
        String message = kind.format(args);
        return SoyError.createError(location, message, getFormattedError(location, message));
    }

    private String getFormattedError(SourceLocation sourceLocation, String message) {
        StringBuilder builder = new StringBuilder();

        // Start by printing the actual text of the exception.
        builder.append("In file " + sourceLocation + ": " + message).append("\n");

        // Try to find a snippet of source code associated with the exception and print it.
        Optional<String> snippet;
        try {
            snippet = snippetFormatter.getSnippet(sourceLocation);
        } catch (IOException exception) {
            snippet = Optional.absent();
        }
        // TODO(user): this is a result of calling SoySyntaxException#createWithoutMetaInfo,
        // which occurs almost 100 times. Clean them up.
        if (snippet.isPresent()) {
            builder.append(snippet.get()).append("\n");
            // Print a caret below the error.
            // TODO(brndn): SourceLocation.beginColumn is occasionally -1. Review all SoySyntaxException
            // instantiations and ensure the SourceLocation is well-formed.
            int beginColumn = Math.max(sourceLocation.getBeginColumn(), 1);
            String caretLine = Strings.repeat(" ", beginColumn - 1) + "^";
            builder.append(caretLine).append("\n");
        }
        return builder.toString();
    }
}