Create NSDataBigString

Reviewed By: bnham

Differential Revision: D4559734

fbshipit-source-id: 6766093524ae79ed2a41285d33eb2207993a7d0e

React/CxxBridge/NSDataBigString.h

@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <Foundation/Foundation.h>
+
+#include <cxxreact/JSBigString.h>
+
+namespace facebook {
+namespace react {
+
+class NSDataBigString : public JSBigString {
+public:
+  // The NSData passed in must be be null-terminated.
+  NSDataBigString(NSData *data);
+
+  // The ASCII optimization is not enabled on iOS
+  bool isAscii() const override {
+    return false;
+  }
+
+  const char *c_str() const override {
+    return (const char *)[m_data bytes];
+  }
+
+  size_t size() const override {
+    return m_length;
+  }
+
+private:
+  NSData *m_data;
+  size_t m_length;
+};
+
+} }

React/CxxBridge/NSDataBigString.mm

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "NSDataBigString.h"
+
+namespace facebook {
+namespace react {
+
+static NSData *ensureNullTerminated(NSData *source)
+{
+  if (!source || source.length == 0) {
+    return nil;
+  }
+
+  NSUInteger sourceLength = source.length;
+  unsigned char lastByte;
+  [source getBytes:&lastByte range:NSMakeRange(sourceLength - 1, 1)];
+
+  // TODO: bundles from the packager should always include a NULL byte
+  // or we should we relax this requirement and only read as much from the
+  // buffer as length indicates
+  if (lastByte == '\0') {
+    return source;
+  } else {
+    NSMutableData *data = [source mutableCopy];
+    unsigned char nullByte = '\0';
+    [data appendBytes:&nullByte length:1];
+    return data;
+  }
+}
+
+NSDataBigString::NSDataBigString(NSData *data)
+{
+  m_length = [data length];
+  m_data = ensureNullTerminated(data);
+}
+
+} }

React/CxxBridge/RCTCxxBridge.mm

@@ -40,6 +40,7 @@
 #import <cxxreact/Platform.h>
 #import <jschelpers/Value.h>
 
+#import "NSDataBigString.h"
 #import "RCTMessageThread.h"
 #import "RCTNativeModule.h"
 #import "RCTObjcExecutor.h"
@@ -1183,10 +1184,7 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithBundleURL:(__unused NSURL *)bundleUR
         self->_reactInstance->loadUnbundle(std::move(ramBundle), std::move(scriptStr),
                                            [[url absoluteString] UTF8String]);
     } else if (self->_reactInstance) {
-      auto bigbuf = std::make_unique<JSBigBufferString>([script length]);
-      memcpy(bigbuf->data(), [script bytes], bigbuf->size());
-
-      self->_reactInstance->loadScriptFromString(std::move(bigbuf),
+      self->_reactInstance->loadScriptFromString(std::make_unique<NSDataBigString>(script),
                                                  [[url absoluteString] UTF8String]);
     }
   }];
@@ -1210,10 +1208,8 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithBundleURL:(__unused NSURL *)bundleUR
                                                [[url absoluteString] UTF8String]);
       }
     } else if (self->_reactInstance) {
-      auto bigbuf = std::make_unique<JSBigBufferString>([script length]);
-      memcpy(bigbuf->data(), [script bytes], bigbuf->size());
-
-      self->_reactInstance->loadScriptFromStringSync(std::move(bigbuf), [[url absoluteString] UTF8String]);
+      self->_reactInstance->loadScriptFromStringSync(std::make_unique<NSDataBigString>(script),
+                                                     [[url absoluteString] UTF8String]);
     } else {
       throw std::logic_error(
         "Attempt to call loadApplicationScriptSync: on uninitialized bridge");

ReactCommon/cxxreact/JSBigString.h

@@ -32,7 +32,11 @@ public:
   virtual ~JSBigString() {}
 
   virtual bool isAscii() const = 0;
+
+  // This needs to be a \0 terminated string
   virtual const char* c_str() const = 0;
+
+  // Length of the c_str without the NULL byte.
   virtual size_t size() const = 0;
 };