Unify content-coding support: replace InputStreamFactory with symmetric Encoder/Decoder API, introduce IOFunction and ContentCodecRegistry, update DecompressingEntity and all tests accordingly.

arturobernalg · arturobernalg · commit 24ac6ca620f3 · 2025-07-04T08:36:56.000+02:00
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/CommonsCompressDecoderFactory.java b/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/CommonsCompressDecoderFactory.java
@@ -55,7 +55,7 @@
  */
 @Internal
 @Contract(threading = ThreadingBehavior.STATELESS)
-final class CommonsCompressDecoderFactory implements Decoder {
+final class CommonsCompressDecoderFactory {
 
     /**
      * Map of codings that need extra JARs → the fully‐qualified class we test for
@@ -71,27 +71,19 @@ final class CommonsCompressDecoderFactory implements Decoder {
         REQUIRED_CLASS_NAME = Collections.unmodifiableMap(m);
     }
 
-    private final String encoding;          // lower-case IANA token
-    private final CompressorStreamFactory factory = new CompressorStreamFactory();
-
-    CommonsCompressDecoderFactory(final String encoding) {
-        this.encoding = encoding.toLowerCase(Locale.ROOT);
-    }
-
-    public String getContentEncoding() {
-        return encoding;
-    }
-
     /**
-     * Lazily wraps the source stream in a Commons-Compress decoder.
+     * @return lazy decoder for the given IANA token (lower-case).
      */
-    @Override
-    public InputStream wrap(final InputStream source) throws IOException {
-        try {
-            return factory.createCompressorInputStream(encoding, source);
-        } catch (final CompressorException | LinkageError ex) {
-            throw new IOException("Unable to decode Content-Encoding '" + encoding + '\'', ex);
-        }
+    static IOFunction<InputStream, InputStream> decoder(final String token) {
+        final String enc = token.toLowerCase(Locale.ROOT);
+        final CompressorStreamFactory factory = new CompressorStreamFactory();
+        return in -> {
+            try {
+                return factory.createCompressorInputStream(enc, in);
+            } catch (final CompressorException | LinkageError ex) {
+                throw new IOException("Unable to decode Content-Encoding '" + enc + '\'', ex);
+            }
+        };
     }
 
     /**
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/ContentCodecRegistry.java b/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/ContentCodecRegistry.java
@@ -28,7 +28,6 @@
 package org.apache.hc.client5.http.entity.compress;
 
 import java.io.IOException;
-import java.io.InputStream;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.EnumMap;
@@ -59,20 +58,17 @@ public final class ContentCodecRegistry {
     private static final Map<ContentCoding, Codec> REGISTRY = build();
 
     private static Map<ContentCoding, Codec> build() {
-        final Map<ContentCoding, Codec> m =
-                new EnumMap<>(ContentCoding.class);
+        final Map<ContentCoding, Codec> m = new EnumMap<>(ContentCoding.class);
 
-        /* 1. Built-ins ------------------------------------------------- */
         m.put(ContentCoding.GZIP,
                 new Codec(
                         // encoder
                         org.apache.hc.client5.http.entity.GzipCompressingEntity::new,
-                        // decoder
-                        GZIPInputStream::new));
+                        ent -> new DecompressingEntity(ent, GZIPInputStream::new)));
         m.put(ContentCoding.DEFLATE,
                 new Codec(
                         org.apache.hc.client5.http.entity.DeflateCompressingEntity::new,
-                        DeflateInputStream::new));
+                        ent -> new DecompressingEntity(ent, DeflateInputStream::new)));
 
