Re: [Podofo-users] Base 14 fonts are not thread-safe

[Michal S. <sud...@gm...>]

Discard previous diff. I hope final fix but someone should check it.


On Fri, Nov 16, 2018 at 6:17 PM Michal Sudolsky <sud...@gm...> wrote:

> One thing I forgot. PODOFO_Base14FontDef_FindBuiltinData is used on places
> where return value is not deallocated. This would cause memory leaks. I am
> sending better patch.
>
> Metrics object is allocated and copy constructed from global only on
> places where it will be eventually deallocated.
>
> Still is good idea to have PODOFO_BUILTIN_FONTS const and
> PODOFO_Base14FontDef_FindBuiltinData to return const pointer.
>
>
> On Fri, Nov 16, 2018 at 5:56 PM Michal Sudolsky <sud...@gm...>
> wrote:
>
>> Fonts created for different documents should be independent. In other
>> case you cannot do anything usable with them when using multiple threads.
>>
>> Code:
>> ``` c++
>> PdfMemDocument doc0;
>> PdfFont *font0 = doc0.CreateFont("Helvetica");
>> font0->SetFontSize(10);
>>
>> PdfMemDocument doc1;
>> PdfFont *font1 = doc1.CreateFont("Helvetica");
>> font1->SetFontSize(20);
>>
>> printf("font0 size %g\n", font0->GetFontSize());
>> printf("font1 size %g\n", font1->GetFontSize());
>> ```
>>
>> Output:
>> ```
>> font0 size 20
>> font1 size 20
>> ```
>>
>> What I would expect (or what happens when is font for example "Arial"):
>> ```
>> font0 size 10
>> font1 size 20
>> ```
>>
>> Fonts font0 and font1 are different objects but they share same
>> m_pMetrics (in case of base 14 fonts) which is used for font size and other
>> font settings. This is because PODOFO_Base14FontDef_FindBuiltinData is
>> returning mutable pointer to static global array PODOFO_BUILTIN_FONTS.
>>
>> This is here probably from beginning.
>>
>> I am sending patch. Hopefully I did not forget something.
>> PODOFO_Base14FontDef_FindBuiltinData is now returning newly allocated
>> metrics object copy constructed from PODOFO_BUILTIN_FONTS[i]. I deleted
>> destructor of PdfFontTypeBase14 so metrics object is properly deleted with
>> font. I also changed PODOFO_BUILTIN_FONTS to const for sure that there is
>> nothing else that changes it.
>>
>>