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tshort / Eyeball.jl

Object and type viewer for Julia
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eye fails on VideoReader objects from the VideoIO.jl package #24

Open jonalm opened 2 years ago

jonalm commented 2 years ago

Hi,

I stumbled upon a case where eye fails. Consider this

julia> using Eyeball
julia> using VideoIO
julia> sample_avi_fn = download("https://www.engr.colostate.edu/me/facil/dynamics/files/drop.avi")
julia> handle = VideoIO.openvideo(sample_avi_fn)
julia> eye(handle)
ERROR: type Ptr has no field data
Stacktrace:
  [1] getproperty(x::Ptr{VideoIO.libffmpeg.AVFormatContext}, f::Symbol)
    @ VideoIO.libffmpeg ~/.julia/packages/VideoIO/EsW3Z/lib/libffmpeg.jl:6701
  [2] field_ptr
    @ ~/.julia/packages/VideoIO/EsW3Z/src/util.jl:67 [inlined]
  [3] getproperty
    @ ~/.julia/packages/VideoIO/EsW3Z/src/avptr.jl:44 [inlined]
  [4] (::Eyeball.var"#21#23"{VideoIO.NestedCStruct{VideoIO.libffmpeg.AVFormatContext}})(pn::Symbol)
    @ Eyeball ./none:0
  [5] iterate
    @ ./generator.jl:47 [inlined]
    ....
tshort commented 2 years ago

The following makes me suspect that something's broken with getproperty or with propertynames for a VideoIO.NestedCStruct{VideoIO.libffmpeg.AVCodecContext}. 

julia> dump(handle.codec_context, maxdepth=2)
VideoIO.NestedCStruct{VideoIO.libffmpeg.AVCodecContext}
  data: Base.RefValue{Ptr{VideoIO.libffmpeg.AVCodecContext}}
    x: Ptr{VideoIO.libffmpeg.AVCodecContext} @0x0000000003e90cc0

julia> handle.codec_context.data
ERROR: type Ptr has no field data
Stacktrace:
 [1] getproperty(x::Ptr{VideoIO.libffmpeg.AVCodecContext}, f::Symbol)
   @ VideoIO.libffmpeg ~/.julia/packages/VideoIO/3LUls/lib/libffmpeg.jl:2908
 [2] field_ptr
   @ ~/.julia/packages/VideoIO/3LUls/src/util.jl:67 [inlined]
 [3] getproperty(ap::VideoIO.NestedCStruct{VideoIO.libffmpeg.AVCodecContext}, s::Symbol)
   @ VideoIO ~/.julia/packages/VideoIO/3LUls/src/avptr.jl:44
 [4] top-level scope
   @ REPL[21]:1

julia> propertynames(handle.codec_context)
(:data, :data)

julia> getfield(handle.codec_context, :data)
Base.RefValue{Ptr{VideoIO.libffmpeg.AVCodecContext}}(Ptr{VideoIO.libffmpeg.AVCodecContext} @0x0000000003e90cc0)

julia> getproperty(handle.codec_context, :data)
ERROR: type Ptr has no field data
Stacktrace:
 [1] getproperty(x::Ptr{VideoIO.libffmpeg.AVCodecContext}, f::Symbol)
   @ VideoIO.libffmpeg ~/.julia/packages/VideoIO/3LUls/lib/libffmpeg.jl:2908
 [2] field_ptr
   @ ~/.julia/packages/VideoIO/3LUls/src/util.jl:67 [inlined]
 [3] getproperty(ap::VideoIO.NestedCStruct{VideoIO.libffmpeg.AVCodecContext}, s::Symbol)
   @ VideoIO ~/.julia/packages/VideoIO/3LUls/src/avptr.jl:44
 [4] top-level scope
   @ REPL[24]:1

Maybe I should include a try in there somewhere to catch objects that are broken like this.

jonalm commented 2 years ago

Or maybe fallback to getfield.