         /* 2. Commons-Compress extras ---------------------------------- */
         if (CommonsCompressSupport.isPresent()) {
@@ -88,8 +84,10 @@ private static Map<ContentCoding, Codec> build() {
                     ContentCoding.DEFLATE64)) {
 
                 if (CommonsCompressDecoderFactory.runtimeAvailable(c.token())) {
-                    m.put(c, new Codec(e -> new CommonsCompressingEntity(e, c.token()), new CommonsCompressDecoderFactory(c.token())
-                    ));
+                    m.put(c, new Codec(
+                            e -> new CommonsCompressingEntity(e, c.token()),
+                            ent -> new DecompressingEntity(ent,
+                                    CommonsCompressDecoderFactory.decoder(c.token()))));
                 }
             }
         }
@@ -98,35 +96,20 @@ private static Map<ContentCoding, Codec> build() {
         if (!m.containsKey(ContentCoding.BROTLI)
                 && CommonsCompressDecoderFactory.runtimeAvailable(ContentCoding.BROTLI.token())) {
             m.put(ContentCoding.BROTLI,
-                    Codec.decodeOnly(BrotliInputStream::new));
+                    Codec.decodeOnly(ent ->
+                            new DecompressingEntity(ent, BrotliInputStream::new)));
         }
 
         return Collections.unmodifiableMap(m);
     }
 
-
-    /**
-     * Returns the {@link Codec} (or {@code null}).
-     */
-    public static Codec codec(final ContentCoding coding) {
-        return REGISTRY.get(coding);
-    }
-
-    /**
-     * Convenient encoder helper – returns {@code null} if unsupported.
-     */
-    public static HttpEntity wrap(final ContentCoding coding,
-                                  final HttpEntity src) {
-        final Codec c = codec(coding);
+    public static HttpEntity wrap(final ContentCoding coding, final HttpEntity src) {
+        final Codec c = REGISTRY.get(coding);
         return c != null && c.encoder != null ? c.encoder.wrap(src) : null;
     }
 
-    /**
-     * Convenient decoder helper – returns {@code null} if unsupported.
-     */
-    public static InputStream unwrap(final ContentCoding coding,
-                                     final InputStream src) throws IOException {
-        final Codec c = codec(coding);
+    public static HttpEntity unwrap(final ContentCoding coding, final HttpEntity src) throws IOException {
+        final Codec c = REGISTRY.get(coding);
         return c != null && c.decoder != null ? c.decoder.wrap(src) : null;
     }
 
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/Decoder.java b/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/Decoder.java
@@ -28,33 +28,33 @@
 package org.apache.hc.client5.http.entity.compress;
 
 import java.io.IOException;
-import java.io.InputStream;
+
+import org.apache.hc.core5.http.HttpEntity;
 
 /**
- * Pull-side transformer that takes a compressed {@link InputStream} and
+ * Pull-side transformer that takes a compressed {@link HttpEntity} and
  * returns a lazily-decoded view of the same byte sequence.
  *
- * <p>Implementations <strong>must</strong> return a stream that honours the
- * usual {@code InputStream} contract and propagates {@link IOException}s
- * raised by the underlying transport.</p>
+ * <p>Implementations <strong>must</strong> return an entity whose
+ * {@code InputStream} honours the usual stream contract and propagates
+ * {@link IOException}s raised by the underlying transport.</p>
  *
  * @since 5.6
  */
 @FunctionalInterface
 public interface Decoder {
 
     /**
-     * Wraps the supplied source stream in a decoding stream that transparently
+     * Wraps the supplied source entity in a decoding entity that transparently
      * produces the uncompressed data.
      *
-     * @param src the source {@code InputStream} positioned at the start of the
+     * @param src the source {@code HttpEntity} positioned at the start of the
      *            encoded payload (never {@code null})
-     * @return a new, undecoded {@code InputStream}; the caller is responsible
-     * for closing it
-     * @throws IOException if the decoding stream cannot be created or an
+     * @return a new, undecoded {@code HttpEntity}; the caller is responsible
+     *         for consuming / closing its content stream
+     * @throws IOException if the decoding entity cannot be created or an
      *                     underlying I/O error occurs
      */
-    InputStream wrap(InputStream src) throws IOException;
+    HttpEntity wrap(HttpEntity src) throws IOException;
 }
 
