nix-super/src/libutil/windows/file-descriptor.cc

#include "file-system.hh"
#include "signals.hh"
#include "finally.hh"
#include "serialise.hh"
#include "windows-error.hh"
#include "file-path.hh"

#include <fileapi.h>
#include <error.h>
#include <namedpipeapi.h>
#include <namedpipeapi.h>
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

namespace nix {

using namespace nix::windows;

std::string readFile(HANDLE handle)
{
    LARGE_INTEGER li;
    if (!GetFileSizeEx(handle, &li))
        throw WinError("%s:%d statting file", __FILE__, __LINE__);

    return drainFD(handle, true, li.QuadPart);
}


void readFull(HANDLE handle, char * buf, size_t count)
{
    while (count) {
        checkInterrupt();
        DWORD res;
        if (!ReadFile(handle, (char *) buf, count, &res, NULL))
            throw WinError("%s:%d reading from file", __FILE__, __LINE__);
        if (res == 0) throw EndOfFile("unexpected end-of-file");
        count -= res;
        buf += res;
    }
}


void writeFull(HANDLE handle, std::string_view s, bool allowInterrupts)
{
    while (!s.empty()) {
        if (allowInterrupts) checkInterrupt();
        DWORD res;
#if _WIN32_WINNT >= 0x0600
        auto path = handleToPath(handle); // debug; do it before becuase handleToPath changes lasterror
        if (!WriteFile(handle, s.data(), s.size(), &res, NULL)) {
            throw WinError("writing to file %1%:%2%", handle, path);
        }
#else
        if (!WriteFile(handle, s.data(), s.size(), &res, NULL)) {
            throw WinError("writing to file %1%", handle);
        }
#endif
        if (res > 0)
            s.remove_prefix(res);
    }
}


std::string readLine(HANDLE handle)
{
    std::string s;
    while (1) {
        checkInterrupt();
        char ch;
        // FIXME: inefficient
        DWORD rd;
        if (!ReadFile(handle, &ch, 1, &rd, NULL)) {
            throw WinError("reading a line");
        } else if (rd == 0)
            throw EndOfFile("unexpected EOF reading a line");
        else {
            if (ch == '\n') return s;
            s += ch;
        }
    }
}


void drainFD(HANDLE handle, Sink & sink/*, bool block*/)
{
    std::vector<unsigned char> buf(64 * 1024);
    while (1) {
        checkInterrupt();
        DWORD rd;
        if (!ReadFile(handle, buf.data(), buf.size(), &rd, NULL)) {
            WinError winError("%s:%d reading from handle %p", __FILE__, __LINE__, handle);
            if (winError.lastError == ERROR_BROKEN_PIPE)
                break;
            throw winError;
        }
        else if (rd == 0) break;
        sink({(char *) buf.data(), (size_t) rd});
    }
}


//////////////////////////////////////////////////////////////////////


void Pipe::create()
{
    SECURITY_ATTRIBUTES saAttr = {0};
    saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
    saAttr.lpSecurityDescriptor = NULL;
    saAttr.bInheritHandle = TRUE;

    HANDLE hReadPipe, hWritePipe;
    if (!CreatePipe(&hReadPipe, &hWritePipe, &saAttr, 0))
        throw WinError("CreatePipe");

    readSide = hReadPipe;
    writeSide = hWritePipe;
}


//////////////////////////////////////////////////////////////////////

#if _WIN32_WINNT >= 0x0600

std::wstring windows::handleToFileName(HANDLE handle) {
    std::vector<wchar_t> buf(0x100);
    DWORD dw = GetFinalPathNameByHandleW(handle, buf.data(), buf.size(), FILE_NAME_OPENED);
    if (dw == 0) {
        if (handle == GetStdHandle(STD_INPUT_HANDLE )) return L"<stdin>";
        if (handle == GetStdHandle(STD_OUTPUT_HANDLE)) return L"<stdout>";
        if (handle == GetStdHandle(STD_ERROR_HANDLE )) return L"<stderr>";
        return (boost::wformat(L"<unnnamed handle %X>") % handle).str();
    }
    if (dw > buf.size()) {
        buf.resize(dw);
        if (GetFinalPathNameByHandleW(handle, buf.data(), buf.size(), FILE_NAME_OPENED) != dw-1)
            throw WinError("GetFinalPathNameByHandleW");
        dw -= 1;
    }
    return std::wstring(buf.data(), dw);
}


Path windows::handleToPath(HANDLE handle) {
    return os_string_to_string(handleToFileName(handle));
}

#endif

}