fix: Content-Encoding: gzip along with Transfer-Encoding: chunked…

… sometimes terminates early (#1608)

#### The issue
When `GZIPInputStream` completes processing an individual member it will call `InputStream#available()`
to determine if there is more stream to try and process. If the call to `available()` returns 0
`GZIPInputStream` will determine it has processed the entirety of the underlying stream. This is
spurious, as `InputStream#available()` is allowed to return 0 if it would require blocking in order
for more bytes to be available. When `GZIPInputStream` is reading from a `Transfer-Encoding: chunked`
response, if the chunk boundary happens to align closely enough to the member boundary
`GZIPInputStream` won't consume the whole response.

#### The fix
Add new `OptimisticAvailabilityInputStream`, which provides an optimistic "estimate" of the number of
`available()` bytes in the underlying stream. When instantiating a `GZIPInputStream` for a response,
automatically decorate the provided `InputStream` with an `OptimisticAvailabilityInputStream`.

#### Verification
This scenario isn't unique to processing of chunked responses, and can be replicated reliably using
a `java.io.SequenceInputStream` with two underlying `java.io.ByteArrayInputStream`. See
GzipSupportTest.java for a reproduction.

The need for this class has been verified for the following JVMs:
* ```
  openjdk version "1.8.0_292"
  OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_292-b10)
  OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.292-b10, mixed mode)
  ```
* ```
  openjdk version "11.0.14.1" 2022-02-08
  OpenJDK Runtime Environment Temurin-11.0.14.1+1 (build 11.0.14.1+1)
  OpenJDK 64-Bit Server VM Temurin-11.0.14.1+1 (build 11.0.14.1+1, mixed mode)
  ```
* ```
  openjdk version "17" 2021-09-14
  OpenJDK Runtime Environment Temurin-17+35 (build 17+35)
  OpenJDK 64-Bit Server VM Temurin-17+35 (build 17+35, mixed mode, sharing)
  ```

google-http-client/src/main/java/com/google/api/client/http/GzipSupport.java

@@ -0,0 +1,90 @@
+package com.google.api.client.http;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.zip.GZIPInputStream;
+
+final class GzipSupport {
+
+  private GzipSupport() {}
+
+  static GZIPInputStream newGzipInputStream(InputStream in) throws IOException {
+    return new GZIPInputStream(new OptimisticAvailabilityInputStream(in));
+  }
+
+  /**
+   * When {@link GZIPInputStream} completes processing an individual member it will call {@link
+   * InputStream#available()} to determine if there is more stream to try and process. If the call
+   * to {@code available()} returns 0 {@code GZIPInputStream} will determine it has processed the
+   * entirety of the underlying stream. This is spurious, as {@link InputStream#available()} is
+   * allowed to return 0 if it would require blocking in order for more bytes to be available. When
+   * {@code GZIPInputStream} is reading from a {@code Transfer-Encoding: chunked} response, if the
+   * chunk boundary happens to align closely enough to the member boundary {@code GZIPInputStream}
+   * won't consume the whole response.
+   *
+   * <p>This class, provides an optimistic "estimate" (in actuality, a lie) of the number of {@code
+   * available()} bytes in the underlying stream. It does this by tracking the last number of bytes
+   * read. If the last number of bytes read is grater than -1, we return {@link Integer#MAX_VALUE}
+   * to any call of {@link #available()}.
+   *
+   * <p>We're breaking the contract of available() in that we're lying about how much data we have
+   * accessible without blocking, however in the case where we're weaving {@link GZIPInputStream}
+   * into response processing we already know there are going to be blocking calls to read before
+   * the stream is exhausted.
+   *
+   * <p>This scenario isn't unique to processing of chunked responses, and can be replicated
+   * reliably using a {@link java.io.SequenceInputStream} with two underlying {@link
+   * java.io.ByteArrayInputStream}. See the corresponding test class for a reproduction.
+   *
+   * <p>The need for this class has been verified for the following JVMs:
+   *
+   * <ol>
+   *   <li>
+   *       <pre>
+   * openjdk version "1.8.0_292"
+   * OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_292-b10)
+   * OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.292-b10, mixed mode)
+   *   </pre>
+   *   <li>
+   *       <pre>
+   * openjdk version "11.0.14.1" 2022-02-08
+   * OpenJDK Runtime Environment Temurin-11.0.14.1+1 (build 11.0.14.1+1)
+   * OpenJDK 64-Bit Server VM Temurin-11.0.14.1+1 (build 11.0.14.1+1, mixed mode)
+   *   </pre>
+   *   <li>
+   *       <pre>
+   * openjdk version "17" 2021-09-14
+   * OpenJDK Runtime Environment Temurin-17+35 (build 17+35)
+   * OpenJDK 64-Bit Server VM Temurin-17+35 (build 17+35, mixed mode, sharing)
+   *   </pre>
+   * </ol>
+   */
+  private static final class OptimisticAvailabilityInputStream extends FilterInputStream {
+    private int lastRead = 0;
+
+    OptimisticAvailabilityInputStream(InputStream delegate) {
+      super(delegate);
+    }
+
+    @Override
+    public int available() throws IOException {
+      return lastRead > -1 ? Integer.MAX_VALUE : 0;
+    }
+
+    @Override
+    public int read() throws IOException {
+      return lastRead = super.read();
+    }
+
+    @Override
+    public int read(byte[] b) throws IOException {
+      return lastRead = super.read(b);
+    }
+
+    @Override
+    public int read(byte[] b, int off, int len) throws IOException {
+      return lastRead = super.read(b, off, len);
+    }
+  }
+}

