Initial checkin of gRPC to third_party/

third_party/grpc/src/objective-c/GRPCClient/private/NSData+GRPC.m

+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#import "NSData+GRPC.h"
+
+#include <grpc/byte_buffer.h>
+#include <grpc/byte_buffer_reader.h>
+#include <string.h>
+
+// TODO(jcanizales): Move these two incantations to the C library.
+
+static void CopyByteBufferToCharArray(grpc_byte_buffer *buffer, char *array) {
+  size_t offset = 0;
+  grpc_byte_buffer_reader reader;
+  grpc_byte_buffer_reader_init(&reader, buffer);
+  gpr_slice next;
+  while (grpc_byte_buffer_reader_next(&reader, &next) != 0){
+    memcpy(array + offset, GPR_SLICE_START_PTR(next),
+           (size_t)GPR_SLICE_LENGTH(next));
+    offset += GPR_SLICE_LENGTH(next);
+    gpr_slice_unref(next);
+  }
+}
+
+static grpc_byte_buffer *CopyCharArrayToNewByteBuffer(const char *array,
+                                                      size_t length) {
+  gpr_slice slice = gpr_slice_from_copied_buffer(array, length);
+  grpc_byte_buffer *buffer = grpc_raw_byte_buffer_create(&slice, 1);
+  gpr_slice_unref(slice);
+  return buffer;
+}
+
+@implementation NSData (GRPC)
++ (instancetype)grpc_dataWithByteBuffer:(grpc_byte_buffer *)buffer {
+  if (buffer == NULL) {
+    return nil;
+  }
+  NSUInteger length = grpc_byte_buffer_length(buffer);
+  char *array = malloc(length * sizeof(*array));
+  if (!array) {
+    // TODO(jcanizales): grpc_byte_buffer is reference-counted, so we can
+    // prevent this memory problem by implementing a subclass of NSData
+    // that wraps the grpc_byte_buffer. Then enumerateByteRangesUsingBlock:
+    // can be implemented using a grpc_byte_buffer_reader.
+    return nil;
+  }
+  CopyByteBufferToCharArray(buffer, array);
+  return [self dataWithBytesNoCopy:array length:length freeWhenDone:YES];
+}
+
+- (grpc_byte_buffer *)grpc_byteBuffer {
+  // Some implementations of NSData, as well as grpc_byte_buffer, support O(1)
+  // appending of byte arrays by not using internally a single contiguous memory
+  // block for representation.
+  // The following implementation is thus not optimal, sometimes requiring two
+  // copies (one by self.bytes and another by gpr_slice_from_copied_buffer).
+  // If it turns out to be an issue, we can use enumerateByteRangesUsingblock:
+  // to create an array of gpr_slice objects to pass to grpc_raw_byte_buffer_create.
+  // That would make it do exactly one copy, always.
+  return CopyCharArrayToNewByteBuffer((const char *)self.bytes, (size_t)self.length);
+}
+@end