PluginInstaller returns now PendingPluginInstallation, to abort the installation before restart

scm-webapp/src/main/java/sonia/scm/plugin/PendingPluginInstallation.java

@@ -0,0 +1,31 @@
+package sonia.scm.plugin;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+
+class PendingPluginInstallation {
+
+  private static final Logger LOG = LoggerFactory.getLogger(PendingPluginInstallation.class);
+
+  private final AvailablePlugin plugin;
+  private final File file;
+
+  PendingPluginInstallation(AvailablePlugin plugin, File file) {
+    this.plugin = plugin;
+    this.file = file;
+  }
+
+  public AvailablePlugin getPlugin() {
+    return plugin;
+  }
+
+  void cancel() {
+    String name = plugin.getDescriptor().getInformation().getName();
+    LOG.info("cancel installation of plugin {}", name);
+    if (!file.delete()) {
+      throw new PluginFailedToCancelInstallationException("failed to cancel installation of plugin " + name);
+    }
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/PluginFailedToCancelInstallationException.java

@@ -0,0 +1,7 @@
+package sonia.scm.plugin;
+
+public class PluginFailedToCancelInstallationException extends RuntimeException {
+  public PluginFailedToCancelInstallationException(String message) {
+    super(message);
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/PluginInstaller.java

@@ -1,7 +1,5 @@
 package sonia.scm.plugin;
 
-import com.google.common.base.Throwables;
-import com.google.common.hash.HashFunction;
 import com.google.common.hash.Hashing;
 import com.google.common.io.ByteStreams;
 import com.google.common.io.Files;
@@ -28,12 +26,16 @@ class PluginInstaller {
     this.client = client;
   }
 
-  public void install(AvailablePlugin plugin) {
+  public PendingPluginInstallation install(AvailablePlugin plugin) {
     File file = createFile(plugin);
     try (InputStream input = download(plugin); OutputStream output = new FileOutputStream(file)) {
       ByteStreams.copy(input, output);
 
       verifyChecksum(plugin, file);
+
+      // TODO clean up in case of error
+
+      return new PendingPluginInstallation(plugin, file);
     } catch (IOException ex) {
       throw new PluginDownloadException("failed to install plugin", ex);
     }

scm-webapp/src/test/java/sonia/scm/plugin/PendingPluginInstallationTest.java

@@ -0,0 +1,46 @@
+package sonia.scm.plugin;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junitpioneer.jupiter.TempDirectory;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.Mockito.when;
+
+@ExtendWith({MockitoExtension.class, TempDirectory.class})
+class PendingPluginInstallationTest {
+
+  @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+  private AvailablePlugin plugin;
+
+  @Test
+  void shouldDeleteFileOnCancel(@TempDirectory.TempDir Path directory) throws IOException {
+    Path file = directory.resolve("file");
+    Files.write(file, "42".getBytes());
+
+    when(plugin.getDescriptor().getInformation().getName()).thenReturn("scm-awesome-plugin");
+
+    PendingPluginInstallation installation = new PendingPluginInstallation(plugin, file.toFile());
+    installation.cancel();
+
+    assertThat(file).doesNotExist();
+  }
+
+  @Test
+  void shouldThrowExceptionIfCancelFailed(@TempDirectory.TempDir Path directory) {
+    Path file = directory.resolve("file");
+    when(plugin.getDescriptor().getInformation().getName()).thenReturn("scm-awesome-plugin");
+
+    PendingPluginInstallation installation = new PendingPluginInstallation(plugin, file.toFile());
+    assertThrows(PluginFailedToCancelInstallationException.class, installation::cancel);
+  }
+
+}

scm-webapp/src/test/java/sonia/scm/plugin/PluginInstallerTest.java

@@ -51,6 +51,17 @@ class PluginInstallerTest {
     assertThat(directory.resolve("plugins").resolve("scm-git-plugin.smp")).hasContent("42");
   }
 
+  @Test
+  void shouldReturnPendingPluginInstallation() throws IOException {
+    mockContent("42");
+    AvailablePlugin gitPlugin = createGitPlugin();
+
+    PendingPluginInstallation pending = installer.install(gitPlugin);
+
+    assertThat(pending).isNotNull();
+    assertThat(pending.getPlugin()).isSameAs(gitPlugin);
+  }
+
   private void mockContent(String content) throws IOException {
     when(client.get("https://download.hitchhiker.com").request().contentAsStream())
       .thenReturn(new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8)));