// 

/**************************************************************************\
 * Copyright (c) Kongsberg Oil & Gas Technologies AS
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of the copyright holder nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\**************************************************************************/

/*!
  \class SoAny SoAny.h
  \brief The SoAny class is a collection of common toolkit methods.

  SoAny contains internal (i.e. not accessible to the application
  programmer) functionality which needs to be "globally" visible to
  all parts of the toolkit.
*/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /* HAVE_CONFIG_H */

#ifdef HAVE_WINDOWS_H
#include <windows.h> /* GetEnvironmentVariable() */
#endif /* HAVE_WINDOWS_H */

#include <cstdlib>
#include <cstring>
#include <cassert>

#include <Inventor/errors/SoDebugError.h>
#include <Inventor/elements/SoGLCacheContextElement.h>
#include <Inventor/nodes/SoSeparator.h>
#include <Inventor/actions/SoSearchAction.h>
#include <Inventor/SoInput.h>
#include <Inventor/SoDB.h>
#include <Inventor/Qt/SoQtObject.h>
#include <Inventor/Qt/SoQtCursor.h>
#include <Inventor/Qt/nodes/SoGuiNodes.h>
#include <Inventor/Qt/engines/SoGuiEngines.h>

#include <Inventor/Qt/SoAny.h>

static SoAny * single_instance = NULL;

SoSearchAction * SoAny::finder = NULL;

// Following block explains OpenGL cache context handling in some
// depth. Copied from an email write-up by pederb:
//
// The SoGui toolkits use the SoAny class to handle cache context ids
// and cache context id sharing (cache context ids can be shared on
// Windows and on Unix if the display and screen are equal).
//
// E.g. in SoQt, when a new GL-widget is created, it is registered
// using SoAny::registerGLContext (from SoQtGLWidget.cpp). When the
// GL-widget is destructed, SoAny::unregisterGLContext() must be
// called. Then, in SoGuiRenderArea::initGraphic(),
// SoAny::getSharedCacheContextId() is called to find a valid cache
// context id for SoGLRenderAction.
//
// What one needs to do is to detect when the GL-context is
// destructed, and then call SoAny::unregisterGLContext(). Then
// SoAny::registerGLContext() to register the new context, and then
// set the new cache context id in the SoGLRenderAction. This can
// probably be done just by calling SoGuiRenderArea::initGraphic().

class soany_cache_context {
public:
  soany_cache_context(void * display, void * screen)
    : display(display), screen(screen), cacheid(-1) { } 
  ~soany_cache_context() { }

  SbBool isSameCacheContext(void * displayarg, void * screenarg) const {
    return (this->display == displayarg && this->screen == screenarg);
  }
  SbBool findContext(void * context) const {
    for (int i = 0; i < this->contextlist.getLength(); i++) {
      if (this->contextlist[i] == context) return TRUE;
    }
    return FALSE;
  }
  void * getFirstContext(void) const {
    assert(this->contextlist.getLength());
    return this->contextlist[0];
  }
  void addContext(void * context) {
    assert(!this->findContext(context));
    this->contextlist.append(context);
  }

  SbBool tryRemoveContext(void * context) {
    for (int i = 0; i < this->contextlist.getLength(); i++) {
      if (this->contextlist[i] == context) {
        this->contextlist.remove(i);
        return TRUE;
      }
    }
    return FALSE;
  }
  SbBool isEmpty(void) const {
    return this->contextlist.getLength() == 0;
  }
  int getCacheContextId(void) {
    if (this->cacheid < 0) {
#ifdef __COIN__
      // Coin has a method for generating an unique cache context id.
      // Unfortunately, this method does not exists for SGI/TGS Inventor.
      this->cacheid = (int) SoGLCacheContextElement::getUniqueCacheContext();
#else // ! __COIN__
      this->cacheid = soany_cache_context::oiv_counter++;
#endif // ! __COIN__
    }
    return this->cacheid;
  }

private:
  void * display;
  void * screen;
  int cacheid;
  SbPList contextlist;
  static int oiv_counter;
};

#if 0 // FIXME: not sure if this is ok, check with pederb. 20010806 mortene.
// A semi-random magic number -- we want to avoid crashing with any
// cache context id values internally used in SGI / TGS OIV as magic
// numbers.
int soany_cache_context::oiv_counter = 4242;
#else
int soany_cache_context::oiv_counter = 0;
#endif

