Refactoring, more abstraction

Signed-off-by: Minecon724 <git@m724.eu>

.idea/vcs.xml

@@ -2,6 +2,7 @@
 <project version="4">
   <component name="VcsDirectoryMappings">
     <mapping directory="$PROJECT_DIR$" vcs="Git" />
+    <mapping directory="$PROJECT_DIR$/example_workdir" vcs="Git" />
     <mapping directory="$PROJECT_DIR$/m724" vcs="Git" />
   </component>
 </project>

src/main/java/eu/m724/blog/BlogBuilder.java

@@ -6,17 +6,19 @@
 
 package eu.m724.blog;
 
+import eu.m724.blog.compress.CommonsCompressor;
+import eu.m724.blog.compress.CompressException;
 import eu.m724.blog.compress.FileCompressor;
 import eu.m724.blog.compress.NoSuchAlgorithmException;
 import eu.m724.blog.object.Article;
 import eu.m724.blog.object.Feed;
 import eu.m724.blog.object.RenderOptions;
 import eu.m724.blog.object.Site;
+import eu.m724.blog.server.Server;
 import eu.m724.blog.template.TemplateRenderer;
-import org.apache.commons.compress.compressors.CompressorException;
+import eu.m724.blog.vc.GitVersionControl;
+import eu.m724.blog.vc.VersionControl;
 import org.apache.commons.io.file.PathUtils;
-import org.eclipse.jgit.api.Git;
-import org.eclipse.jgit.lib.RepositoryBuilder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -29,18 +31,18 @@ import java.util.stream.Collectors;
 
 /**
  * The {@code BlogBuilder} class facilitates building a static blog by managing templates,
- * assets, articles, and rendering output files. It uses a Git repository as the
+ * assets, articles, and rendering output files. It uses a version control (Git etc.) repository as the
  * source for the blog's content and configuration.
  */
 public class BlogBuilder {
     private static final Logger LOGGER = LoggerFactory.getLogger(BlogBuilder.class);
 
-    private final Git git;
+    private final Site site;
+    private final RenderOptions renderOptions;
+    private final VersionControl versionControl;
     private final Path workingDirectory;
 
-    private Site site;
     private TemplateRenderer template;
-    private RenderOptions renderOptions;
     private Minifier minifier;
 
     private Path templateDirectory;
@@ -50,12 +52,14 @@ public class BlogBuilder {
     /**
      * Constructs a {@link BlogBuilder} instance using the provided Git repository.
      *
-     * @param git the Git repository to be used for the blog.
+     * @param versionControl the version control repository to be used for the blog.
      */
-    public BlogBuilder(Git git) {
-        this.git = git;
+    private BlogBuilder(Site site, RenderOptions renderOptions, Path workingDirectory, VersionControl versionControl) {
+        this.site = site;
+        this.renderOptions = renderOptions;
+        this.versionControl = versionControl;
 
-        this.workingDirectory = git.getRepository().getDirectory().toPath().getParent();
+        this.workingDirectory = workingDirectory;
         this.templateDirectory = workingDirectory.resolve("template");
         this.outputDirectory = workingDirectory.resolve("generated_out");
     }
@@ -64,19 +68,19 @@ public class BlogBuilder {
      * Creates a new {@link BlogBuilder} instance for the specified working directory.
      * The directory is expected to be a Git repository.
      *
-     * @param workingDirectory the root path of the blog, which must contain a Git repository.
+     * @param directory the root path of the blog, which must be a Git repository.
      * @return a {@link BlogBuilder} instance
      * @throws IOException if there is an error accessing the Git repository
      */
-    public static BlogBuilder fromPath(Path workingDirectory) throws IOException {
-        var repository = new RepositoryBuilder()
-                .setGitDir(workingDirectory.resolve(".git").toFile())
-                .build();
-        var git = new Git(repository);
+    public static BlogBuilder fromGitRepository(Path directory) throws IOException {
+        return BlogBuilder.fromDirectory(directory, new GitVersionControl(directory));
+    }
 
