shell32.go

// Copyright 2010 The W32 Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package w32

import (
    "errors"
    "fmt"
    "syscall"
    "unsafe"
)

var (
    modshell32 = syscall.NewLazyDLL("shell32.dll")

    procSHBrowseForFolder   = modshell32.NewProc("SHBrowseForFolderW")
    procSHGetPathFromIDList = modshell32.NewProc("SHGetPathFromIDListW")
    procDragAcceptFiles     = modshell32.NewProc("DragAcceptFiles")
    procDragQueryFile       = modshell32.NewProc("DragQueryFileW")
    procDragQueryPoint      = modshell32.NewProc("DragQueryPoint")
    procDragFinish          = modshell32.NewProc("DragFinish")
    procShellExecute        = modshell32.NewProc("ShellExecuteW")
    procExtractIcon         = modshell32.NewProc("ExtractIconW")
)

func SHBrowseForFolder(bi *BROWSEINFO) uintptr {
    ret, _, _ := procSHBrowseForFolder.Call(uintptr(unsafe.Pointer(bi)))

    return ret
}

func SHGetPathFromIDList(idl uintptr) string {
    buf := make([]uint16, 1024)
    procSHGetPathFromIDList.Call(
        idl,
        uintptr(unsafe.Pointer(&buf[0])))

    return syscall.UTF16ToString(buf)
}

func DragAcceptFiles(hwnd HWND, accept bool) {
    procDragAcceptFiles.Call(
        uintptr(hwnd),
        uintptr(BoolToBOOL(accept)))
}

func DragQueryFile(hDrop HDROP, iFile uint) (fileName string, fileCount uint) {
    ret, _, _ := procDragQueryFile.Call(
        uintptr(hDrop),
        uintptr(iFile),
        0,
        0)

    fileCount = uint(ret)

    if iFile != 0xFFFFFFFF {
        buf := make([]uint16, fileCount+1)

        ret, _, _ := procDragQueryFile.Call(
            uintptr(hDrop),
            uintptr(iFile),
            uintptr(unsafe.Pointer(&buf[0])),
            uintptr(fileCount+1))

        if ret == 0 {
            panic("Invoke DragQueryFile error.")
        }

        fileName = syscall.UTF16ToString(buf)
    }

    return
}

func DragQueryPoint(hDrop HDROP) (x, y int, isClientArea bool) {
    var pt POINT
    ret, _, _ := procDragQueryPoint.Call(
        uintptr(hDrop),
        uintptr(unsafe.Pointer(&pt)))

    isClientArea = false
    if ret == 1 {
        isClientArea = true
    }

    x = pt.X
    y = pt.Y

    return
}

func DragFinish(hDrop HDROP) {
    procDragFinish.Call(uintptr(hDrop))
}

func ShellExecute(hwnd HWND, lpOperation, lpFile, lpParameters, lpDirectory string, nShowCmd int) error {
    var op, param, directory uintptr
    if len(lpOperation) != 0 {
        op = uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpOperation)))
    }
    if len(lpParameters) != 0 {
        param = uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpParameters)))
    }
    if len(lpDirectory) != 0 {
        directory = uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpDirectory)))
    }

    ret, _, _ := procShellExecute.Call(
        uintptr(hwnd),
        op,
        uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpFile))),
        param,
        directory,
        uintptr(nShowCmd))

    errorMsg := ""
    if ret != 0 && ret <= 32 {
        switch int(ret) {
        case ERROR_FILE_NOT_FOUND:
            errorMsg = "The specified file was not found."
        case ERROR_PATH_NOT_FOUND:
            errorMsg = "The specified path was not found."
        case ERROR_BAD_FORMAT:
            errorMsg = "The .exe file is invalid (non-Win32 .exe or error in .exe image)."
        case SE_ERR_ACCESSDENIED:
            errorMsg = "The operating system denied access to the specified file."
        case SE_ERR_ASSOCINCOMPLETE:
            errorMsg = "The file name association is incomplete or invalid."
        case SE_ERR_DDEBUSY:
            errorMsg = "The DDE transaction could not be completed because other DDE transactions were being processed."
        case SE_ERR_DDEFAIL:
            errorMsg = "The DDE transaction failed."
        case SE_ERR_DDETIMEOUT:
            errorMsg = "The DDE transaction could not be completed because the request timed out."
        case SE_ERR_DLLNOTFOUND:
            errorMsg = "The specified DLL was not found."
        case SE_ERR_NOASSOC:
            errorMsg = "There is no application associated with the given file name extension. This error will also be returned if you attempt to print a file that is not printable."
        case SE_ERR_OOM:
            errorMsg = "There was not enough memory to complete the operation."
        case SE_ERR_SHARE:
            errorMsg = "A sharing violation occurred."
        default:
            errorMsg = fmt.Sprintf("Unknown error occurred with error code %v", ret)
        }
    } else {
        return nil
    }

    return errors.New(errorMsg)
}

func ExtractIcon(lpszExeFileName string, nIconIndex int) HICON {
    ret, _, _ := procExtractIcon.Call(
        0,
        uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(lpszExeFileName))),
        uintptr(nIconIndex))

    return HICON(ret)
}