// *************************************************************************

static void soany_atexit_cleanup(void);

void
SoAny::init()
{
  SoQtObject::init();
  SoQtCursor::initClass();
  SoGuiNodes::initClasses();
  SoGuiEngines::initClasses();
  SoAny::atexit((SoAny::atexit_f*)soany_atexit_cleanup, 0);
  SoAny::atexit((SoAny::atexit_f*)SoAny::cleanup_si, 0);
}

// private constructor
SoAny::SoAny(void) 
  : fatalcb(NULL)
{
}
 
// private destructor
SoAny::~SoAny()
{
  for (int i = 0; i < this->cclist.getLength(); i++) {
    delete (soany_cache_context*) this->cclist[i];
  }
}

/*!
  Returns pointer to the single instance of this class (implemented
  according to the singleton design pattern).
*/
SoAny * 
SoAny::si(void)
{
  if (single_instance == NULL) single_instance = new SoAny;
  return single_instance;
}

//  Free memory/resources used by the singleton object. Will be called
//  automatically on exit.
void 
SoAny::cleanup_si(void)
{
  delete single_instance;
  single_instance = NULL;
  delete SoAny::finder;
  SoAny::finder = NULL;
}

/*!  
  Returns a pointer to any previous context with which GL sharing
  is possible, or \e NULL if none found.  
*/
void * 
SoAny::getSharedGLContext(void * display, void * screen)
{
  for (int i = 0; i < this->cclist.getLength(); i++) {
    soany_cache_context * cc = (soany_cache_context*) this->cclist[i];
    if (cc->isSameCacheContext(display, screen)) {
      return cc->getFirstContext();
    }
  }
  return NULL;
}

/*!
  Adds GL context information. Might be platform dependent what the \a
  display and \a screen will be. Call this method once when the
  context is created. In the Coin GUI toolkits, \a context will be a
  pointer to a SoQtGLWidget.
*/
void 
SoAny::registerGLContext(void * context, void * display, void * screen)
{
#if SOQT_DEBUG && 0 // debug
  SoDebugError::postInfo("SoAny::registerGLContext",
                         "context==%p, display==%p, screen==%p",
                         context, display, screen);
#endif // debug

  int i, n = this->cclist.getLength();
  for (i = 0; i < n; i++) {
    soany_cache_context * cc = (soany_cache_context*) this->cclist[i];
    if (cc->isSameCacheContext(display, screen)) break;
  }
  if (i == n) this->cclist.append(new soany_cache_context(display, screen));
  soany_cache_context * cc = (soany_cache_context*) this->cclist[i];
  cc->addContext(context);
}

/*!
  Removes a GL context from the list of contexts. Should be called
  when the context/widget is destructed.
*/
void 
SoAny::unregisterGLContext(void * context)
{
#if SOQT_DEBUG && 0 // debug
  SoDebugError::postInfo("SoAny::unregisterGLContext", "context==%p", context);
#endif // debug

  for (int i = 0; i < this->cclist.getLength(); i++) {
    soany_cache_context * cc = (soany_cache_context*) this->cclist[i];
    if (cc->tryRemoveContext(context)) {
      if (cc->isEmpty()) {
        delete cc;
        this->cclist.remove(i);
      }
      return;
    }
  }
  assert(FALSE && "couldn't find context in internal list");
}

/*!
  Returns a shared cache context id, to be used as argument
  in SoGLRenderAction::setCacheContext().
*/
int 
SoAny::getSharedCacheContextId(void * context)
{
  for (int i = 0; i < this->cclist.getLength(); i++) {
    soany_cache_context * cc = (soany_cache_context*) this->cclist[i];
    if (cc->findContext(context)) return cc->getCacheContextId();
  }
#if SOQT_DEBUG
  SoDebugError::post("SoAny::getSharedCacheContextId",
                     "could not find shared cache context for context %p "
                     "(shared context handling not implemented for this "
                     "toolkit?)", context);
#endif // SOQT_DEBUG
  return 0;
}

/*!
  Set up a fatal error handler in case of "impossible" errors.  Calls
  to this function are calls forwarded from
  SoQt::setFatalErrorHandler().

  Returns previous fatal error handler callback, or \c NULL if none.