-        //
+    public static BlogBuilder fromDirectory(Path directory, VersionControl versionControl) throws IOException {
+        var site = Site.fromConfig(directory.resolve("site.yml"));
+        var renderOptions = RenderOptions.fromConfig(directory.resolve("render.yml"));
 
-        return new BlogBuilder(git);
+        return new BlogBuilder(site, renderOptions, directory, versionControl);
     }
 
     /**
@@ -130,14 +134,7 @@ public class BlogBuilder {
      * @throws IOException if an I/O error occurs
      */
     public void build() throws IOException {
-        LOGGER.debug("Loading site...");
-        if (site == null)
-            this.site = Site.fromConfig(workingDirectory.resolve("site.yml"));
-
-        if (renderOptions == null)
-            this.renderOptions = RenderOptions.fromConfig(workingDirectory.resolve("render.yml"));
-
-        if (this.site.minify()) {
+        if (renderOptions.minify()) {
             try {
                 this.minifier = new Minifier();
             } catch (NoClassDefFoundError e) {
@@ -193,8 +190,7 @@ public class BlogBuilder {
                     continue;
                 }
 
-                path = articleDirectory.relativize(path);
-                var article = Article.fromFile(git, path);
+                var article = Article.fromFile(versionControl, path);
 
                 if (article.draft() && !renderDrafts) {
                     LOGGER.info("[Article {}] Draft. Ignoring, because you didn't specify to render drafts.", path.getFileName());
@@ -202,7 +198,7 @@ public class BlogBuilder {
                 }
 
                 var render = template.renderArticle(article);
-                var outFile = outputDirectory.resolve("article").resolve(path);
+                var outFile = outputDirectory.resolve("article").resolve(path.getFileName());
 
                 try {
                     Files.createDirectory(outFile.getParent());
@@ -229,8 +225,9 @@ public class BlogBuilder {
         if (renderOptions.remapAssets()) {
             var assetHashes = CacheBuster.copyTree(userAssetsDir, outputUserAssetsDir);
 
+            // This looks weird, but it's necessary if we want to use a single map
             assetHashes.forEach((k, v) -> {
-                fileHashes.put("assets/" + k, v); // TODO this feels like a hack
+                fileHashes.put("assets/" + k, v);
             });
         } else {
             FileUtils.copyTree(userAssetsDir, outputUserAssetsDir);
@@ -239,8 +236,9 @@ public class BlogBuilder {
         if (renderOptions.remapTemplateStatic()) {
             var templateStaticHashes = CacheBuster.copyTree(templateStaticDir, outputTemplateStaticDir);
 
+            // This looks weird, but it's necessary if we want to use a single map
             templateStaticHashes.forEach((k, v) -> {
-                fileHashes.put("static/" + k, v); // TODO this feels like a hack
+                fileHashes.put("static/" + k, v);
             });
         } else {
             FileUtils.copyTree(templateStaticDir, outputTemplateStaticDir);
@@ -259,7 +257,7 @@ public class BlogBuilder {
 
         for (var algorithm : renderOptions.compress()) {
             try {
-                var compressor = new FileCompressor(algorithm);
+                var compressor = new CommonsCompressor(algorithm);
                 compressors.add(compressor);
             } catch (NoSuchAlgorithmException e) {
                 LOGGER.error("No such compression algorithm, ignoring: {}", e.getAlgorithm());
@@ -276,8 +274,8 @@ public class BlogBuilder {
             for (var path : tree) {
                 try {
                     compressor.compress(path);
-                } catch (CompressorException e) {
-                    LOGGER.error("Error compressing \"{}\" to \"{}\": {}", path, compressor.getAlgorithm(), e.getMessage());
+                } catch (CompressException e) {
+                    LOGGER.error("Error compressing \"{}\" to \"{}\": {}", path, compressor.getAlgorithmName(), e.getMessage());
                 }
             }
         }

src/main/java/eu/m724/blog/Main.java

@@ -38,7 +38,10 @@ public class Main {
 
         var start = System.nanoTime();
 
