internal static extern int LoadString(SafeLibraryHandle handle, int id, [Out] StringBuilder buffer, int bufferLength);
// FormatMessageW will AV if you don't pass in enough format strings. If you call TryFormatMessage we ensure insertionStrings
// is long enough. You don't want to call this directly unless you're sure insertionStrings is long enough!
internal static string UnsafeTryFormatMessage(SafeLibraryHandle hModule, uint messageNum, string[] insertionStrings) {
string msg = null;
int msgLen = 0;
StringBuilder buf = new StringBuilder(1024);
int flags = NativeMethods.FORMAT_MESSAGE_FROM_HMODULE | NativeMethods.FORMAT_MESSAGE_ARGUMENT_ARRAY;
IntPtr[] addresses = new IntPtr[insertionStrings.Length];
GCHandle[] handles = new GCHandle[insertionStrings.Length];
GCHandle stringsRoot = GCHandle.Alloc(addresses, GCHandleType.Pinned);
// Make sure that we don't try to pass in a zero length array of addresses. If there are no insertion strings,
// we'll use the FORMAT_MESSAGE_IGNORE_INSERTS flag .
// If you change this behavior, make sure you look at TryFormatMessage which depends on this behavior!
if (insertionStrings.Length == 0) {
flags |= NativeMethods.FORMAT_MESSAGE_IGNORE_INSERTS;
}
try {
for (int i=0; i<handles.Length; i++) {
handles[i] = GCHandle.Alloc(insertionStrings[i], GCHandleType.Pinned);
addresses[i] = handles[i].AddrOfPinnedObject();
}
int lastError = NativeMethods.ERROR_INSUFFICIENT_BUFFER;
while (msgLen == 0 && lastError == NativeMethods.ERROR_INSUFFICIENT_BUFFER) {
msgLen = SafeNativeMethods.FormatMessage(
flags,
hModule,
messageNum,
0,
buf,
buf.Capacity,
addresses);
if (msgLen == 0) {
lastError = Marshal.GetLastWin32Error();
if (lastError == NativeMethods.ERROR_INSUFFICIENT_BUFFER)
buf.Capacity = buf.Capacity * 2;
}
}
}
catch {
msgLen = 0; // return empty on failure
}
finally {
for (int i=0; i<handles.Length; i++) {
if (handles[i].IsAllocated) handles[i].Free();
}
stringsRoot.Free();
}
if (msgLen > 0) {
msg = buf.ToString();
// chop off a single CR/LF pair from the end if there is one. FormatMessage always appends one extra.
if (msg.Length > 1 && msg[msg.Length-1] == '\n')
msg = msg.Substring(0, msg.Length-2);
}
return msg;
}
public static unsafe extern int FormatMessage(int dwFlags, SafeLibraryHandle lpSource, uint dwMessageId,
int dwLanguageId, StringBuilder lpBuffer, int nSize, IntPtr[] arguments);
// Format message in specific DLL. Return <null> on failure.
internal static string TryFormatMessage(SafeLibraryHandle hModule, uint messageNum, string[] insertionStrings) {
if (insertionStrings.Length == 0) {
// UnsafeTryFromatMessage will set FORMAT_MESSAGE_IGNORE_INSERTS when calling into the OS
// when there are no insertion strings, in this case we don't have to guard against insertionStrings
// not having enough data since it is unused when FORMAT_MESSAGE_IGNORE_INSERTS is specified
return UnsafeTryFormatMessage(hModule, messageNum, insertionStrings);
}
// If you pass in an empty array UnsafeTryFormatMessage will just pull out the message.
string formatString = UnsafeTryFormatMessage(hModule, messageNum, new string[0]);
if (formatString == null) {
return null;
}
int largestNumber = 0;
for (int i = 0; i < formatString.Length; i++) {
if (formatString[i] == '%') {
// See if a number follows this, if so, grab the number.
if(formatString.Length > i + 1) {
StringBuilder sb = new StringBuilder();
while (i + 1 < formatString.Length && Char.IsDigit(formatString[i + 1])) {
sb.Append(formatString[i + 1]);
i++;
}
// move over the non number character that broke us out of the loop
i++;
if (sb.Length > 0) {
int num = -1;
if (Int32.TryParse(sb.ToString(), NumberStyles.None, CultureInfo.InvariantCulture, out num)) {
largestNumber = Math.Max(largestNumber, num);
}
}
}
}
}
// Replacement strings are 1 indexed.
if (largestNumber > insertionStrings.Length) {
string[] newStrings = new string[largestNumber];
Array.Copy(insertionStrings, newStrings, insertionStrings.Length);
for (int i = insertionStrings.Length; i < newStrings.Length; i++) {
newStrings[i] = "%" + (i + 1);
}
insertionStrings = newStrings;
}
return UnsafeTryFormatMessage(hModule, messageNum, insertionStrings);
}
internal static extern int LoadString(SafeLibraryHandle handle, int id, StringBuilder buffer, int bufferLength);