  \sa SoQt::setFatalErrorHandler()
 */
SoQt::FatalErrorCB *
SoAny::setFatalErrorHandler(SoQt::FatalErrorCB * cb, void * userdataarg)
{
  SoQt::FatalErrorCB * oldcb = this->fatalcb;
  this->fatalcb = cb;
  this->userdata = userdataarg;
  return oldcb;
}

/*!
  In the case of a fatal error condition in the library, this method
  should be used to invoke the application fatal error handler.

  Returns \c TRUE if an error handler was set up, or \c FALSE if none.

  If no handler was set up, a dialog box with the error string will be
  shown and then the application will exit.

  A very important issue to be aware of for "client code" around in
  the So*-libraries is that this function will not return if the
  application programmer has set up a fatal error handler which throws
  an exception. Because of this, the "as good as possible" clean-up
  code around the points of fatal error failures needs to be executed
  \e before calling this function.

  \sa SoAny::setFatalErrorHandler()
 */
SbBool
SoAny::invokeFatalErrorHandler(SbString errmsg, SoQt::FatalErrors errcode)
{
  // First trigger the internal clean-up routines.
  int internals = this->internalfehandlers.getLength();
  for (int idx = 0; idx < internals; idx++) {
    SoAny::InternalFatalErrorCB * cb =
      (SoAny::InternalFatalErrorCB *)this->internalfehandlers[idx];
    (*cb)(this->internalfedata[idx]);
  }

  // If no app-programmer registered callback, throw up our own
  // message dialog.
  if (this->fatalcb == NULL) {
    SoQt::createSimpleErrorDialog(NULL,
                                     "Fatal application error",
                                     errmsg.getString(),
                                     "Application will exit.");
    return FALSE;
  }

  fatalcb(errmsg, errcode, this->userdata);
  return TRUE;
}


/*!
  Lets us register an internal callback to run when a fatal error is
  detected.

  Internal clean-up functions are sometimes necessary because we set up
  external references to internal resources which may not be valid
  after a fatal error hits.
*/
void
SoAny::addInternalFatalErrorHandler(SoAny::InternalFatalErrorCB * cb,
                                    void * userdataarg)
{
  this->internalfehandlers.append((void *)cb);
  this->internalfedata.append(userdataarg);
}


/**************************************************************************/

/*** Single linked list for the environment variables. ********************/

/*
  FIXME: should implement a generic (macro-based) single linked list
  abstraction in C (the following code could be a good starting
  point). Then axe this code. Then move the various list handling stuff
  in the Coin library from the SbList<> template to the C-based one to
  aid any future transition to pure C. 20010821 mortene.

  UPDATE: SbList isn't really a linked list, but in fact a growable
  array -- so the code below can not be used as a replacement. Still,
  we should have a generic linked list class. 20011220 mortene.
*/

static struct envvar_data * envlist_head = NULL;
static struct envvar_data * envlist_tail = NULL;

struct envvar_data {
  char * name;
  char * val;
  struct envvar_data * next;
};

static void
envlist_append(struct envvar_data * item)
{
  item->next = NULL;
  if (envlist_head == NULL) {
    envlist_head = item;
    envlist_tail = item;
  }
  else {
    envlist_tail->next = item;
    envlist_tail = item;
  }
}

/**************************************************************************/

/*
  When working with Microsoft Windows applications using the library as a DLL,
  setenv() / getenv() will not work as expected, as the application
  and the DLL have different instances of the C library with different
  data structures on different heaps. That's why we need this
  abstraction around the C-libs getenv() vs the Win32 API
  GetEnvironmentVariable() function.

  Note: do not deallocate the returned string -- they are supposed to
  be permanently available to all callers. Deallocating the resources
  is the responsibility of the application exit cleanup code.
*/

const char *
SoAny::getenv(const char * envname)
{
  /* Important note: this code is duplicated in Coin, Coin-1,
     SoQt/.../common/SoAny.cpp.in (and possibly stable forks of the
     toolkits).  If you do bug fixes or whatever, keep them in sync! */
#ifdef HAVE_GETENVIRONMENTVARIABLE
  int neededsize;
  neededsize = GetEnvironmentVariableA(envname, NULL, 0);
  /* neededsize includes the \0-terminating character */
  if ( neededsize >= 1 ) {
    int resultsize;
    struct envvar_data * envptr;
    char * valbuf = (char *) malloc(neededsize);
    if ( valbuf == NULL ) {
      /* Augh. Could we handle this any better? */
      /* If we already bookkeep a buffer for this variable, we /could/ try
         to reuse it (much work for a non-100% solution).  20030205 larsa */
      return NULL;
    }
    resultsize = GetEnvironmentVariableA(envname, valbuf, neededsize);
    if ( resultsize != (neededsize - 1) ) {
      /* Augh. Could we handle this any better? */
      /* How about looping to top and trying again (in case the reason is mt
         and envval being changed in the background, or maybe just asserting?
         20030205 larsa */
      free(valbuf);
      return NULL;
    }

