kc3-lang/freetype/src

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  • Hash : 5d27b10f
    Author : Oleg Oshmyan
    Date : 2021-07-13T10:59:32

    [base] Fix `FT_Open_Face`'s handling of user-supplied streams. This was already true (though undocumented) most of the time, but not if `FT_NEW` inside `FT_Stream_New` failed or if the `FT_OPEN_XXX` flags were bad. Normally, `FT_Open_Face` calls `FT_Stream_New`, which returns the user-supplied stream unchanged, and in case of any subsequent error in `FT_Open_Face`, the stream is closed via `FT_Stream_Free`. Up to now, however, `FT_Stream_New` allocates a new stream even if it is already given one by the user. If this allocation fails, the user-supplied stream is not returned to `FT_Open_Face` and never closed. Moreover, the user cannot detect this situation: all they see is that `FT_Open_Face` returns `FT_Err_Out_Of_Memory`, but that can also happen after a different allocation fails within the main body of `FT_Open_Face`, when the user's stream has already been closed by `FT_Open_Face`. It is plausible that the user stream's `close` method frees memory allocated for the stream object itself, so the user cannot defensively free it upon `FT_Open_Face` failure lest it ends up doubly freed. All in all, this ends up leaking the memory/resources used by user's stream. Furthermore, `FT_Stream_New` simply returns an error if the `FT_OPEN_XXX` flags are unsupported, which can mean either an invalid combination of flags or a perfectly innocent `FT_OPEN_STREAM` on a FreeType build that lacks stream support. With this patch, the user-supplied stream is closed even in these cases, so the user can be sure that if `FT_Open_Face` failed, the stream is definitely closed. * src/base/ftobjs.c (FT_Stream_New): Don't allocate a buffer unnecessarily. Move error-handling code to make the control flow more obvious. Close user-supplied stream if the flags are unsupported. `FT_Stream_Open` always sets `pathname.pointer`, so remove the redundant (re)assignment. None of the `FT_Stream_Open...` functions uses `stream->memory`, so keep just one assignment at the end, shared among all possible control flow paths. ('Unsupported flags' that may need a stream closure can be either an invalid combination of multiple `FT_OPEN_XXX` mode flags or a clean `FT_OPEN_STREAM` flag on a FreeType build that lacks stream support.)

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