Add support for PSR-7 StreamInterface

Closes #10

composer.json

@@ -19,7 +19,8 @@
     "require": {
         "php": "^7.0",
         "ext-intl": "*",
-        "pcrov/unicode": "^0.1"
+        "pcrov/unicode": "^0.1",
+        "psr/http-message": "^1"
     },
     "require-dev": {
         "phpunit/phpunit": "^6.5",

src/InputStream/Psr7Stream.php

@@ -0,0 +1,35 @@
+<?php declare(strict_types=1);
+
+namespace pcrov\JsonReader\InputStream;
+
+use Psr\Http\Message\StreamInterface;
+
+final class Psr7Stream implements InputStream
+{
+    const CHUNK_SIZE = 8192;
+
+    private $stream;
+
+    /**
+     * @throws IOException if the given stream is not readable.
+     */
+    public function __construct(StreamInterface $stream)
+    {
+        if (!$stream->isReadable()) {
+            throw new IOException("Stream must be readable.");
+        }
+
+        $this->stream = $stream;
+    }
+
+    public function read()
+    {
+        $stream = $this->stream;
+
+        try {
+            return $stream->eof() ? null : $stream->read(self::CHUNK_SIZE);
+        } catch (\RuntimeException $e) {
+            return null;
+        }
+    }
+}

src/JsonReader.php

@@ -3,12 +3,14 @@
 namespace pcrov\JsonReader;
 
 use pcrov\JsonReader\InputStream\IOException;
+use pcrov\JsonReader\InputStream\Psr7Stream;
 use pcrov\JsonReader\InputStream\Stream;
 use pcrov\JsonReader\InputStream\Uri;
 use pcrov\JsonReader\InputStream\StringInput;
 use pcrov\JsonReader\Parser\JsonParser;
 use pcrov\JsonReader\Parser\Lexer;
 use pcrov\JsonReader\Parser\Parser;
+use Psr\Http\Message\StreamInterface;
 
 class JsonReader
 {
@@ -103,6 +105,15 @@ public function open(string $uri)
         $this->init(new JsonParser(new Lexer(new Uri($uri))));
     }
 
+    /**
+     * @return void
+     * @throws IOException if a given stream is not readable.
+     */
+    public function psr7Stream(StreamInterface $stream)
+    {
+        $this->init(new JsonParser(new Lexer(new Psr7Stream($stream))));
+    }
+
     /**
      * @param resource $stream Readable file stream resource.
      * @return void

test/InputStream/Psr7StreamTest.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace pcrov\JsonReader\InputStream;
+
+use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\StreamInterface;
+
+class Psr7StreamTest extends TestCase
+{
+    public function testReadReturnsString()
+    {
+        $psr7 = $this->createMock(StreamInterface::class);
+        $psr7->method("isReadable")->willReturn(true);
+        $psr7->method("eof")->willReturn(false);
+        $psr7->method("read")->willReturn("foo");
+
+        $this->assertSame("foo", (new Psr7Stream($psr7))->read());
+    }
+
+    public function testReadEofReturnsNull()
+    {
+        $psr7 = $this->createMock(StreamInterface::class);
+        $psr7->method("isReadable")->willReturn(true);
+        $psr7->method("eof")->willReturn(true);
+
+        $this->assertNull((new Psr7Stream($psr7))->read());
+    }
+
+    public function testRuntimeExceptionReturnsNull()
+    {
+        $psr7 = $this->createMock(StreamInterface::class);
+        $psr7->method("isReadable")->willReturn(true);
+        $psr7->method("eof")->willReturn(false);
+        $psr7->method("read")->willThrowException(new \RuntimeException());
+
+        $this->assertNull((new Psr7Stream($psr7))->read());
+    }
+
+    public function testUnreadableStreamThrows()
+    {
+        $this->expectException(IOException::class);
+        $this->expectExceptionMessage("Stream must be readable.");
+
+        $psr7 = $this->createMock(StreamInterface::class);
+        $psr7->method("isReadable")->willReturn(false);
+        new Psr7Stream($psr7);
+    }
+}

test/JsonReaderTest.php

@@ -4,6 +4,7 @@
 
 use pcrov\JsonReader\Parser\Parser;
 use PHPUnit\Framework\TestCase;
+use Psr\Http\Message\StreamInterface;
 
 class JsonReaderTest extends TestCase
 {
@@ -74,6 +75,18 @@ public function testOpen()
         while ($reader->read());
     }
 
+    public function testPsr7Stream()
+    {
+        $reader = $this->reader;
+        $psr7 = $this->createMock(StreamInterface::class);
+        $psr7->method("isReadable")->willReturn(true);
+        $reader->psr7Stream($psr7);
+        $this->assertSame(0, $reader->depth());
+        $this->assertSame(JsonReader::NONE, $reader->type());
+        $this->assertNull($reader->name());
+        $this->assertNull($reader->value());
+    }
+
     public function testStream()
     {
         $reader = $this->reader;