Hi John,
Reviewing the fix, it strikes me that the code should probably be
something like:
ShapeAttribute::ShapeAttribute(const char * name, const char * value) :
_name(name),
_type(STRING)
{
if (value) _string = strdup(value);
else // some kind of fallback
}
A null name would also be potential problem for the ShapeAttribute code.
Thoughts?
Robert.
On Thu, Jun 12, 2008 at 3:59 PM, John Vidar Larring
<[EMAIL PROTECTED]> wrote:
> Hi All,
>
> Short version:
> --------------
>
> Problem: Empty string value in an osgSim::ShapeAttributeList causes SIGSEV
> when loading a .osg file.
>
> Solution: Changing line 47 in src/osgSim/ShapeAttribute.cpp from:
> - std::string str(value);
> + std::string str((value ? value : ""));
>
> Attached file is a modification of src/osgSim/ShapeAttribute.cpp in svn
> revision 8426.
>
> Long version (including context):
> ---------------------------------
>
> osgGIS now allows the user to keep meta-data when converting ESRI Shape
> files to OSG graph:
>
> osggis: world.shp -> world.osg:
> [...snip...]
> Geode {
> UserData {
> osgSim::ShapeAttributeList {
> string "cntry_name" "Antarctica"
> int "colormap" 7
> string "curr_code" "NCIC"
> string "curr_type" ""
> string "fips_cntry" "AY"
> string "gmi_cntry" "ATA"
> string "iso_2digit" "AQ"
> string "iso_3digit" "ATA"
> string "landlocked" "N"
> string "long_name" "Antarctica"
> int "pop_cntry" -99999
> string "sovereign" "Antarctica"
> double "sqkm" 1.23031e+07
> double "sqmi" 4.75021e+06
> }
> }
> [...snip...]
>
> ...which is parallell to what 'osgconv world.shp world.osg' produces:
> [...snip...]
> Geometry {
> DataVariance STATIC
> UserData {
> osgSim::ShapeAttributeList {
> string "FIPS_CNTRY" "AY"
> string "GMI_CNTRY" "ATA"
> string "ISO_2DIGIT" "AQ"
> string "ISO_3DIGIT" "ATA"
> string "CNTRY_NAME" "Antarctica
>
> "
> string "LONG_NAME" "Antarctica "
> string "SOVEREIGN" "Antarctica "
> int "POP_CNTRY" -99999
> string "CURR_TYPE" " "
> string "CURR_CODE" "NCIC"
> string "LANDLOCKED" "N"
> int "SQKM" 12303052
> int "SQMI" 4750207
> int "COLORMAP" 7
> }
> }
> [...snip...]
>
> The difference is that osgconv (a.k.a. shp plugin) adds whitespace to string
> "curr_type" while osggis does not. However, the output from osggis is
> cleaner and should IMHO be acceptable.
>
> However, osgDB::Input in ShapeAttributeList_readLocalData converts the empty
> string to a NULL pointer:
>
> bool ShapeAttributeList_readLocalData(osg::Object &obj, osgDB::Input &fr)
> {
> bool iteratorAdvanced = false;
> ShapeAttributeList &sal = static_cast<ShapeAttributeList &>(obj);
>
> int entry = fr[0].getNoNestedBrackets();
>
> while (!fr.eof() && fr[0].getNoNestedBrackets()>=entry)
> {
> if (fr.matchSequence("string %s %s"))
> {
> sal.push_back(osgSim::ShapeAttribute(fr[1].getStr(),
> fr[2].getStr())); <<== fr[2].getStr() returns NULL for 'string "curr_type"
> ""'
> fr += 3;
> iteratorAdvanced = true;
> }
> [...snip...]
>
> This results in a SIGSEV in ShapeAttribute::ShapeAttribute(const char *
> name, const char * value) with the following stack trace:
>
> #0 0x00000030a032e25d in raise () from /lib64/tls/libc.so.6
> #1 0x00000030a032fa5e in abort () from /lib64/tls/libc.so.6
> #2 0x00000030a28b1148 in __gnu_cxx::__verbose_terminate_handler () from
> /usr/lib64/libstdc++.so.6
> #3 0x00000030a28af176 in __cxa_call_unexpected () from
> /usr/lib64/libstdc++.so.6
> #4 0x00000030a28af1a3 in std::terminate () from /usr/lib64/libstdc++.so.6
> #5 0x00000030a28af2a3 in __cxa_throw () from /usr/lib64/libstdc++.so.6
> #6 0x00000030a2851bf0 in std::__throw_logic_error () from
> /usr/lib64/libstdc++.so.6
> #7 0x00000030a2892706 in std::basic_string<char, std::char_traits<char>,
> std::allocator<char> >::basic_string$base () from /usr/lib64/libstdc++.so.6
> #8 0x00000030a28927b3 in std::basic_string<char, std::char_traits<char>,
> std::allocator<char> >::basic_string () from /usr/lib64/libstdc++.so.6
> #9 0x0000002a96c9c2d7 in osgSim::ShapeAttribute::ShapeAttribute () at
> /usr/lib/gcc/x86_64-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/locale_facets.tcc:2443
> #10 0x0000002a98083d16 in ShapeAttributeList_readLocalData ([EMAIL PROTECTED],
> [EMAIL PROTECTED]) at
> /home/john/external.el4/OpenSceneGraph/trunk/src/osgPlugins/osgSim/IO_ShapeAttribute.cpp:38
> #11 0x0000002a95cab5b0 in osgDB::Registry::readObject (this=0x51ac90,
> [EMAIL PROTECTED], [EMAIL PROTECTED]) at
> /home/john/external.el4/OpenSceneGraph/trunk/src/osgDB/Registry.cpp:1003
> #12 0x0000002a95cab78a in osgDB::Registry::readObject (this=0x51ac90,
> [EMAIL PROTECTED]) at
> /home/john/external.el4/OpenSceneGraph/trunk/src/osgDB/Registry.cpp:1036
>
> The attached file fixes the problem by testing for NULL pointer value in
> ShapeAttribute::ShapeAttribute.
>
> Best regards,
> John
>
> --
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