@MavenArtifactSource can be gziped resources

common/src/main/java/org/treblereel/j2cl/processors/common/resources/ClientBundle.java

@@ -60,5 +60,7 @@ public interface ClientBundle {
     String path();
 
     String copyTo() default "<auto>";
+
+    boolean unzip() default false;
   }
 }

processor/src/main/java/org/treblereel/j2cl/processors/generator/resources/MavenArtifact.java

@@ -86,8 +86,8 @@ public String getRepositoryUrl() {
     return repositoryUrl;
   }
 
-  void copyResourceTo(String path, FileObject dst) {
-    mavenArtifactDownloader.copyResourceTo(path, dst);
+  void copyResourceTo(String path, FileObject dst, boolean unzip) {
+    mavenArtifactDownloader.copyResourceTo(path, dst, unzip);
   }
 
   @Override

processor/src/main/java/org/treblereel/j2cl/processors/generator/resources/MavenArtifactDownloader.java

@@ -19,9 +19,13 @@
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
+import java.io.PushbackInputStream;
 import java.util.Collections;
+import java.util.zip.GZIPInputStream;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 import javax.tools.FileObject;
@@ -58,19 +62,26 @@ class MavenArtifactDownloader {
     this.mavenArtifact = mavenArtifact;
   }
 
-  public void copyResourceTo(String path, FileObject dst) {
+  void copyResourceTo(String path, FileObject dst, boolean unzip) {
     if (artifact == null) {
       download();
     }
     try (ZipFile zipFile = new ZipFile(artifact.getFile())) {
       ZipEntry entry = zipFile.getEntry(path);
       if (entry != null) {
+        if (unzip && !checkIfZip(zipFile.getInputStream(entry))) {
+          throw new GenerationException("Resource with a path " + path + " isn't a GZIP");
+        }
         try (BufferedReader reader =
-                new BufferedReader(new InputStreamReader(zipFile.getInputStream(entry)));
+                new BufferedReader(
+                    new InputStreamReader(
+                        unzip
+                            ? new GZIPInputStream(zipFile.getInputStream(entry))
+                            : zipFile.getInputStream(entry)));
             BufferedWriter bufferedWriter =
                 new BufferedWriter(new OutputStreamWriter(dst.openOutputStream()))) {
 
-          char[] buffer = new char[1024]; // a buffer to hold chunks of characters
+          char[] buffer = new char[1024];
           int charsRead;
           while ((charsRead = reader.read(buffer)) != -1) {
             bufferedWriter.write(buffer, 0, charsRead);
@@ -85,6 +96,21 @@ public void copyResourceTo(String path, FileObject dst) {
     }
   }
 
+  private boolean checkIfZip(InputStream inputStream) {
+    if (!(inputStream instanceof PushbackInputStream)) {
+      inputStream = new PushbackInputStream(inputStream, 2);
+    }
+
+    byte[] signature = new byte[2];
+    try {
+      int bytesRead = inputStream.read(signature);
+      ((PushbackInputStream) inputStream).unread(signature, 0, bytesRead);
+      return bytesRead == 2 && signature[0] == (byte) 0x1f && signature[1] == (byte) 0x8b;
+    } catch (IOException e) {
+      throw new GenerationException(e);
+    }
+  }
+
   private void download() {
     RepositorySystem system = newRepositorySystem();
     RepositorySystemSession session = newSession(system);

processor/src/main/java/org/treblereel/j2cl/processors/generator/resources/MavenArtifactSourceProcessor.java

@@ -17,13 +17,8 @@
 package org.treblereel.j2cl.processors.generator.resources;
 
 import com.google.common.io.Files;
-import java.io.BufferedReader;
-import java.io.BufferedWriter;
 import java.io.File;
 import java.io.IOException;
-import java.io.InputStreamReader;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
@@ -103,8 +98,7 @@ private void copyResources(Map<MavenArtifact, Set<ExecutableElement>> mavenArtif
                       StandardLocation.CLASS_OUTPUT,
                       "", // no package
                       copyTo);
-          mavenArtifactSetEntry.getKey().copyResourceTo(path, resource);
-          // copy(is, os);
+          mavenArtifactSetEntry.getKey().copyResourceTo(path, resource, artifactSource.unzip());
         } catch (IOException e) {
           throw new RuntimeException(e);
         }
@@ -120,7 +114,7 @@ private void checkPath(String path, String type, ExecutableElement method) {
 
     if (!pattern.matcher(pkg).matches()) {
       throw new GenerationException(
-          "Wring " + type + " at " + method.getEnclosingElement() + "." + method.getSimpleName());
+          "Wrong " + type + " at " + method.getEnclosingElement() + "." + method.getSimpleName());
     }
   }
 
@@ -145,18 +139,4 @@ private void delete(File dir) {
       }
     }
   }
-
-  public void copy(InputStreamReader reader, OutputStream outStream) throws IOException {
-    try (BufferedReader bufferedReader = new BufferedReader(reader);
-        BufferedWriter bufferedWriter =
-            new BufferedWriter(new OutputStreamWriter(outStream, reader.getEncoding()))) {
-
-      char[] buffer = new char[1024]; // a buffer to hold chunks of characters
-      int charsRead;
-      while ((charsRead = bufferedReader.read(buffer)) != -1) {
-        bufferedWriter.write(buffer, 0, charsRead);
-      }
-      bufferedWriter.flush();
-    }
-  }
 }

tests/resources/src/test/java/org/treblereel/j2cl/processors/test/TextResourcesTest.java

@@ -104,4 +104,10 @@ public void testExternalResourceWebJarRename() {
     String content = readFileAsString("original_support.js");
     assertEquals(content, TextTestResourceImpl.INSTANCE.externalResourceWebJarRename().getText());
   }
+
+  @Test
+  public void testExternalResourceWebJarGZIP() {
+    String content = readFileAsString("bootstrap.min.js.back");
+    assertEquals(content, TextTestResourceImpl.INSTANCE.externalResourceWebJarGZIP().getText());
+  }
 }

tests/resources/src/test/java/org/treblereel/j2cl/processors/test/TextTestResource.java

@@ -77,4 +77,13 @@ interface TextTestResource extends ClientBundle {
       path = "META-INF/resources/webjars/jquery/3.7.1/src/css/support.js",
       copyTo = "org/test/support-old.js.back")
   TextResource externalResourceWebJarRenameDashInFile();
+
+  @MavenArtifactSource(
+      group = "org.webjars",
+      artifact = "bootstrap",
+      version = "3.4.1",
+      path = "META-INF/resources/webjars/bootstrap/3.4.1/js/bootstrap.min.js.gz",
+      copyTo = "org/test/bootstrap.min.js.back",
+      unzip = true)
+  TextResource externalResourceWebJarGZIP();
 }