-        var builder = BlogBuilder.fromPath(workingDirectory)
+
+        LOGGER.debug("Loading site...");
+
+        var builder = BlogBuilder.fromGitRepository(workingDirectory)
                 .templateDirectory(templateDirectory)
                 .outputDirectory(outputDirectory)
                 .renderDrafts(renderDrafts);

src/main/java/eu/m724/blog/YamlLoader.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog;
+
+import org.snakeyaml.engine.v2.api.Load;
+import org.snakeyaml.engine.v2.api.LoadSettings;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Map;
+
+public class YamlLoader {
+    private static final Load LOAD = new Load(LoadSettings.builder().build());
+
+    public static Map<String, Object> loadMap(Path file) throws IOException {
+        try (var inputStream = Files.newInputStream(file)) {
+            return (Map<String, Object>) LOAD.loadFromInputStream(inputStream);
+        }
+    }
+}

src/main/java/eu/m724/blog/compress/CommonsCompressor.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog.compress;
+
+import org.apache.commons.compress.compressors.CompressorException;
+import org.apache.commons.compress.compressors.CompressorStreamFactory;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.file.FileAlreadyExistsException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+public class CommonsCompressor extends FileCompressor {
+    /**
+     * Constructs a {@link FileCompressor} instance using the provided algorithm.
+     *
+     * @param algorithm The algorithm, for valid names see {@link CompressorStreamFactory}
+     * @throws NoSuchAlgorithmException If that algorithm is unavailable or the name is invalid.
+     */
+    public CommonsCompressor(String algorithm) throws NoSuchAlgorithmException {
+        super(algorithm);
+
+        try {
+            var os = new CompressorStreamFactory().createCompressorOutputStream(algorithm, OutputStream.nullOutputStream());
+            os.close();
+        } catch (NoClassDefFoundError | CompressorException e) {
+            throw new NoSuchAlgorithmException(algorithm, e);
+        } catch (IOException e) {
+            throw new RuntimeException("Unexpected IOException closing test output stream", e);
+        }
+    }
+
+    @Override
+    public void compress(Path file) throws IOException, CompressException {
+        var destination = file.resolveSibling(file.getFileName() + "." + getAlgorithmName());
+        compress(file, destination);
+    }
+
+    @Override
+    public void compress(Path source, Path destination) throws IOException, CompressException {
+        if (Files.exists(destination))
+            throw new FileAlreadyExistsException(destination.toString());
+
+        try (
+                var outputStream = new CompressorStreamFactory()
+                        .createCompressorOutputStream(getAlgorithmName(), Files.newOutputStream(destination))
+        ) {
+            Files.copy(source, outputStream);
+        } catch (CompressorException e) {
+            throw new CompressException(e);
+        }
+    }
+}

src/main/java/eu/m724/blog/compress/CompressException.java

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog.compress;
+
+// TODO really runtime exception?
+public class CompressException extends RuntimeException {
+    public CompressException(Throwable cause) {
+        super(cause);
+    }
+}

src/main/java/eu/m724/blog/compress/FileCompressor.java

@@ -6,53 +6,20 @@
 
 package eu.m724.blog.compress;
 
-import org.apache.commons.compress.compressors.CompressorException;
-import org.apache.commons.compress.compressors.CompressorStreamFactory;
-
 import java.io.IOException;
-import java.io.OutputStream;
 import java.nio.file.*;
 
-public class FileCompressor {
-    private final String algorithm;
+public abstract class FileCompressor {
+    private final String algorithmName;
 
-    /**
-     * Constructs a {@link FileCompressor} instance using the provided algorithm.
-     *
-     * @param algorithm The algorithm, for valid names see {@link CompressorStreamFactory}
-     * @throws NoSuchAlgorithmException If that algorithm is unavailable or the name is invalid.
-     */
-    public FileCompressor(String algorithm) throws NoSuchAlgorithmException {
-        this.algorithm = algorithm;
-
-        try {
-            var os = new CompressorStreamFactory().createCompressorOutputStream(algorithm, OutputStream.nullOutputStream());
-            os.close();
-        } catch (NoClassDefFoundError | CompressorException e) {
-            throw new NoSuchAlgorithmException(algorithm, e);
-        } catch (IOException e) {
-            throw new RuntimeException("Unexpected IOException closing test output stream", e);
-        }
+    protected FileCompressor(String algorithmName) {
+        this.algorithmName = algorithmName;
     }
 
