Adapters that go the other way, to java.io.

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/Util.java

@@ -82,7 +82,7 @@ public static int getDefaultPort(String protocol) {
     return -1;
   }
 
-  public static void checkOffsetAndCount(int arrayLength, int offset, int count) {
+  public static void checkOffsetAndCount(long arrayLength, long offset, long count) {
     if ((offset | count) < 0 || offset > arrayLength || arrayLength - offset < count) {
       throw new ArrayIndexOutOfBoundsException();
     }

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/bytes/OkBuffer.java

@@ -21,6 +21,8 @@
 import java.util.Collections;
 import java.util.List;
 
+import static com.squareup.okhttp.internal.Util.checkOffsetAndCount;
+
 /**
  * A collection of bytes in memory.
  *
@@ -147,7 +149,7 @@ public String readUtf8(int byteCount) {
   }
 
   private byte[] readBytes(int byteCount) {
-    checkByteCount(byteCount);
+    checkOffsetAndCount(this.byteCount, 0, byteCount);
 
     int offset = 0;
     byte[] result = new byte[byteCount];
@@ -301,7 +303,7 @@ Segment writableSegment(int minimumCapacity) {
     // yielding sink [51%, 91%, 30%] and source [62%, 82%].
 
     if (source == this) throw new IllegalArgumentException("source == this");
-    source.checkByteCount(byteCount);
+    checkOffsetAndCount(source.byteCount, 0, byteCount);
 
     while (byteCount > 0) {
       // Is a prefix of the source's head segment all that we need to move?
@@ -365,7 +367,6 @@ public long indexOf(byte b) throws IOException {
   }
 
   @Override public void flush(Deadline deadline) {
-    throw new UnsupportedOperationException("Cannot flush() an OkBuffer");
   }
 
   @Override public void close(Deadline deadline) {
@@ -400,15 +401,4 @@ List<Integer> segmentSizes() {
     }
     return new String(result);
   }
-
-  /** Throws if this has fewer bytes than {@code requested}. */
-  void checkByteCount(long requested) {
-    if (requested < 0) {
-      throw new IllegalArgumentException("requested < 0: " + requested);
-    }
-    if (requested > this.byteCount) {
-      throw new IllegalArgumentException(
-          String.format("requested %s > available %s", requested, this.byteCount));
-    }
-  }
 }

okhttp-protocols/src/main/java/com/squareup/okhttp/internal/bytes/OkBuffers.java

@@ -19,6 +19,8 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 
+import static com.squareup.okhttp.internal.Util.checkOffsetAndCount;
+
 public final class OkBuffers {
   private OkBuffers() {
   }
@@ -28,7 +30,7 @@ public static Sink sink(final OutputStream out) {
     return new Sink() {
       @Override public void write(OkBuffer source, long byteCount, Deadline deadline)
           throws IOException {
-        source.checkByteCount(byteCount);
+        checkOffsetAndCount(source.byteCount, 0, byteCount);
         while (byteCount > 0) {
           deadline.throwIfReached();
           Segment head = source.head;
@@ -60,6 +62,52 @@ public static Sink sink(final OutputStream out) {
     };
   }
 
+  /**
+   * Returns an output stream that writes to {@code sink}. This may buffer data
+   * by deferring writes.
+   */
+  public static OutputStream outputStream(final Sink sink) {
+    return new OutputStream() {
+      final OkBuffer buffer = new OkBuffer(); // Buffer at most one segment of data.
+
+      @Override public void write(int b) throws IOException {
+        buffer.writeByte((byte) b);
+        if (buffer.byteCount == Segment.SIZE) {
+          sink.write(buffer, buffer.byteCount, Deadline.NONE);
+        }
+      }
+
+      @Override public void write(byte[] data, int offset, int byteCount) throws IOException {
+        checkOffsetAndCount(data.length, offset, byteCount);
+        int limit = offset + byteCount;
+        while (offset < limit) {
+          Segment onlySegment = buffer.writableSegment(1);
+          int toCopy = Math.min(limit - offset, Segment.SIZE - onlySegment.limit);
+          System.arraycopy(data, offset, onlySegment.data, onlySegment.limit, toCopy);
+          offset += toCopy;
+          onlySegment.limit += toCopy;
+          buffer.byteCount += toCopy;
+          if (buffer.byteCount == Segment.SIZE) {
+            sink.write(buffer, buffer.byteCount, Deadline.NONE);
+          }
+        }
+      }
+
+      @Override public void flush() throws IOException {
+        sink.write(buffer, buffer.byteCount, Deadline.NONE);
+        sink.flush(Deadline.NONE);
+      }
+
+      @Override public void close() throws IOException {
+        sink.close(Deadline.NONE);
+      }
+
+      @Override public String toString() {
+        return "outputStream(" + sink + ")";
+      }
+    };
+  }
+
   /** Returns a source that reads from {@code in}. */
   public static Source source(final InputStream in) {
     return new Source() {
@@ -85,4 +133,57 @@ public static Source source(final InputStream in) {
       }
     };
   }
+
+  /**
+   * Returns an input stream that reads from {@code source}. This may buffer
+   * data by reading extra data eagerly.
+   */
+  public static InputStream inputStream(final Source source) {
+    return new InputStream() {
+      final OkBuffer buffer = new OkBuffer();
+
+      @Override public int read() throws IOException {
+        if (buffer.byteCount == 0) {
+          long count = source.read(buffer, Segment.SIZE, Deadline.NONE);
+          if (count == -1) return -1;
+        }
+        return buffer.readByte();
+      }
+
+      @Override public int read(byte[] data, int offset, int byteCount) throws IOException {
+        checkOffsetAndCount(data.length, offset, byteCount);
+
+        if (buffer.byteCount == 0) {
+          long count = source.read(buffer, Segment.SIZE, Deadline.NONE);
+          if (count == -1) return -1;
+        }
+
+        Segment head = buffer.head;
+        int toCopy = Math.min(byteCount, head.limit - head.pos);
+        System.arraycopy(head.data, head.pos, data, offset, toCopy);
+
+        head.pos += toCopy;
+        buffer.byteCount -= toCopy;
+
+        if (head.pos == head.limit) {
+          buffer.head = head.pop();
+          SegmentPool.INSTANCE.recycle(head);
+        }
+
+        return toCopy;
+      }
+
+      @Override public int available() throws IOException {
+        return (int) Math.min(buffer.byteCount, Integer.MAX_VALUE);
+      }
+
+      @Override public void close() throws IOException {
+        super.close();
+      }
+
+      @Override public String toString() {
+        return "inputStream(" + source + ")";
+      }
+    };
+  }
 }

