Don't silently ignore RNG failures when creating strings / numbers.

webrtc/base/helpers.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_BASE_HELPERS_H_
 #define WEBRTC_BASE_HELPERS_H_
 
 #include <string>
 #include "webrtc/base/basictypes.h"
 
 namespace rtc {
 
 // For testing, we can return predictable data.
 void SetRandomTestMode(bool test);
 
 // Initializes the RNG, and seeds it with the specified entropy.
 bool InitRandom(int seed);
 bool InitRandom(const char* seed, size_t len);
 
 // Generates a (cryptographically) random string of the given length.
 // We generate base64 values so that they will be printable.
-// WARNING: could silently fail. Use the version below instead.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 std::string CreateRandomString(size_t length);
 
 // Generates a (cryptographically) random string of the given length.
 // We generate base64 values so that they will be printable.
 // Return false if the random number generator failed.
 bool CreateRandomString(size_t length, std::string* str);
 
 // Generates a (cryptographically) random string of the given length,
 // with characters from the given table. Return false if the random
 // number generator failed.
 bool CreateRandomString(size_t length, const std::string& table,
                         std::string* str);
 
 // Generates a (cryptographically) random UUID version 4 string.
+// WARNING: will abort() if the RNG fails! Use the version below instead.

[mattdr-at-webrtc.org, 2016/07/01 23:57:39]

Suggest removing these warnings. The RNG will almost never fail, and when it
does something is seriously wrong and the app is probably on its way out anyway.
It's probably not worth it for callers to even consider changing their code.

[joachim, 2016/07/02 00:12:01]

Done.

 std::string CreateRandomUuid();
 
+// Generates a (cryptographically) random UUID version 4 string.
+bool CreateRandomUuid(std::string* uuid);

[mattdr-at-webrtc.org, 2016/07/01 23:57:39]

Likewise, no need to increase the surface area by adding another verison of each
function. The extra complexity adds essentially no value.

[joachim, 2016/07/02 00:12:01]

Done.

+
 // Generates a random id.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 uint32_t CreateRandomId();
 
+// Generates a random id.
+bool CreateRandomId(uint32_t* id);
+
 // Generates a 64 bit random id.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 uint64_t CreateRandomId64();
 
+// Generates a 64 bit random id.
+bool CreateRandomId64(uint64_t* id);
+
 // Generates a random id > 0.
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 uint32_t CreateRandomNonZeroId();
 
+// Generates a random id > 0.
+bool CreateRandomNonZeroId(uint32_t* id);
+
 // Generates a random double between 0.0 (inclusive) and 1.0 (exclusive).
+// WARNING: will abort() if the RNG fails! Use the version below instead.
 double CreateRandomDouble();
 
+// Generates a random double between 0.0 (inclusive) and 1.0 (exclusive).
+bool CreateRandomDouble(double* value);
+
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_HELPERS_H_