sdk-common/src/main/java/com/android/ide/common/res2/MergingException.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * 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.android.ide.common.res2;

import com.android.annotations.NonNull;
import com.android.annotations.Nullable;
import com.android.ide.common.blame.FilePosition;
import com.android.ide.common.blame.SourcePosition;
import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;

import org.xml.sax.SAXParseException;

import java.io.File;
import java.util.List;

/** Exception for errors during merging */
public class MergingException extends Exception {
    private String mMessage; // Keeping our own copy since parent prepends exception class name
    private List<FilePosition> mFilePositions = Lists.newArrayList();

    public MergingException(@NonNull String message, @Nullable Throwable cause) {
        super(message, cause);
        mMessage = message;
    }

    public MergingException(@NonNull String message) {
        this(message, null);
    }

    public MergingException(@NonNull Throwable cause) {
        this(cause.getLocalizedMessage(), cause);
    }

    /**
     *  Add the file if it hasn't already been included in the list of file positions.
     */
    public MergingException setFile(@NonNull File file) {
        for (FilePosition filePosition : mFilePositions) {
            if (filePosition.getSourceFile().equals(file)) {
                return this;
            }
        }
        addFile(file);
        return this;
    }

    public MergingException addFile(@NonNull File file) {
        mFilePositions.add(new FilePosition(file, SourcePosition.UNKNOWN));
        return this;
    }

    public MergingException addFileIfNonNull(@Nullable File file) {
        return (file != null) ? addFile(file) : this;
    }

    public MergingException addFilePosition(@NonNull FilePosition filePosition) {
        mFilePositions.add(filePosition);
        return this;
    }

    public MergingException addFilePosition(@NonNull File file, @NonNull SAXParseException exception) {
        int lineNumber = exception.getLineNumber();
        if (lineNumber != -1) {
            addFilePosition(new FilePosition(file, new SourcePosition(
                    exception.getLineNumber() - 1, exception.getColumnNumber() - 1, -1)));
        } else {
            addFile(file);
        }
        return this;
    }

    public MergingException setCause(@NonNull Throwable cause) {
        initCause(cause);
        return this;
    }

    /** Computes the error message to display for this error */
    @Override
    public String getMessage() {
        StringBuilder sb = new StringBuilder();
        sb.append(Joiner.on('\t').join(mFilePositions));

        if (sb.length() > 0) {
            sb.append(':').append(' ');

            // ALWAYS insert the string "Error:" between the path and the message.
            // This is done to make the error messages more simple to detect
            // (since a generic path: message pattern can match a lot of output, basically
            // any labeled output, and we don't want to do file existence checks on any random
            // string to the left of a colon.)
            if (!mMessage.startsWith("Error: ")) {
                sb.append("Error: ");
            }
        } else if (!mMessage.contains("Error: ")) {
            sb.append("Error: ");
        }

        String message = mMessage;

        // If the error message already starts with the path, strip it out.
        // This avoids redundant looking error messages you can end up with
        // like for example for permission denied errors where the error message
        // string itself contains the path as a prefix:
        //    /my/full/path: /my/full/path (Permission denied)
        if (mFilePositions.size() == 1) {
           String path = mFilePositions.get(0).getSourceFile().getAbsolutePath();
            if (path != null && message.startsWith(path)) {
                int stripStart = path.length();
                if (message.length() > stripStart && message.charAt(stripStart) == ':') {
                    stripStart++;
                }
                if (message.length() > stripStart && message.charAt(stripStart) == ' ') {
                    stripStart++;
                }
                message = message.substring(stripStart);
            }
        }

        sb.append(message);
        return sb.toString();
    }

    @Override
    public String toString() {
        return getMessage();
    }
}