-
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/DecompressingEntity.java b/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/DecompressingEntity.java
@@ -39,14 +39,15 @@
 public class DecompressingEntity extends HttpEntityWrapper {
 
     private static final int BUF_SIZE = 8 * 1024;   // 8 KiB buffer
-
-    private final Decoder decoder;
+    private final IOFunction<InputStream, InputStream> decoder;
     private final ReentrantLock lock = new ReentrantLock();
     private volatile InputStream cached;
 
-    public DecompressingEntity(final HttpEntity src, final Decoder decoder) {
+    public DecompressingEntity(
+            final HttpEntity src,
+            final IOFunction<InputStream, InputStream> decoder) {
         super(src);
-        this.decoder = Args.notNull(decoder, "Decoder");
+        this.decoder = Args.notNull(decoder, "Stream decoder");
     }
 
     /**
@@ -55,15 +56,15 @@ public DecompressingEntity(final HttpEntity src, final Decoder decoder) {
     @Override
     public InputStream getContent() throws IOException {
         if (!isStreaming()) {
-            return decoder.wrap(super.getContent());
+            return decoder.apply(super.getContent());
         }
 
         InputStream local = cached;
         if (local == null) {
             lock.lock();
             try {
                 if (cached == null) {
-                    cached = decoder.wrap(super.getContent());
+                    cached = decoder.apply(super.getContent());
                 }
                 local = cached;
             } finally {
@@ -81,6 +82,16 @@ public long getContentLength() {
         return -1;
     }
 
+    @Override
+    public boolean isRepeatable() {
+        return super.isRepeatable();
+    }
+
+    @Override
+    public boolean isStreaming() {
+        return super.isStreaming();
+    }
+
     /**
      * Streams the decoded bytes directly to {@code out}.
      */
@@ -95,14 +106,4 @@ public void writeTo(final OutputStream out) throws IOException {
             }
         }
     }
-
-    @Override
-    public boolean isRepeatable() {
-        return super.isRepeatable();
-    }
-
-    @Override
-    public boolean isStreaming() {
-        return super.isStreaming();
-    }
-}
+}
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/IOFunction.java b/httpclient5/src/main/java/org/apache/hc/client5/http/entity/compress/IOFunction.java
@@ -0,0 +1,58 @@
+/*
+ * ====================================================================
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ * ====================================================================
+ *
+ * This software consists of voluntary contributions made by many
+ * individuals on behalf of the Apache Software Foundation.  For more
+ * information on the Apache Software Foundation, please see
+ * <http://www.apache.org/>.
+ *
+ */
+
+package org.apache.hc.client5.http.entity.compress;
+
+import java.io.IOException;
+
+import org.conscrypt.Internal;
+
+/**
+ * Minimal equivalent of {@link java.util.function.Function} whose
+ * {@link #apply(Object)} method is allowed to throw {@link IOException}.
+ * <p>
+ * Used internally by the content-coding layer to pass lambdas that wrap /
+ * unwrap streams without forcing boiler-plate try/catch blocks.
+ * </p>
+ *
+ * @param <T> input type
+ * @param <R> result type
+ * @since 5.6
+ */
+@Internal
+@FunctionalInterface
+public interface IOFunction<T, R> {
+
+    /**
+     * Applies the transformation.
+     *
+     * @param value source value (never {@code null})
+     * @return transformed value
+     * @throws IOException if the transformation cannot be performed
+     */
+    R apply(T value) throws IOException;
+}
diff --git a/httpclient5/src/main/java/org/apache/hc/client5/http/impl/classic/ContentCompressionExec.java b/httpclient5/src/main/java/org/apache/hc/client5/http/impl/classic/ContentCompressionExec.java
@@ -40,7 +40,6 @@
 import org.apache.hc.client5.http.entity.compress.ContentCodecRegistry;
 import org.apache.hc.client5.http.entity.compress.ContentCoding;
 import org.apache.hc.client5.http.entity.compress.Decoder;
-import org.apache.hc.client5.http.entity.compress.DecompressingEntity;
 import org.apache.hc.client5.http.protocol.HttpClientContext;
 import org.apache.hc.core5.annotation.Contract;
 import org.apache.hc.core5.annotation.Internal;
@@ -149,14 +148,12 @@ public ClassicHttpResponse execute(
                     final String codecname = codec.getName().toLowerCase(Locale.ROOT);
                     final Decoder decoder = decoderRegistry.lookup(codecname);
                     if (decoder != null) {
-                        response.setEntity(new DecompressingEntity(response.getEntity(), decoder));
+                        response.setEntity(decoder.wrap(response.getEntity()));
                         response.removeHeaders(HttpHeaders.CONTENT_LENGTH);
                         response.removeHeaders(HttpHeaders.CONTENT_ENCODING);
                         response.removeHeaders(HttpHeaders.CONTENT_MD5);
-                    } else {
-                        if (!"identity".equals(codecname) && !ignoreUnknown) {
-                            throw new HttpException("Unsupported Content-Encoding: " + codec.getName());
-                        }
+                    } else if (!"identity".equals(codecname) && !ignoreUnknown) {
+                        throw new HttpException("Unsupported Content-Encoding: " + codec.getName());
                     }
                 }
             }
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestBrotli.java b/httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestBrotli.java
@@ -47,9 +47,9 @@ void testDecompressionWithBrotli() throws Exception {
 