    /*
      The GetEnvironmentVariable() signature forces us to allocate the space
      for the value string on the outside of the call, as opposed to the UNIX
      getenv() function.  We therefore have to do bookkeeping and maintain
      this linked list of allocated buffers that should be cleaned up on exit
      (atexit()).  We don't keep it for lookup of values - we actually can't
      use the values as value caches in case they have been changed from other
      parts of the application.  We only keep them so we can free them later.
    */

    /* Try to find bookkeeped envvar buffer among those registered earlier. */
    envptr = envlist_head;
    while ( (envptr != NULL) && (strcmp(envptr->name, envname) != 0) )
      envptr = envptr->next;

    /* We can avoid this if-else by always freeing the envvar_data for the
       variable upfront, but it's a tad less efficient. */
    if ( envptr != NULL ) {
      /* We are already bookkeeping a buffer for this variable.
       * => free previous value buffer and bookkeep the new one instead */
      free(envptr->val);
      envptr->val = valbuf;
    } else {
      /* We aren't bookkeeping a buffer for this one yet. */
      envptr = (struct envvar_data *) malloc(sizeof(struct envvar_data));
      if ( envptr == NULL ) {
        /* Augh. Could we handle this any better? */
	/* We can alternatively ignore the bookkeeping and leak the buffer
           - 20030205 larsa */
        free(valbuf);
        return NULL;
      }
      envptr->name = strdup(envname);
      if ( envptr->name == NULL ) {
        /* Augh. Could we handle this any better? */
	/* We can alternatively ignore the bookkeeping and leak the buffer
           - 20030205 larsa */
	free(envptr);
	free(valbuf);
	return NULL;
      }
      envptr->val = valbuf;
      envlist_append(envptr);
    }
    return envptr->val;
  }
  return NULL;
#else /* !HAVE_GETENVIRONMENTVARIABLE */
  return ::getenv(envname);
#endif /* !HAVE_GETENVIRONMENTVARIABLE */
}

/**************************************************************************/

#if defined(HAVE_WIN32_LOADLIBRARY) && defined(HAVE_TLHELP32_H)

#include <tlhelp32.h>


typedef HANDLE (WINAPI * CreateToolhelp32Snapshot_t)(DWORD, DWORD);
typedef BOOL (WINAPI * Module32First_t)(HANDLE, LPMODULEENTRY32);
typedef BOOL (WINAPI * Module32Next_t)(HANDLE, LPMODULEENTRY32);

static CreateToolhelp32Snapshot_t funCreateToolhelp32Snapshot = NULL;
static Module32First_t funModule32First = NULL;
static Module32Next_t funModule32Next = NULL;


void
SoAny::listWin32ProcessModules(void)
{
  BOOL ok;

  HINSTANCE kernel32dll = LoadLibraryA("kernel32.dll");
  assert(kernel32dll && "LoadLibraryA(''kernel32.dll'') failed");

  funCreateToolhelp32Snapshot = (CreateToolhelp32Snapshot_t)
    GetProcAddress(kernel32dll, "CreateToolhelp32Snapshot");
  funModule32First = (Module32First_t)
    GetProcAddress(kernel32dll, "Module32First");
  funModule32Next = (Module32Next_t)
    GetProcAddress(kernel32dll, "Module32Next");


  do {
    if (!funCreateToolhelp32Snapshot || !funModule32First || !funModule32Next) {
      SoDebugError::postWarning("SoAny::listWin32ProcessModules",
                                "Tool Help Library not available (NT4?)");
      break; // goto end of do-while loop
    }
    
    HANDLE tool32snap = funCreateToolhelp32Snapshot(TH32CS_SNAPALL, 0);
    assert((tool32snap != (void *)-1) && "CreateToolhelp32Snapshot() failed");
    
    MODULEENTRY32 moduleentry;
    moduleentry.dwSize = sizeof(MODULEENTRY32);
    ok = funModule32First(tool32snap, &moduleentry);
    assert(ok && "Module32First() failed"); 
    
