de.flapdoodle.guava.buildsupport.ExtractMarkdownFromCode.java Source code

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Here is the source code for de.flapdoodle.guava.buildsupport.ExtractMarkdownFromCode.java

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/**
 * Copyright (C) 2013
 *   Michael Mosmann <michael@mosmann.de>
 *
 * 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 de.flapdoodle.guava.buildsupport;

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

import com.google.common.base.Charsets;
import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.collect.Collections2;
import com.google.common.collect.Lists;
import com.google.common.io.Files;

public class ExtractMarkdownFromCode {

    public static void main(String[] args) {
        String sourceFileName = args[0];
        String destFileName = args[1];

        try {
            String markDown = extractMarkdown(sourceFileName);
            Files.write(markDown, new File(destFileName), Charsets.UTF_8);
        } catch (IOException e) {
            throw new RuntimeException("could not extract markdown", e);
        }
    }

    private static String extractMarkdown(String sourceFileName) throws IOException {
        List<String> lines = Files.readLines(new File(sourceFileName), Charsets.UTF_8);
        Collection<String> result = compactEmptyLines(surroundHeadlineWithEmptyLines(
                uncommentLineComment(uncommentThreeDots(shiftOneTabLeft(stripNonCodeLines(
                        freeHeader(startWithFirstHeader(resolveIncludes(sourceFileName, lines)))))))));
        StringBuilder sb = new StringBuilder();
        for (String line : result) {
            sb.append(line);
            sb.append("\n");
        }

        return sb.toString();
    }

    private static Collection<String> resolveIncludes(String sourceFileName, Collection<String> lines)
            throws IOException {
        List<String> ret = Lists.newArrayList();
        String includeTag = "// @include";

        for (String line : lines) {
            int includeDefIdx = line.indexOf(includeTag);
            if (includeDefIdx != -1) {
                String fileName = line.substring(includeDefIdx + includeTag.length()).trim();
                String basePath = sourceFileName.substring(0, sourceFileName.lastIndexOf('/') + 1);
                String includeFilename = basePath + fileName;
                List<String> includedLines = Files.readLines(new File(includeFilename), Charsets.UTF_8);
                Collection<String> shiftedLines = Collections2.transform(includedLines,
                        new Function<String, String>() {

                            @Override
                            public String apply(String input) {
                                return "\t\t" + input;
                            }
                        });
                ret.addAll(shiftedLines);
            } else {
                ret.add(line);
            }
        }
        return ret;
    }

    private static Collection<String> surroundHeadlineWithEmptyLines(Collection<String> lines) {
        List<String> ret = Lists.newArrayList();
        for (String line : lines) {
            if (isHeader(line)) {
                ret.add("");
                ret.add(line);
                ret.add("");
            } else {
                ret.add(line);
            }
        }
        return ret;
    }

    private static Collection<String> uncommentThreeDots(Collection<String> lines) {
        return Collections2.transform(lines, new Function<String, String>() {

            @Override
            public String apply(String input) {
                return input.replace("// ...", "...");
            }
        });
    }

    private static Collection<String> uncommentLineComment(Collection<String> lines) {
        return Collections2.transform(lines, new Function<String, String>() {

            @Override
            public String apply(String input) {
                if (input.startsWith("// ")) {
                    return input.substring(3);
                }
                return input;
            }
        });
    }

    private static Collection<String> compactEmptyLines(Collection<String> lines) {
        return Collections2.filter(Collections2.transform(lines, new Function<String, String>() {

            @Override
            public String apply(String input) {
                if (input.trim().isEmpty()) {
                    return "";
                }
                return input;
            }
        }), new Predicate<String>() {
            boolean lastOneWasEmpty = false;

            @Override
            public boolean apply(String input) {
                boolean addThisLine = true;

                if (input.isEmpty()) {
                    if (lastOneWasEmpty)
                        addThisLine = false;
                    lastOneWasEmpty = true;
                } else {
                    lastOneWasEmpty = false;
                }
                return addThisLine;
            }
        });
    }

    private static Collection<String> shiftOneTabLeft(Collection<String> lines) {
        return Collections2.transform(lines, new Function<String, String>() {

            @Override
            public String apply(String input) {
                if ((!input.isEmpty()) && (input.charAt(0) == '\t'))
                    return input.substring(1);
                return input;
            }
        });
    }

    private static Collection<String> stripNonCodeLines(Collection<String> lines) {
        return Collections2.filter(lines, new Predicate<String>() {

            boolean codeStarted = false;

            @Override
            public boolean apply(String input) {
                boolean includeCurrentLine = true;
                if (!codeStarted) {
                    if (input.contains("// ->")) {
                        codeStarted = true;
                        includeCurrentLine = false;
                    }
                } else {
                    if (input.contains("// <-")) {
                        codeStarted = false;
                        includeCurrentLine = false;
                    }
                }
                return (codeStarted && includeCurrentLine) | isHeader(input);
            }
        });
    }

    private static Collection<String> freeHeader(Collection<String> lines) {
        return Collections2.transform(lines, new Function<String, String>() {

            @Override
            public String apply(String input) {
                return input.replace("// ###", "###");
            }
        });
    }

    private static Collection<String> startWithFirstHeader(Collection<String> lines) {
        Collection<String> withFirstHeader = Collections2.filter(lines, new Predicate<String>() {

            boolean hit = false;

            @Override
            public boolean apply(String input) {
                hit = hit | isHeader(input);
                return hit;
            }

        });
        return withFirstHeader;
    }

    private static boolean isHeader(String input) {
        return input.contains("###");
    }
}