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Memory leak when doing an assign operation with a handle

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Quickly summarized, the problem is that when I assign a value from a c++ created object (handle) to a script created one, memory is not freed properly.

The code looks like this:
cBoundingVolume@ pCharBV = GetBoundingVolume();
cBoundingVolume bvCopy = pCharBV;


This does not release the memory of cBoundingVolume (I am not sure of the exact script place the memory allocation takes place but can try and find out if needed) and I get a memory leak.

However,this code works just fine:

cBoundingVolume@ pCharBV = GetBoundingVolume();
cBoundingVolume bvCopy;


GetBoundingVolume is a c++ function and has this declartion:
cBoundingVolume@+ GetBoundingVolume()

I am guessing that the problem might be that I am not declaring the copy operator correctly?
Currently it looks like this:
RegisterOperator("cBoundingVolume &opAssign(const cBoundingVolume &in)", asMETHODPR(cBoundingVolume, operator =, (const cBoundingVolume &), cBoundingVolume &) );
Do I need to do something different for it to work? (as in increasing a user count in cBoundingVolume?)

I was not sure exactly what code is needed, so just say if you need to see more in order to locate the problem!

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I'll look into this. I made some changes in version 2.22.1 to avoid making unnecessary copies with value assignments. It is quite possible that this has broken something.

The opAssign method shouldn't increase the refCount as it only works directly with references and not handles.


The cBoundingVolume is obviously a asOBJ_REF type. Does it have any other flags? Have you registered a copy constructor for it? Does it have a default constructor?

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I wasn't able to reproduce this problem either. It is possible the problem has been fixed in the latest SVN already.

This is the test case I wrote:



engine = asCreateScriptEngine(ANGELSCRIPT_VERSION);
bout.buffer = "";
engine->SetMessageCallback(asMETHOD(CBufferedOutStream, Callback), &bout, asCALL_THISCALL);

asIScriptModule *mod = engine->GetModule("", asGM_ALWAYS_CREATE);
mod->AddScriptSection("script",
"class T { \n"
" T() {} \n"
// " T(int v) {} \n"
" T &opAssign(const T&in o) {return this;} \n"
"} \n"
"T @Get() { return T(); } \n"
"void main() { \n"
" T @t1 = Get(); \n"
" T t2 = t1; \n"
"} \n");

r = mod->Build();
if( r < 0 )
TEST_FAILED;

if( bout.buffer != "" )
{
printf("%s", bout.buffer.c_str());
TEST_FAILED;
}

r = ExecuteString(engine, "main()", mod);
if( r != asEXECUTION_FINISHED )
TEST_FAILED;

engine->Release();


The main() function in the script produces the following bytecode:



void main()

Temps: 2

Variables:
001: T@ t1
003: T t2
002: T {noname}


0 0 * PUSH 3
- 7,3 -
1 3 * SUSPEND
2 3 * VarDecl 0
2 3 * CALL 34 (T@ Get())
4 3 * STOREOBJ v2
5 3 * PshVPtr v2
6 4 * PSF v1
7 5 * REFCPY 0xc9cde8
9 4 * FREE v2, 13225448
11 4 * POP 1
- 8,3 -
12 3 * SUSPEND
13 3 * VarDecl 1
13 3 * ChkNullV v1
14 3 * VAR v1
15 4 * CALL 32 (T@ T())
17 4 * STOREOBJ v3
18 4 * PshVPtr v3
19 5 * GETOBJREF 1
20 5 * CALLINTF 36 (T& T::opAssign(const T&in))
- 9,2 -
22 3 * SUSPEND
23 3 * FREE v3, 13225448
25 3 * FREE v1, 13225448
27 3 * 0:
27 3 * RET 0


Can you show me the bytecode that is produced by your script? It should be similar to the above. If you use the debug version of the scripting library it will write a file with the bytecode for each compiled function in the directory AS_DEBUG.

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I only use [color=#282828][font=helvetica, arial, verdana, tahoma, sans-serif]

asOBJ_REF as flag.

[/font]

[color=#282828][font=helvetica, arial, verdana, tahoma, sans-serif]

Here are the factories:

[/font]
[color=#282828][font=helvetica, arial, verdana, tahoma, sans-serif]

[/font]RegisterFactory("", Factory_cBoundingVolume_Default);
RegisterFactory("const cVector3f &in avMin, const cVector3f &in avMax", Factory_cBoundingVolume_MinMax);
RegisterFactory("const cVector3f &in avSize", Factory_cBoundingVolume_Size);


Here is the script:
void main()
{
cBoundingVolume @pBV = GetBV();
cBoundingVolume copyBV = pBV;

Print("Done!\n");
}


Here is the bytecode output:

void main()

Temps: 2, 10

Variables:
001: cBoundingVolume@ pBV
003: cBoundingVolume copyBV
002: cBoundingVolume {noname}
010: tString {noname}


0 0 * PUSH 10
- 3,2 -
1 10 * SUSPEND
2 10 * VarDecl 0
2 10 * CALLSYS 4125 (cBoundingVolume@ GetBV())
4 10 * STOREOBJ v2
5 10 * PshVPtr v2
6 11 * PSF v1
7 12 * REFCPY 0x3dc6598
9 11 * FREE v2, 64775576
11 11 * POP 1
- 4,2 -
12 10 * SUSPEND
13 10 * VarDecl 1
13 10 * ChkNullV v1
14 10 * VAR v1
15 11 * CALLSYS 218 (cBoundingVolume@ _beh_2_())
17 11 * STOREOBJ v3
18 11 * PshVPtr v3
19 12 * GETOBJREF 1
20 12 * CALLSYS 227 (cBoundingVolume& cBoundingVolume::opAssign(const cBoundingVolume&in))
- 6,2 -
22 10 * SUSPEND
23 10 * STR 0 (l:6 s:"Done!
")
24 12 * PSF v10
25 13 * CALLSYS 351 (tString _string_factory_(const int, const uint8&))
27 10 * ObjInfo v10, 1
27 10 * PSF v10
28 11 * CALLSYS 4123 (void Print(tString&in))
30 10 * PSF v10
31 11 * CALLSYS 343 (void tString::_beh_1_())
- 7,2 -
33 10 * ObjInfo v10, 0
33 10 * SUSPEND
34 10 * FREE v3, 64775576
36 10 * FREE v1, 64775576
38 10 * 0:
38 10 * RET 0

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The bytecode produced looks ok. It is freeing the objects properly.

I think the problem might be in your implementation of the opAssign method.

Are you by any chance copying the ref counter too? That mustn't be done as it would screw up the memory management.

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Late reply


Are you by any chance copying the ref counter too? That mustn't be done as it would screw up the memory management.


Ah yes! That was the problem! Thanks!

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