From cce24dd64ba5c1e32cd814d9ba2c58300e58829b Mon Sep 17 00:00:00 2001
From: Sebastian Messmer <mail@smessmer.de>
Date: Wed, 22 Jul 2015 13:38:36 +0200
Subject: [PATCH] Implemented ASSERT macro

---
 assert/AssertFailed.cpp             |  1 +
 assert/AssertFailed.h               | 23 +++++++++++++++++
 assert/assert.h                     | 39 +++++++++++++++++++++++++++++
 data/FixedSizeData.h                |  5 ++--
 test/assert/assert_debug_test.cpp   | 26 +++++++++++++++++++
 test/assert/assert_release_test.cpp | 30 ++++++++++++++++++++++
 6 files changed, 122 insertions(+), 2 deletions(-)
 create mode 100644 assert/AssertFailed.cpp
 create mode 100644 assert/AssertFailed.h
 create mode 100644 assert/assert.h
 create mode 100644 test/assert/assert_debug_test.cpp
 create mode 100644 test/assert/assert_release_test.cpp

diff --git a/assert/AssertFailed.cpp b/assert/AssertFailed.cpp
new file mode 100644
index 00000000..226ef4b4
--- /dev/null
+++ b/assert/AssertFailed.cpp
@@ -0,0 +1 @@
+#include "AssertFailed.h"
diff --git a/assert/AssertFailed.h b/assert/AssertFailed.h
new file mode 100644
index 00000000..279572d3
--- /dev/null
+++ b/assert/AssertFailed.h
@@ -0,0 +1,23 @@
+#pragma once
+#ifndef MESSMER_CPP_UTILS_ASSERT_ASSERTFAILED_H
+#define MESSMER_CPP_UTILS_ASSERT_ASSERTFAILED_H
+
+#include <stdexcept>
+
+namespace cpputils {
+
+    class AssertFailed : public std::exception {
+    public:
+        AssertFailed(const std::string &message) : _message(message) { }
+
+        const char *what() const throw() override {
+            return _message.c_str();
+        }
+
+    private:
+        std::string _message;
+    };
+
+}
+
+#endif
diff --git a/assert/assert.h b/assert/assert.h
new file mode 100644
index 00000000..03482544
--- /dev/null
+++ b/assert/assert.h
@@ -0,0 +1,39 @@
+#pragma once
+#ifndef MESSMER_CPP_UTILS_ASSERT_ASSERT_H
+#define MESSMER_CPP_UTILS_ASSERT_ASSERT_H
+
+/**
+ * This implements an ASSERT(expr, msg) macro.
+ * In a debug build, it will crash and halt the program on an assert failure.
+ * In a release build, it will throw an AssertFailed exception instead, which can then be caught.
+ */
+
+#include "AssertFailed.h"
+#include <iostream>
+#include <string>
+
+namespace cpputils {
+    namespace _assert {
+        inline std::string format(const char *expr, const char *message, const char *file, int line) {
+            return std::string()+"Assertion ["+expr+"] failed in "+file+":"+std::to_string(line)+": "+message;
+        }
+
+        inline void assert_fail_release(const char *expr, const char *message, const char *file, int line) {
+            throw AssertFailed(format(expr, message, file, line));
+        }
+
+        inline void assert_fail_debug(const char *expr, const char *message, const char *file, int line) {
+            std::cerr << format(expr, message, file, line) << std::endl;
+            abort();
+        }
+    }
+}
+
+#ifdef NDEBUG
+//TODO Check whether disabling assertions in prod affects speed.
+# define ASSERT(expr, msg) (void)((expr) || (cpputils::_assert::assert_fail_release(#expr, msg, __FILE__, __LINE__),0))
+#else
+# define ASSERT(expr, msg) (void)((expr) || (cpputils::_assert::assert_fail_debug(#expr, msg, __FILE__, __LINE__),0))
+#endif
+
+#endif
diff --git a/data/FixedSizeData.h b/data/FixedSizeData.h
index a99a12ff..028a5e9e 100644
--- a/data/FixedSizeData.h
+++ b/data/FixedSizeData.h
@@ -6,6 +6,7 @@
 #include <cryptopp/cryptopp/osrng.h>
 #include <string>
 #include <cstring>
+#include "../assert/assert.h"
 
 namespace cpputils {
 
@@ -67,7 +68,7 @@ FixedSizeData<SIZE> FixedSizeData<SIZE>::CreateOSRandom() {
 
 template<unsigned int SIZE>
 FixedSizeData<SIZE> FixedSizeData<SIZE>::FromString(const std::string &data) {
-  assert(data.size() == STRING_LENGTH);
+  ASSERT(data.size() == STRING_LENGTH, "Wrong string size for parsing FixedSizeData");
   FixedSizeData<SIZE> result;
   CryptoPP::StringSource(data, true,
     new CryptoPP::HexDecoder(
@@ -85,7 +86,7 @@ std::string FixedSizeData<SIZE>::ToString() const {
       new CryptoPP::StringSink(result)
     )
   );
-  assert(result.size() == STRING_LENGTH);
+  ASSERT(result.size() == STRING_LENGTH, "Created wrongly sized string");
   return result;
 }
 
diff --git a/test/assert/assert_debug_test.cpp b/test/assert/assert_debug_test.cpp
new file mode 100644
index 00000000..748b995d
--- /dev/null
+++ b/test/assert/assert_debug_test.cpp
@@ -0,0 +1,26 @@
+#include <google/gtest/gtest.h>
+#include <google/gmock/gmock.h>
+
+//Include the ASSERT macro for a debug build
+#undef NDEBUG
+#include "../../assert/assert.h"
+
+using testing::MatchesRegex;
+
+TEST(AssertTest_DebugBuild, DoesntDieIfTrue) {
+    ASSERT(true, "bla");
+}
+
+TEST(AssertTest_DebugBuild, DiesIfFalse) {
+    EXPECT_DEATH(
+      ASSERT(false, "bla"),
+      ""
+    );
+}
+
+TEST(AssertTest_DebugBuild, AssertMessage) {
+    EXPECT_DEATH(
+      ASSERT(2==5, "my message"),
+      "Assertion \\[2==5\\] failed in .*/assert_debug_test.cpp:25: my message"
+    );
+}
\ No newline at end of file
diff --git a/test/assert/assert_release_test.cpp b/test/assert/assert_release_test.cpp
new file mode 100644
index 00000000..13c1cbca
--- /dev/null
+++ b/test/assert/assert_release_test.cpp
@@ -0,0 +1,30 @@
+#include <google/gtest/gtest.h>
+#include <google/gmock/gmock.h>
+
+//Include the ASSERT macro for a release build
+#define NDEBUG
+#include "../../assert/assert.h"
+
+using testing::MatchesRegex;
+
+TEST(AssertTest_ReleaseBuild, DoesntThrowIfTrue) {
+  ASSERT(true, "bla");
+}
+
+TEST(AssertTest_ReleaseBuild, ThrowsIfFalse) {
+  EXPECT_THROW(
+    ASSERT(false, "bla"),
+    cpputils::AssertFailed
+  );
+}
+
+TEST(AssertTest_ReleaseBuild, AssertMessage) {
+  try {
+    ASSERT(2==5, "my message");
+    FAIL();
+  } catch (const cpputils::AssertFailed &e) {
+    EXPECT_THAT(e.what(), MatchesRegex(
+        "Assertion \\[2==5\\] failed in .*/assert_release_test.cpp:23: my message"
+    ));
+  }
+}
\ No newline at end of file