Update monet.

crypto/openssl_util.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CRYPTO_OPENSSL_UTIL_H_
+#define CRYPTO_OPENSSL_UTIL_H_
+
+#include "base/basictypes.h"
+#include "base/location.h"
+#include "crypto/crypto_export.h"
+
+namespace crypto {
+
+// Provides a buffer of at least MIN_SIZE bytes, for use when calling OpenSSL's
+// SHA256, HMAC, etc functions, adapting the buffer sizing rules to meet those
+// of the our base wrapper APIs.
+// This allows the library to write directly to the caller's buffer if it is of
+// sufficient size, but if not it will write to temporary |min_sized_buffer_|
+// of required size and then its content is automatically copied out on
+// destruction, with truncation as appropriate.
+template<int MIN_SIZE>
+class ScopedOpenSSLSafeSizeBuffer {
+ public:
+  ScopedOpenSSLSafeSizeBuffer(unsigned char* output, size_t output_len)
+      : output_(output),
+        output_len_(output_len) {
+  }
+
+  ~ScopedOpenSSLSafeSizeBuffer() {
+    if (output_len_ < MIN_SIZE) {
+      // Copy the temporary buffer out, truncating as needed.
+      memcpy(output_, min_sized_buffer_, output_len_);
+    }
+    // else... any writing already happened directly into |output_|.
+  }
+
+  unsigned char* safe_buffer() {
+    return output_len_ < MIN_SIZE ? min_sized_buffer_ : output_;
+  }
+
+ private:
+  // Pointer to the caller's data area and its associated size, where data
+  // written via safe_buffer() will [eventually] end up.
+  unsigned char* output_;
+  size_t output_len_;
+
+  // Temporary buffer writen into in the case where the caller's
+  // buffer is not of sufficient size.
+  unsigned char min_sized_buffer_[MIN_SIZE];
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSLSafeSizeBuffer);
+};
+
+// Initialize OpenSSL if it isn't already initialized. This must be called
+// before any other OpenSSL functions though it is safe and cheap to call this
+// multiple times.
+// This function is thread-safe, and OpenSSL will only ever be initialized once.
+// OpenSSL will be properly shut down on program exit.
+void CRYPTO_EXPORT EnsureOpenSSLInit();
+
+// Drains the OpenSSL ERR_get_error stack. On a debug build the error codes
+// are send to VLOG(1), on a release build they are disregarded. In most
+// cases you should pass FROM_HERE as the |location|.
+void CRYPTO_EXPORT ClearOpenSSLERRStack(
+    const tracked_objects::Location& location);
+
+// Place an instance of this class on the call stack to automatically clear
+// the OpenSSL error stack on function exit.
+class OpenSSLErrStackTracer {
+ public:
+  // Pass FROM_HERE as |location|, to help track the source of OpenSSL error
+  // messages. Note any diagnostic emitted will be tagged with the location of
+  // the constructor call as it's not possible to trace a destructor's callsite.
+  explicit OpenSSLErrStackTracer(const tracked_objects::Location& location)
+      : location_(location) {
+    EnsureOpenSSLInit();
+  }
+  ~OpenSSLErrStackTracer() {
+    ClearOpenSSLERRStack(location_);
+  }
+
+ private:
+  const tracked_objects::Location location_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(OpenSSLErrStackTracer);
+};
+
+}  // namespace crypto
+
+#endif  // CRYPTO_OPENSSL_UTIL_H_