         final byte[] bytes = new byte[] {33, 44, 0, 4, 116, 101, 115, 116, 32, 98, 114, 111, 116, 108, 105, 10, 3};
 
-        final HttpEntity entity = new org.apache.hc.client5.http.entity.compress.DecompressingEntity(
-                new ByteArrayEntity(bytes, null),
-                ContentCodecRegistry.decoder(ContentCoding.BROTLI));
+        final HttpEntity entity = ContentCodecRegistry.unwrap(
+                ContentCoding.BROTLI,
+                new ByteArrayEntity(bytes, null));
 
         Assertions.assertEquals("test brotli\n", EntityUtils.toString(entity));
     }
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestDeflate.java b/httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestDeflate.java
@@ -57,9 +57,9 @@ void testCompressDecompress() throws Exception {
         compresser.finish();
         final int len = compresser.deflate(compressed);
 
-        final HttpEntity entity = new org.apache.hc.client5.http.entity.compress.DecompressingEntity(
-                new ByteArrayEntity(compressed, 0, len, ContentType.APPLICATION_OCTET_STREAM),
-                ContentCodecRegistry.decoder(ContentCoding.DEFLATE));
+        final HttpEntity entity = ContentCodecRegistry
+                .decoder(ContentCoding.DEFLATE)
+                .wrap(new ByteArrayEntity(compressed, 0, len, ContentType.APPLICATION_OCTET_STREAM));
 
         Assertions.assertEquals(s, EntityUtils.toString(entity));
     }
@@ -78,9 +78,9 @@ void testEncodeThenDecode() throws Exception {
         final ByteArrayOutputStream buf = new ByteArrayOutputStream();
         deflated.writeTo(buf);
 
-        final HttpEntity decoded = new org.apache.hc.client5.http.entity.compress.DecompressingEntity(
-                new ByteArrayEntity(buf.toByteArray(), ContentType.APPLICATION_OCTET_STREAM),
-                ContentCodecRegistry.decoder(ContentCoding.DEFLATE));
+        final HttpEntity decoded = ContentCodecRegistry
+                .decoder(ContentCoding.DEFLATE)
+                .wrap(new ByteArrayEntity(buf.toByteArray(), ContentType.APPLICATION_OCTET_STREAM));
 
         Assertions.assertEquals(text, EntityUtils.toString(decoded, StandardCharsets.US_ASCII));
     }
diff --git a/httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestGZip.java b/httpclient5/src/test/java/org/apache/hc/client5/http/entity/TestGZip.java
