gfx/src/psshared/nsCUPSShim.cpp
author Matthew Gregan <kinetik@flim.org>
Wed, 29 Dec 2010 13:03:25 +0100
changeset 34843 ffa1ef8ab52b
parent 1 9b2a99adc05e
permissions -rw-r--r--
Bug 573039 - Construct nsCUPSShim statically and avoid calling PR_UnloadLibrary on libcups after it has been initialized. r=karlt a=clegnitto
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ex: set tabstop=8 softtabstop=4 shiftwidth=4 expandtab: */
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
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 * 1.1 (the "License"); you may not use this file except in compliance with
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 * The Original Code is the Mozilla PostScript driver printer list component.
 *
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#include "nsDebug.h"
#include "nsString.h"
#include "nsCUPSShim.h"
#include "prlink.h"


// List of symbols to find in libcups. Must match symAddr[] defined in Init().
// Making this an array of arrays instead of pointers allows storing the
// whole thing in read-only memory.
static const char gSymName[][sizeof("cupsPrintFile")] = {
    { "cupsAddOption" },
    { "cupsFreeDests" },
    { "cupsGetDest" },
    { "cupsGetDests" },
    { "cupsPrintFile" },
    { "cupsTempFd" },
};
static const int gSymNameCt = sizeof(gSymName) / sizeof(gSymName[0]);


PRBool
nsCUPSShim::Init()
{
    mCupsLib = PR_LoadLibrary("libcups.so.2");
    if (!mCupsLib)
        return PR_FALSE;

    // List of symbol pointers. Must match gSymName[] defined above.
    void **symAddr[] = {
        (void **)&mCupsAddOption,
        (void **)&mCupsFreeDests,
        (void **)&mCupsGetDest,
        (void **)&mCupsGetDests,
        (void **)&mCupsPrintFile,
        (void **)&mCupsTempFd,
    };

    for (int i = gSymNameCt; i--; ) {
        *(symAddr[i]) = PR_FindSymbol(mCupsLib, gSymName[i]);
        if (! *(symAddr[i])) {
#ifdef DEBUG
            nsCAutoString msg(gSymName[i]);
            msg.Append(" not found in CUPS library");
            NS_WARNING(msg.get());
#endif
            PR_UnloadLibrary(mCupsLib);
            mCupsLib = nsnull;
            return PR_FALSE;
        }
    }
    return PR_TRUE;
}