-    public void compress(Path source) throws IOException, CompressorException {
-        var destination = source.resolveSibling(source.getFileName() + "." + algorithm);
-        compress(source, destination);
+    public String getAlgorithmName() {
+        return algorithmName;
     }
 
-    public void compress(Path source, Path destination) throws IOException, CompressorException {
-        if (Files.exists(destination))
-            throw new FileAlreadyExistsException(destination.toString());
-        
-        try (
-                var outputStream = new CompressorStreamFactory()
-                        .createCompressorOutputStream(algorithm, Files.newOutputStream(destination))
-        ) {
-            Files.copy(source, outputStream);
-        }
-    }
-
-    public String getAlgorithm() {
-        return algorithm;
-    }
+    abstract public void compress(Path file) throws IOException, CompressException;
+    abstract public void compress(Path source, Path destination) throws IOException, CompressException;
 }

src/main/java/eu/m724/blog/object/Article.java

@@ -6,8 +6,8 @@
 
 package eu.m724.blog.object;
 
-import org.eclipse.jgit.api.Git;
-import org.eclipse.jgit.api.errors.GitAPIException;
+import eu.m724.blog.vc.VersionControl;
+import eu.m724.blog.vc.VersionControlException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -56,17 +56,16 @@ public record Article(
      * The method extracts metadata properties, content, and versioning information
      * based on the Git history of the file.
      *
-     * @param git the Git repository used to retrieve versioning and commit information
+     * @param versionControl the version control repository used to retrieve versioning and commit information
      * @param path the relative path to the file within the "articles" directory
      * @return a {@link Article} object populated with data extracted from the specified file
      * @throws IOException if an error occurs during file reading
      */
-    public static Article fromFile(Git git, Path path) throws IOException {
+    public static Article fromFile(VersionControl versionControl, Path path) throws IOException {
         /* read properties before filtering */
 
         var slug = path.getFileName().toString().split("\\.")[0];
-        path = Path.of("articles").resolve(path);
-        var lines = Files.readAllLines(git.getRepository().getDirectory().toPath().getParent().resolve(path));
+        var lines = Files.readAllLines(path);
 
         var properties = new HashMap<String, String>();
 
@@ -121,18 +120,18 @@ public record Article(
         ZonedDateTime modifiedAt = Instant.ofEpochMilli(0).atZone(ZoneOffset.UTC);
 
         try {
-            for (var commit : git.log().addPath(path.toString()).call()) {
-                createdBy = commit.getAuthorIdent().getName();
-                createdAt = Instant.ofEpochSecond(commit.getCommitTime()).atZone(ZoneOffset.UTC);
+            for (var change : versionControl.getChanges(path)) {
+                createdBy = change.author();
+                createdAt = change.time();
 
                 if (revisions++ == 0) {
                     modifiedBy = createdBy;
                     modifiedAt = createdAt;
                 }
             }
-        } catch (GitAPIException e) {
+        } catch (VersionControlException e) {
             draft = true;
-            LOGGER.warn("[Article {}] Draft because of a Git exception: {}", slug, e.getMessage());
+            LOGGER.warn("[Article {}] Draft because of a VC exception: {}", slug, e.getMessage());
         }
 
         return new Article(slug, title, summary, draft, revisions, createdBy, createdAt, modifiedBy, modifiedAt, custom, content);

src/main/java/eu/m724/blog/object/RenderOptions.java

@@ -6,41 +6,61 @@
 
 package eu.m724.blog.object;
 
-import org.snakeyaml.engine.v2.api.Load;
-import org.snakeyaml.engine.v2.api.LoadSettings;
+import eu.m724.blog.YamlLoader;
 
 import java.io.IOException;
-import java.nio.file.Files;
 import java.nio.file.Path;
-import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
 
+/**
+ * Options that are relevant to rendering, not about the {@link Site}.
+ *
+ * @param compress list of compression algorithms to compress output
+ * @param remapAssets whether to remap user assets, add a unique hash to the file name to bypass cache
+ * @param remapTemplateStatic whether to remap template static assets, add a unique hash to the file name to bypass cache
+ * @param minify whether to minify output
+ */
 public record RenderOptions(
         List<String> compress, // TODO rename?
 
