Fix get_file_size behavior inconsistency for folders #561
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Different OSes have different behavior when trying to fopen/fseek/ftell a folder. On Linux, some systems return 0 size, some systems return an error, and some systems return LONG_MAX. LONG_MAX is particularly problematic because that causes spurious OOMs under address sanitizer. Using fstat manually cleans this up, however it introduces a new dependency on platform specific headers that we didn't have before, and also has unclear behavior on 64-bit systems wrt 32-bit sizes which will need to be tested further as I'm not certain if the behavior needs to be special-cased only for MSVC/MinGW, which are currently not handled by this path (unless MinGW defines __unix__...)
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The same approach works on MSVC but is a little bit higher overhead compared to fseek/ftell we use right now, so MSVC will have to stick with fseek/ftell (and it requires special handling for large offsets anyhow, as fstat in MSVC also uses 32-bit sizes). |
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Different OSes have different behavior when trying to fopen/fseek/ftell a folder. On Linux, some systems return 0 size, some systems return an error, and some systems return LONG_MAX. LONG_MAX is particularly problematic because that causes spurious OOMs under address sanitizer.
Using fstat manually cleans this up, however it introduces a new dependency on platform specific headers that we didn't have before, and also has unclear behavior on 64-bit systems wrt 32-bit sizes which will need to be tested further as I'm not certain if the behavior needs to be special-cased only for MSVC/MinGW, which are currently not handled by this path (unless MinGW defines unix...)
Fixes #560.