Change Decompressor to use more efficient inflate_init() context

Among others, this also supports error reporting when decompressing an
invalid data stream and fixes all known inconsistencies.

Author: clue

README.md

@@ -15,7 +15,6 @@ supporting compression and decompression of GZIP, ZLIB and raw DEFLATE formats.
 * [Usage](#usage)
     * [Compressor](#compressor)
     * [Decompressor](#decompressor)
-    * [Inconsistencies](#inconsistencies)
 * [Install](#install)
 * [Tests](#tests)
 * [License](#license)
@@ -162,17 +161,6 @@ $input->pipe($decompressor)->pipe($filterBadWords)->pipe($output);
 For more details, see ReactPHP's
 [`DuplexStreamInterface`](https://github.com/reactphp/stream#duplexstreaminterface).
 
-### Inconsistencies
-
-The stream compression filters are not exactly the most commonly used features of PHP.
-As such, we've spotted some inconsistencies (or *bugs*) in different PHP versions.
-These inconsistencies exist in the underlying PHP engines and there's little we can do about this in this library.
-
-* All PHP versions: Decompressing invalid data does not emit any data (and does not raise an error)
-
-Our test suite contains several test cases that exhibit these issues.
-If you feel some test case is missing or outdated, we're happy to accept PRs! :)
-
 ## Install
 
 The recommended way to install this library is [through Composer](https://getcomposer.org).

src/Decompressor.php

@@ -31,15 +31,49 @@
  * For more details, see ReactPHP's
  * [`DuplexStreamInterface`](https://github.com/reactphp/stream#duplexstreaminterface).
  */
-final class Decompressor extends ZlibFilterStream
+final class Decompressor extends TransformStream
 {
+    /** @var ?resource */
+    private $context;
+
     /**
      * @param int $encoding ZLIB_ENCODING_GZIP, ZLIB_ENCODING_RAW or ZLIB_ENCODING_DEFLATE
      */
     public function __construct($encoding)
     {
-        parent::__construct(
-            Filter\fun('zlib.inflate', array('window' => $encoding))
-        );
+        $context = @inflate_init($encoding);
+        if ($context === false) {
+            throw new \InvalidArgumentException('Unable to initialize decompressor' . strstr(error_get_last()['message'], ':'));
+        }
+
+        $this->context = $context;
+    }
+
+    protected function transformData($chunk)
+    {
+        $ret = @inflate_add($this->context, $chunk);
+        if ($ret === false) {
+            throw new \RuntimeException('Unable to decompress' . strstr(error_get_last()['message'], ':'));
+        }
+
+        if ($ret !== '') {
+            $this->forwardData($ret);
+        }
+    }
+
+    protected function transformEnd($chunk)
+    {
+        $ret = @inflate_add($this->context, $chunk, ZLIB_FINISH);
+        $this->context = null;
+
+        if ($ret === false) {
+            throw new \RuntimeException('Unable to decompress' . strstr(error_get_last()['message'], ':'));
+        }
+
+        if ($ret !== '') {
+            $this->forwardData($ret);
+        }
+
+        $this->forwardEnd();
     }
 }

tests/DecompressorTest.php

@@ -0,0 +1,14 @@
+<?php
+
+use Clue\React\Zlib\Decompressor;
+
+class DecompressorTest extends TestCase
+{
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testCtorThrowsForInvalidEncoding()
+    {
+        new Decompressor(0);
+    }
+}

tests/DeflateDecompressorTest.php

@@ -48,10 +48,16 @@ public function testInflateBig()
         $this->assertEquals($data, $buffered);
     }
 
-    public function testInflateInvalid()
+    public function testDecompressInvalidDataEmitsError()
     {
-        $this->markTestSkipped('Not supported by any PHP version (neither does reject invalid data)');
+        $this->decompressor->on('data', $this->expectCallableNever());
+        $this->decompressor->on('error', $this->expectCallableOnce());
 
+        $this->decompressor->write('invalid');
+    }
+
+    public function testDecompressInvalidOnEndEmitsError()
+    {
         $this->decompressor->on('data', $this->expectCallableNever());
         $this->decompressor->on('error', $this->expectCallableOnce());
 

tests/GzipDecompressorTest.php

@@ -48,10 +48,16 @@ public function testDecompressBig()
         $this->assertEquals($data, $buffered);
     }
 
-    public function testDecompressInvalid()
+    public function testDecompressInvalidDataEmitsError()
     {
-        $this->markTestSkipped('Not supported by any PHP version (neither does reject invalid data)');
+        $this->decompressor->on('data', $this->expectCallableNever());
+        $this->decompressor->on('error', $this->expectCallableOnce());
 
+        $this->decompressor->write('invalid');
+    }
+
+    public function testDecompressInvalidOnEndEmitsError()
+    {
         $this->decompressor->on('data', $this->expectCallableNever());
         $this->decompressor->on('error', $this->expectCallableOnce());
 

tests/ZlibDecompressorTest.php

@@ -48,10 +48,16 @@ public function testDecompressBig()
         $this->assertEquals($data, $buffered);
     }
 
-    public function testDecompressInvalid()
+    public function testDecompressInvalidDataEmitsError()
     {
-        $this->markTestSkipped('Not supported by any PHP version (neither does reject invalid data)');
+        $this->decompressor->on('data', $this->expectCallableNever());
+        $this->decompressor->on('error', $this->expectCallableOnce());
 
+        $this->decompressor->write('invalid');
+    }
+
+    public function testDecompressInvalidOnEndEmitsError()
+    {
         $this->decompressor->on('data', $this->expectCallableNever());
         $this->decompressor->on('error', $this->expectCallableOnce());