okhttp-protocols/src/test/java/com/squareup/okhttp/internal/bytes/OkBufferTest.java

@@ -17,7 +17,9 @@
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.util.Arrays;
 import java.util.List;
 import org.junit.Test;
@@ -41,7 +43,7 @@ public final class OkBufferTest {
     try {
       buffer.readUtf8(1);
       fail();
-    } catch (IllegalArgumentException expected) {
+    } catch (ArrayIndexOutOfBoundsException expected) {
     }
   }
 
@@ -292,6 +294,26 @@ private List<Integer> moveBytesBetweenBuffers(String... contents) {
     assertEquals("a" + repeat('b', 9998) + "c", out.toString("UTF-8"));
   }
 
+  @Test public void outputStreamFromSink() throws Exception {
+    OkBuffer sink = new OkBuffer();
+    OutputStream out = OkBuffers.outputStream(sink);
+    out.write('a');
+    out.write(repeat('b', 9998).getBytes(UTF_8));
+    out.write('c');
+    out.flush();
+    assertEquals("a" + repeat('b', 9998) + "c", sink.readUtf8(10000));
+  }
+
+  @Test public void outputStreamFromSinkBounds() throws Exception {
+    OkBuffer sink = new OkBuffer();
+    OutputStream out = OkBuffers.outputStream(sink);
+    try {
+      out.write(new byte[100], 50, 51);
+      fail();
+    } catch (ArrayIndexOutOfBoundsException expected) {
+    }
+  }
+
   @Test public void sourceFromInputStream() throws Exception {
     InputStream in = new ByteArrayInputStream(
         ("a" + repeat('b', Segment.SIZE * 2) + "c").getBytes(UTF_8));
@@ -316,6 +338,62 @@ private List<Integer> moveBytesBetweenBuffers(String... contents) {
     assertEquals(-1, source.read(sink, 1, Deadline.NONE));
   }
 
+  @Test public void sourceFromInputStreamBounds() throws Exception {
+    Source source = OkBuffers.source(new ByteArrayInputStream(new byte[100]));
+    try {
+      source.read(new OkBuffer(), -1, Deadline.NONE);
+      fail();
+    } catch (IllegalArgumentException expected) {
+    }
+  }
+
+  @Test public void inputStreamFromSource() throws Exception {
+    OkBuffer source = new OkBuffer();
+    source.writeUtf8("a");
+    source.writeUtf8(repeat('b', Segment.SIZE));
+    source.writeUtf8("c");
+
+    InputStream in = OkBuffers.inputStream(source);
+    assertEquals(0, in.available());
+    assertEquals(Segment.SIZE + 2, source.byteCount());
+
+    // Reading one byte buffers a full segment.
+    assertEquals('a', in.read());
+    assertEquals(Segment.SIZE - 1, in.available());
+    assertEquals(2, source.byteCount());
+
+    // Reading as much as possible reads the rest of that buffered segment.
+    byte[] data = new byte[Segment.SIZE * 2];
+    assertEquals(Segment.SIZE - 1, in.read(data, 0, data.length));
+    assertEquals(repeat('b', Segment.SIZE - 1), new String(data, 0, Segment.SIZE - 1, UTF_8));
+    assertEquals(2, source.byteCount());
+
+    // Continuing to read buffers the next segment.
+    assertEquals('b', in.read());
+    assertEquals(1, in.available());
+    assertEquals(0, source.byteCount());
+
+    // Continuing to read reads from the buffer.
+    assertEquals('c', in.read());
+    assertEquals(0, in.available());
+    assertEquals(0, source.byteCount());
+
+    // Once we've exhausted the source, we're done.
+    assertEquals(-1, in.read());
+    assertEquals(0, source.byteCount());
+  }
+
+  @Test public void inputStreamFromSourceBounds() throws IOException {
+    OkBuffer source = new OkBuffer();
+    source.writeUtf8(repeat('a', 100));
+    InputStream in = OkBuffers.inputStream(source);
+    try {
+      in.read(new byte[100], 50, 51);
+      fail();
+    } catch (ArrayIndexOutOfBoundsException expected) {
+    }
+  }
+
   @Test public void writeBytes() throws Exception {
     OkBuffer data = new OkBuffer();
     data.writeByte(0xab);