    SoDebugError::postInfo("SoAny::listWin32ProcessModules",
                           "MODULEENTRY32.szModule=='%s', .szExePath=='%s'",
                           moduleentry.szModule, moduleentry.szExePath);
    
    while (funModule32Next(tool32snap, &moduleentry)) {
      SoDebugError::postInfo("SoAny::listWin32ProcessModules",
                             "MODULEENTRY32.szModule=='%s', .szExePath=='%s'",
                             moduleentry.szModule, moduleentry.szExePath);
    }
    
    assert(GetLastError()==ERROR_NO_MORE_FILES && "Module32Next() failed"); 

    ok = CloseHandle(tool32snap);
    assert(ok && "CloseHandle() failed");
  } while (0);

  ok = FreeLibrary(kernel32dll);
  assert(ok && "FreeLibrary() failed");
}


#else // !HAVE_WIN32_LOADLIBRARY || !HAVE_TLHELP32_H

void
SoAny::listWin32ProcessModules(void)
{
  SoDebugError::postWarning("SoAny::listWin32ProcessModules",
                            "Tool Help Library not available "
                            "(non-win32 platform?)");
}

#endif // !HAVE_WIN32_LOADLIBRARY || !HAVE_TLHELP32_H

/**************************************************************************/

char *
SoAny::strconcat(const char ** stringlist, const char * glue, SbBool glueend) // static
{
  int i;
  size_t gluelen, buflen;
  char * buffer, * ptr;
  assert(stringlist);
  gluelen = 0;
  buflen = 1; // The Terminator (1982)
  if ( glue ) gluelen = strlen(glue);
  for ( i = 0; stringlist[i] != NULL; i++ )
    buflen += strlen(stringlist[i]) + gluelen;
  if ( !glueend ) buflen -= gluelen;
  buffer = new char [buflen];
  assert(buffer);
  ptr = buffer;
  for ( i = 0; stringlist[i] != NULL; i++ ) {
    size_t len;
    len = strlen(stringlist[i]);
    memcpy(ptr, stringlist[i], len);
    ptr += len;
    if ( gluelen && ((stringlist[i+1] != NULL) || glueend) ) {
      memcpy(ptr, glue, gluelen);
      ptr += gluelen;
    }
  }
  *ptr = '\0';
  return buffer;
}

SoNode *
SoAny::loadSceneGraph(const char ** stringlist) // static
{
  char * buffer = SoAny::strconcat(stringlist, "\n");
  SoNode * root = SoAny::loadSceneGraph(buffer);
  delete [] buffer;
  return root;
}

SoNode *
SoAny::loadSceneGraph(char * buffer, unsigned int bufsize) // static
{
  SoSeparator * root;
  SoInput in;
  in.setBuffer(buffer, bufsize ? bufsize : strlen(buffer));
  root = SoDB::readAll(&in);
  return root;
}

SoNode *
SoAny::scanSceneForName(SoNode * scene, const char * name, SbBool searchAll)
{
  assert(scene->getRefCount() > 0);
  SoPath * path;
  if ( SoAny::finder == NULL )
    SoAny::finder = new SoSearchAction;
  SoAny::finder->reset();
  SoAny::finder->setName(SbName(name));
  SoAny::finder->setInterest(SoSearchAction::FIRST);
  if ( searchAll ) SoAny::finder->setSearchingAll(TRUE);
  SoAny::finder->apply(scene);
  path = SoAny::finder->getPath();
  return path ? path->getTail() : NULL;
}

// FIXME: Dummy implementation of sogui_atexit(). Replace with real
// implementation. kintel 20060209
void 
SoAny::atexit(SoAny::atexit_f * fp, int priority)
{
  // disabled this, as it is not safe to clean up SoQt after Coin
  // has been cleaned up. -mortene
  //
  // atexit(fp);
}

static void
soany_atexit_cleanup(void)
{
  struct envvar_data * ptr = envlist_head;
  while (ptr != NULL) {
    struct envvar_data * tmp = ptr;
    free(ptr->name);
    free(ptr->val);
    ptr = ptr->next;
    free(tmp);
  }
  envlist_head = NULL;
  envlist_tail = NULL;

#if defined(HAVE_WIN32_LOADLIBRARY) && defined(HAVE_TLHELP32_H)
  funCreateToolhelp32Snapshot = NULL;
  funModule32First = NULL;
  funModule32Next = NULL;
#endif
}

/**************************************************************************/