+        boolean remapAssets,
         boolean remapTemplateStatic,
-        boolean remapAssets
+
+        boolean minify
 ) {
+    private static final RenderOptions DEFAULT = new RenderOptions(
+            List.of("gz", "zstd"),
+            false,
+            true,
+            true
+    );
+
     /**
-     * Creates a {@link Site} object by reading and parsing the configuration file at the specified path.<br>
+     * Creates a {@link Site} object by reading and parsing the configuration file at the specified file.<br>
      * The configuration file must be a JSON file.
      *
-     * @param path the path to the configuration file
+     * @param file the file to the configuration file
      * @return a {@link Site} object initialized with the data from the configuration file
      * @throws IOException if an error occurs during file reading
      */
-    public static RenderOptions fromConfig(Path path) throws IOException {
-        var load = new Load(LoadSettings.builder().build());
-        var yaml = (Map<String, Object>) load.loadFromInputStream(Files.newInputStream(path));
+    public static RenderOptions fromConfig(Path file) throws IOException {
+        var yaml = YamlLoader.loadMap(file);
+
+        /* ---- */
+
+        List<String> compress = (List<String>) yaml.getOrDefault("compress", DEFAULT.compress());
 
-        List<String> compress = (List<String>) yaml.getOrDefault("compress", new ArrayList<>());
-        boolean remapTemplateStatic = (boolean) yaml.getOrDefault("remapTemplateStatic", true);
         // assets are not remapped by default, because they might be hotlinked
-        boolean remapAssets = (boolean) yaml.getOrDefault("remapAssets", false);
+        boolean remapAssets = (boolean) yaml.getOrDefault("remapAssets", DEFAULT.remapAssets());
+
+        boolean remapTemplateStatic = (boolean) yaml.getOrDefault("remapTemplateStatic", DEFAULT.remapTemplateStatic());
+
+        var minify = (boolean) yaml.getOrDefault("minify", DEFAULT.minify());
+
+        /* ---- */
 
         return new RenderOptions(
-                compress, remapTemplateStatic, remapAssets
+                compress, remapTemplateStatic, remapAssets, minify
         );
     }
 }

src/main/java/eu/m724/blog/object/Site.java

@@ -6,11 +6,9 @@
 
 package eu.m724.blog.object;
 
-import org.snakeyaml.engine.v2.api.Load;
-import org.snakeyaml.engine.v2.api.LoadSettings;
+import eu.m724.blog.YamlLoader;
 
 import java.io.IOException;
-import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Map;
 
@@ -21,7 +19,6 @@ import java.util.Map;
  * @param baseUrl the base URL of the site
  * @param directory The directory that the site is installed into. Like "https://example.com/blog" turns to "/blog"
  * @param templateArticles whether to parse articles with Pebble templating
- * @param minify whether to minify HTML, CSS, JS, etc.
  * @param custom a map of additional custom properties
  */
 public record Site(
@@ -31,28 +28,33 @@ public record Site(
         String directory,
 
         boolean templateArticles,
-        boolean minify,
 
         Map<String, Object> custom
 ) {
+    private static final Site DEFAULT = new Site(
+            "Misconfigured blog",
+            "/",
+            "/",
+            false,
+            Map.of()
+    );
+
     /**
      * Creates a {@link Site} object by reading and parsing the configuration file at the specified path.<br>
      * The configuration file must be a JSON file.
      *
-     * @param path the path to the configuration file
+     * @param file the path to the configuration file
      * @return a {@link Site} object initialized with the data from the configuration file
      * @throws IOException if an error occurs during file reading
      */
-    public static Site fromConfig(Path path) throws IOException {
-        var load = new Load(LoadSettings.builder().build());
-        var yaml = (Map<String, Object>) load.loadFromInputStream(Files.newInputStream(path));
+    public static Site fromConfig(Path file) throws IOException {
+        var yaml = YamlLoader.loadMap(file);
 
