android + common: fix warnings

src/android/app/src/main/jni/native.cpp

@@ -56,35 +56,6 @@ std::condition_variable running_cv;
 
 } // Anonymous namespace
 
-static bool DisplayAlertMessage(const char* caption, const char* text, bool yes_no) {
-    JNIEnv* env = IDCache::GetEnvForThread();
-
-    // Execute the Java method.
-    jboolean result = env->CallStaticBooleanMethod(
-        IDCache::GetNativeLibraryClass(), IDCache::GetDisplayAlertMsg(), ToJString(env, caption),
-        ToJString(env, text), yes_no ? JNI_TRUE : JNI_FALSE);
-
-    return result != JNI_FALSE;
-}
-
-static std::string DisplayAlertPrompt(const char* caption, const char* text, int buttonConfig) {
-    JNIEnv* env = IDCache::GetEnvForThread();
-
-    jstring value = reinterpret_cast<jstring>(env->CallStaticObjectMethod(
-        IDCache::GetNativeLibraryClass(), IDCache::GetDisplayAlertPrompt(), ToJString(env, caption),
-        ToJString(env, text), buttonConfig));
-
-    return GetJString(env, value);
-}
-
-static int AlertPromptButton() {
-    JNIEnv* env = IDCache::GetEnvForThread();
-
-    // Execute the Java method.
-    return static_cast<int>(env->CallStaticIntMethod(IDCache::GetNativeLibraryClass(),
-                                                     IDCache::GetAlertPromptButton()));
-}
-
 static jobject ToJavaCoreError(Core::System::ResultStatus result) {
     static const std::map<Core::System::ResultStatus, const char*> CoreErrorNameMap{
         {Core::System::ResultStatus::ErrorSystemFiles, "ErrorSystemFiles"},

src/common/file_util.cpp

@@ -102,12 +102,11 @@ static void StripTailDirSlashes(std::string& fname) {
 }
 
 bool Exists(const std::string& filename) {
-    struct stat file_info;
-
     std::string copy(filename);
     StripTailDirSlashes(copy);
 
 #ifdef _WIN32
+    struct stat file_info;
     // Windows needs a slash to identify a driver root
     if (copy.size() != 0 && copy.back() == ':')
         copy += DIR_SEP_CHR;
@@ -116,6 +115,7 @@ bool Exists(const std::string& filename) {
 #elif ANDROID
     int result = AndroidStorage::FileExists(filename) ? 0 : -1;
 #else
+    struct stat file_info;
     int result = stat(copy.c_str(), &file_info);
 #endif
 
@@ -699,7 +699,7 @@ static const std::string& GetHomeDirectory() {
  * @return The directory path
  * @sa http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
  */
-static const std::string GetUserDirectory(const std::string& envvar) {
+[[maybe_unused]] static const std::string GetUserDirectory(const std::string& envvar) {
     const char* directory = getenv(envvar.c_str());
 
     std::string user_dir;

src/common/misc.cpp

@@ -16,19 +16,33 @@
 // Call directly after the command or use the error num.
 // This function might change the error code.
 std::string GetLastErrorMsg() {
-    constexpr std::size_t buff_size = 255;
-    char err_str[buff_size];
-    std::size_t msg_len;
-
 #ifdef _WIN32
-    msg_len =
-        FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM, nullptr, GetLastError(),
-                       MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), err_str, buff_size, nullptr);
+    LPSTR err_str;
+
+    DWORD res = FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER |
+                                   FORMAT_MESSAGE_IGNORE_INSERTS,
+                               nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+                               reinterpret_cast<LPSTR>(&err_str), 1, nullptr);
+    if (!res) {
+        return "(FormatMessageA failed to format error)";
+    }
+    std::string ret(err_str);
+    LocalFree(err_str);
+    return ret;
+#else
+    char err_str[255];
+#if (defined(__GLIBC__) || __ANDROID_API__ >= 23) &&                                               \
+    (_GNU_SOURCE || (_POSIX_C_SOURCE < 200112L && _XOPEN_SOURCE < 600))
+    // Thread safe (GNU-specific)
+    const char* str = strerror_r(errno, err_str, sizeof(err_str));
+    return std::string(str);
 #else
     // Thread safe (XSI-compliant)
-    strerror_r(errno, err_str, buff_size);
-    msg_len = strnlen(err_str, buff_size);
-#endif
-
-    return std::string(err_str, msg_len);
+    int second_err = strerror_r(errno, err_str, sizeof(err_str));
+    if (second_err != 0) {
+        return "(strerror_r failed to format error)";
+    }
+    return std::string(err_str);
+#endif // GLIBC etc.
+#endif // _WIN32
 }