google-http-client/src/main/java/com/google/api/client/http/HttpResponse.java

@@ -30,7 +30,6 @@
 import java.util.Locale;
 import java.util.logging.Level;
 import java.util.logging.Logger;
-import java.util.zip.GZIPInputStream;
 
 /**
  * HTTP response.
@@ -362,7 +361,7 @@ public InputStream getContent() throws IOException {
               // GZIPInputStream.close() --> ConsumingInputStream.close() -->
               // exhaust(ConsumingInputStream)
               lowLevelResponseContent =
-                  new GZIPInputStream(new ConsumingInputStream(lowLevelResponseContent));
+                  GzipSupport.newGzipInputStream(new ConsumingInputStream(lowLevelResponseContent));
             }
           }
           // logging (wrap content with LoggingInputStream)

google-http-client/src/test/java/com/google/api/client/http/GzipSupportTest.java

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * 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 com.google.api.client.http;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.io.ByteStreams;
+import com.google.common.io.CountingInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.SequenceInputStream;
+import java.util.zip.GZIPInputStream;
+import org.junit.Test;
+
+public final class GzipSupportTest {
+
+  @SuppressWarnings("UnstableApiUsage") // CountingInputStream is @Beta
+  @Test
+  public void gzipInputStreamConsumesAllBytes() throws IOException {
+    byte[] data = new byte[] {(byte) 'a', (byte) 'b'};
+    // `echo -n a > a.txt && gzip -n9 a.txt`
+    byte[] member0 =
+        new byte[] {
+          0x1f,
+          (byte) 0x8b,
+          0x08,
+          0x00,
+          0x00,
+          0x00,
+          0x00,
+          0x00,
+          0x02,
+          0x03,
+          0x4b,
+          0x04,
+          0x00,
+          (byte) 0x43,
+          (byte) 0xbe,
+          (byte) 0xb7,
+          (byte) 0xe8,
+          0x01,
+          0x00,
+          0x00,
+          0x00
+        };
+    // `echo -n b > b.txt && gzip -n9 b.txt`
+    byte[] member1 =
+        new byte[] {
+          0x1f,
+          (byte) 0x8b,
+          0x08,
+          0x00,
+          0x00,
+          0x00,
+          0x00,
+          0x00,
+          0x02,
+          0x03,
+          0x4b,
+          0x02,
+          0x00,
+          (byte) 0xf9,
+          (byte) 0xef,
+          (byte) 0xbe,
+          (byte) 0x71,
+          0x01,
+          0x00,
+          0x00,
+          0x00
+        };
+    int totalZippedBytes = member0.length + member1.length;
+    try (InputStream s =
+            new SequenceInputStream(
+                new ByteArrayInputStream(member0), new ByteArrayInputStream(member1));
+        CountingInputStream countS = new CountingInputStream(s);
+        GZIPInputStream g = GzipSupport.newGzipInputStream(countS);
+        CountingInputStream countG = new CountingInputStream(g)) {
+      ByteArrayOutputStream baos = new ByteArrayOutputStream();
+      ByteStreams.copy(countG, baos);
+      assertThat(baos.toByteArray()).isEqualTo(data);
+      assertThat(countG.getCount()).isEqualTo(data.length);
+      assertThat(countS.getCount()).isEqualTo(totalZippedBytes);
+    }
+  }
+}