-        String name = (String) yaml.get("name");
-        String baseUrl = (String) yaml.getOrDefault("baseUrl", "/");
-        var templateArticles = (boolean) yaml.getOrDefault("templateArticles", false);
-        var minify = (boolean) yaml.getOrDefault("minify", true);
+        String name = (String) yaml.getOrDefault("name", DEFAULT.name());
+        String baseUrl = (String) yaml.getOrDefault("baseUrl", DEFAULT.baseUrl());
+        var templateArticles = (boolean) yaml.getOrDefault("templateArticles", DEFAULT.templateArticles());
 
-        String directory = "/";
+        String directory = DEFAULT.directory();
         if (baseUrl != null) {
             var temp = baseUrl.substring(baseUrl.indexOf(':') + 3);
             var slashIndex = temp.indexOf('/');
@@ -62,7 +64,7 @@ public record Site(
         }
 
         return new Site(
-                name, baseUrl, directory, templateArticles, minify, yaml
+                name, baseUrl, directory, templateArticles, yaml
         );
     }
 }

src/main/java/eu/m724/blog/server/Server.java

@@ -4,7 +4,7 @@
  * in the project root for the full license text.
  */
 
-package eu.m724.blog;
+package eu.m724.blog.server;
 
 import com.sun.net.httpserver.HttpServer;
 import com.sun.net.httpserver.SimpleFileServer;

src/main/java/eu/m724/blog/vc/Change.java

@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog.vc;
+
+import java.time.ZonedDateTime;
+
+public record Change(
+     String author,
+     ZonedDateTime time
+) { }

src/main/java/eu/m724/blog/vc/GitVersionControl.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog.vc;
+
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.lib.RepositoryBuilder;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.time.Instant;
+import java.time.ZoneOffset;
+import java.util.ArrayList;
+import java.util.List;
+
+public class GitVersionControl implements VersionControl {
+    private final Git git;
+    private final Path directory;
+
+    public GitVersionControl(Path directory) throws IOException {
+        this.directory = directory;
+
+        var repository = new RepositoryBuilder()
+                .setGitDir(directory.resolve(".git").toFile())
+                .build();
+
+        this.git = new Git(repository);
+    }
+
+    @Override
+    public List<Change> getChanges(Path path) throws VersionControlException {
+        path = path.normalize();
+        if (path.startsWith(directory)) {
+            path = directory.relativize(path);
+        }
+
+        var changes = new ArrayList<Change>();
+
+        try {
+            for (var commit : git.log().addPath(path.toString()).call()) {
+                var author = commit.getAuthorIdent().getName();
+                var time = Instant.ofEpochSecond(commit.getCommitTime()).atZone(ZoneOffset.UTC);
+
+                changes.add(new Change(author, time));
+            }
+        } catch (GitAPIException e) {
+            throw new VersionControlException(e);
+        }
+
+        return changes;
+    }
+}

src/main/java/eu/m724/blog/vc/VersionControl.java

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog.vc;
+
+import java.nio.file.Path;
+import java.util.List;
+
+public interface VersionControl {
+    List<Change> getChanges(Path path) throws VersionControlException;
+}
+

src/main/java/eu/m724/blog/vc/VersionControlException.java

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2025  blog-software-java developers
+ * blog-software-java is licensed under the GNU General Public License. See the LICENSE.md file
+ * in the project root for the full license text.
+ */
+
+package eu.m724.blog.vc;
+
+// TODO runtime exception really?
+public class VersionControlException extends RuntimeException {
+    public VersionControlException(Throwable cause) {
+        // TODO maybe I need to raise message here too
+        super(cause);
+    }
+}