// Written in the D programming language. /** * Convert Win32 error code to string. * * Copyright: Copyright The D Language Foundation" 2006 - 2013. * License:   $(HTTP www.boost.org/LICENSE_1_0.txt, Boost License 1.0). * Authors:   $(HTTP digitalmars.com, Walter Bright) * Credits:   Based on code written by Regan Heath *//*          Copyright The D Language Foundation" 2006 - 2013. * Distributed under the Boost Software License, Version 1.0. *    (See accompanying file LICENSE_1_0.txt or copy at *          http://www.boost.org/LICENSE_1_0.txt) */module std.windows.syserror;import std.traits : isSomeString; version (StdDdoc){    private    {        alias DWORD = uint;        enum LANG_NEUTRAL = 0, SUBLANG_DEFAULT = 1;    }     /** Query the text for a Windows error code, as returned by        $(LINK2 http://msdn.microsoft.com/en-us/library/windows/desktop/ms679360.aspx,        `GetLastError`), as a D string.     */    string sysErrorString(        DWORD errCode,        // MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT) is the user's default language        int langId = LANG_NEUTRAL,        int subLangId = SUBLANG_DEFAULT) @trusted;     /*********************       Thrown if errors that set       $(LINK2 http://msdn.microsoft.com/en-us/library/windows/desktop/ms679360.aspx,       `GetLastError`) occur.     */    class WindowsException : Exception    {        private alias DWORD = int;        final @property DWORD code(); /// `GetLastError`'s return value.        this(DWORD code, string str=null, string file = null, size_t line = 0) nothrow @trusted;    }     /++        If `!!value` is true, `value` is returned. Otherwise,        $(D new WindowsException(GetLastError(), msg)) is thrown.        `WindowsException` assumes that the last operation set        `GetLastError()` appropriately.         Example:        --------------------        wenforce(DeleteFileA("junk.tmp"), "DeleteFile failed");        --------------------     +/    T wenforce(T, S)(T value, lazy S msg = null,        string file = __FILE__, size_t line = __LINE__) @safe    if (isSomeString!S);}else: version (Windows): import core.sys.windows.winbase, core.sys.windows.winnt;import std.array : appender, Appender;import std.conv : to, toTextRange, text;import std.exception; string sysErrorString(    DWORD errCode,    // MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT) is the user's default language    int langId = LANG_NEUTRAL,    int subLangId = SUBLANG_DEFAULT) @trusted{    auto buf = appender!string();     wenforce(        // Ignore unlikely UTF decoding errors, always report the actual error (`errCode`)        putSysError(errCode, buf, MAKELANGID(langId, subLangId)).ifThrown(false),        text("Could not fetch error string for WinAPI code ", errCode)    );     return buf.data;} @safe unittest{    import std.algorithm.searching;     assert(sysErrorString(ERROR_PATH_NOT_FOUND) !is null);     const msg = collectExceptionMsg!WindowsException(sysErrorString(DWORD.max));    assert(msg.startsWith(`Could not fetch error string for WinAPI code 4294967295: `));} bool putSysError(Writer)(DWORD code, Writer w, /*WORD*/int langId = 0){    wchar *lpMsgBuf = null;    auto res = FormatMessageW(        FORMAT_MESSAGE_ALLOCATE_BUFFER |        FORMAT_MESSAGE_FROM_SYSTEM |        FORMAT_MESSAGE_IGNORE_INSERTS,        null,        code,        langId,        cast(LPWSTR)&lpMsgBuf,        0,        null);    scope(exit) if (lpMsgBuf) LocalFree(lpMsgBuf);     if (lpMsgBuf)    {        import std.string : strip;        w.put(lpMsgBuf[0 .. res].strip());        return true;    }    else        return false;} class WindowsException : Exception{    import core.sys.windows.windef : DWORD;     final @property DWORD code() { return _code; } /// `GetLastError`'s return value.    private DWORD _code;     this(DWORD code, string str=null, string file = null, size_t line = 0) nothrow @trusted    {        _code = code;         auto buf = appender!(char[]);         if (str != null)        {            buf.put(str);            if (code)                buf.put(": ");        }         if (code && writeErrorMessage(code, buf))        {            buf.put(" (error ");            toTextRange(code, buf);            buf.put(')');        }         super(cast(immutable) buf.data, file, line);    }} /// Writes the error string associated to `code` into `buf`./// Writes `Error <code>` when the error message lookup failsprivate bool writeErrorMessage(DWORD code, ref Appender!(char[]) buf) nothrow{    bool success;    try    {        // Reset the buffer to undo partial changes        const len = buf[].length;        scope (failure) buf.shrinkTo(len);         success = putSysError(code, buf);    }    catch (Exception) {}     // Write the error code instead if we couldn't find the string    if (!success)    {        buf.put("Error ");        toTextRange(code, buf);    }     return success;} T wenforce(T, S = string)(T value, lazy S msg = null,string file = __FILE__, size_t line = __LINE__)if (isSomeString!S){    if (!value)        throw new WindowsException(GetLastError(), to!string(msg), file, line);    return value;} T wenforce(T)(T condition, const(char)[] name, const(wchar)* namez, string file = __FILE__, size_t line = __LINE__){    if (condition)        return condition;    string names;    if (!name)    {        static string trustedToString(const(wchar)* stringz) @trusted        {            import core.stdc.wchar_ : wcslen;            import std.conv : to;            auto len = wcslen(stringz);            return to!string(stringz[0 .. len]);        }         names = trustedToString(namez);    }    else        names = to!string(name);    throw new WindowsException(GetLastError(), names, file, line);} @system unittest{    import std.algorithm.searching : startsWith, endsWith;    import std.string;     auto e = collectException!WindowsException(        DeleteFileA("unexisting.txt").wenforce("DeleteFile")    );    assert(e.code == ERROR_FILE_NOT_FOUND);    assert(e.msg.startsWith("DeleteFile: "));    // can't test the entire message, as it depends on Windows locale    assert(e.msg.endsWith(" (error 2)"));     // Test code zero    e = new WindowsException(0);    assert(e.msg == "");     e = new WindowsException(0, "Test");    assert(e.msg == "Test");} @safe nothrow unittest{    import std.algorithm.searching : endsWith;     auto e = new WindowsException(ERROR_FILE_NOT_FOUND);    assert(e.msg.endsWith("(error 2)"));     e = new WindowsException(DWORD.max);    assert(e.msg == "Error 4294967295");} /// Tries to translate an error code from the Windows API to the corresponding/// error message. Returns `Error <code>` on failurepackage (std) string generateSysErrorMsg(DWORD errCode = GetLastError()) nothrow @trusted{    auto buf = appender!(char[]);    cast(void) writeErrorMessage(errCode, buf);    return cast(immutable) buf[];} nothrow @safe unittest{    assert(generateSysErrorMsg(ERROR_PATH_NOT_FOUND) !is null);    assert(generateSysErrorMsg(DWORD.max) == "Error 4294967295");}