Fix position of underlying stream when sharing buffers (#222)

fuzz/fuzz.jl

@@ -91,15 +91,41 @@ read_methods = Data.SampledFrom([
     end
 ])
 
+# Return true if the stats of a stream are self consistent
+# This function assumes stream was never seeked.
+function is_stats_consistent(stream)
+    if stream isa TranscodingStream
+        s = TranscodingStreams.stats(stream)
+        inner_pos = position(stream.stream)
+        pos = position(stream)
+        # event!("stats(stream)", s)
+        # event!("position(stream.stream)", inner_pos)
+        # event!("position(stream)", pos)
+        if isreadable(stream)
+            s.out == pos || return false
+            s.in == inner_pos || return false
+        else
+            iswritable(stream) || return false
+            s.in == pos || return false
+            s.out == inner_pos || return false
+        end
+        s.transcoded_in ≤ s.in || return false
+        s.transcoded_out ≥ s.out || return false
+    end
+    true
+end
 
 @check function read_byte_data(
         kws=read_codecs_kws,
         data=datas,
     )
     stream = wrap_stream(kws, IOBuffer(data))
-    for i in eachindex(data)
+    for i in 1:length(data)
+        position(stream) == i-1 || return false
+        is_stats_consistent(stream) || return false
         read(stream, UInt8) == data[i] || return false
     end
+    is_stats_consistent(stream) || return false
     eof(stream)
 end
 @check function read_data(
@@ -108,6 +134,7 @@ end
     )
     stream = wrap_stream(kws, IOBuffer(data))
     read(stream) == data || return false
+    is_stats_consistent(stream) || return false
     eof(stream)
 end
 @check function read_data_methods(
@@ -122,13 +149,15 @@ end
         append!(x, d)
         length(x) == position(stream) || return false
     end
+    is_stats_consistent(stream) || return false
     x == data[eachindex(x)]
 end
 
 # flush all nested streams and return final data
 function take_all(stream)
     if stream isa Base.GenericIOBuffer
-        take!(stream)
+        seekstart(stream)
+        read(stream)
     else
         write(stream, TranscodingStreams.TOKEN_END)
         flush(stream)
@@ -144,7 +173,9 @@ const write_codecs_kws = map(reverse, read_codecs_kws)
     )
     stream = wrap_stream(kws, IOBuffer())
     write(stream, data) == length(data) || return false
-    take_all(stream) == data
+    take_all(stream) == data || return false
+    is_stats_consistent(stream) || return false
+    true
 end
 @check function write_byte_data(
         kws=write_codecs_kws,
@@ -153,24 +184,10 @@ end
     stream = wrap_stream(kws, IOBuffer())
     for i in 1:length(data)
         position(stream) == i-1 || return false
-        if stream isa TranscodingStream
-            s = TranscodingStreams.stats(stream)
-            s.in == i-1 || return false
-            # TODO fix position(stream.stream)
-            # s.out == position(stream.stream) || return false
-            # s.transcoded_in == s.out || return false
-            # s.transcoded_out == s.out || return false
-        end
+        is_stats_consistent(stream) || return false
         write(stream, data[i]) == 1 || return false
     end
     take_all(stream) == data || return false
-    if stream isa TranscodingStream
-        s = TranscodingStreams.stats(stream)
-        s.in == length(data) || return false
-        # TODO fix position(stream.stream)
-        # s.out == position(stream.stream) || return false
-        # s.transcoded_in == s.out || return false
-        # s.transcoded_out == s.out || return false
-    end
+    is_stats_consistent(stream) || return false
     true
 end

src/noop.jl

@@ -155,8 +155,12 @@ function stats(stream::NoopStream)
     if mode === :idle
         in = out = 0
     elseif mode === :read
-        in = buffer.transcoded
-        out = in - buffersize(buffer)
+        out = buffer.transcoded - buffersize(buffer)
+        if has_sharedbuf(stream)
+            in = out
+        else
+            in = buffer.transcoded
+        end
     elseif mode === :write
         out = stream.state.bytes_written_out
         in = out

src/stream.jl

@@ -605,10 +605,15 @@ function stats(stream::TranscodingStream)
     if mode === :idle
         transcoded_in = transcoded_out = in = out = 0
     elseif mode === :read || mode === :stop
-        transcoded_in = buffer2.transcoded
         transcoded_out = buffer1.transcoded
-        in = transcoded_in + buffersize(buffer2)
         out = transcoded_out - buffersize(buffer1)
+        if has_sharedbuf(stream)
+            transcoded_in = stats(stream.stream).out
+            in = transcoded_in
+        else
+            transcoded_in = buffer2.transcoded
+            in = transcoded_in + buffersize(buffer2)
+        end
     elseif mode === :write
         transcoded_in = buffer1.transcoded
         out = state.bytes_written_out
@@ -709,8 +714,12 @@ function callprocess(stream::TranscodingStream, inbuf::Buffer, outbuf::Buffer)
         input_delta = Δin,
         output_delta = Δout,
     )
-    consumed!(inbuf, Δin, transcode = true)
-    supplied!(outbuf, Δout, transcode = true)
+    consumed!(inbuf, Δin;
+        transcode = !has_sharedbuf(stream) || stream.state.mode === :write,
+    ) # inbuf is buffer1 if mode is :write
+    supplied!(outbuf, Δout;
+        transcode = !has_sharedbuf(stream) || stream.state.mode !== :write,
+    ) # outbuf is buffer1 if mode is not :write
     if has_sharedbuf(stream)
         if stream.state.mode === :write
             # this must be updated before throwing any error if outbuf is shared.

test/codecdoubleframe.jl

@@ -324,8 +324,8 @@ DoubleFrameDecoderStream(stream::IO; kwargs...) = TranscodingStream(DoubleFrameD
             @test stat.out == 0
             read(stream)
             stat = TranscodingStreams.stats(stream)
-            @test_broken stat.in == 16
-            @test_broken stat.transcoded_in == 16
+            @test stat.in == 16
+            @test stat.transcoded_in == 16
             @test stat.transcoded_out == 6
             @test stat.out == 6
             close(stream)
@@ -373,7 +373,7 @@ DoubleFrameDecoderStream(stream::IO; kwargs...) = TranscodingStream(DoubleFrameD
             @test stat.transcoded_in == 16
             @test stat.transcoded_out == 6
             @test stat.out == 6
-            @test_broken position(stream.stream) == 6
+            @test position(stream.stream) == 6
             close(stream)
         end
     end

test/codecnoop.jl

@@ -193,7 +193,7 @@ using FillArrays: Zeros
         @test stat.out === Int64(0)
         eof(stream)
         stat = TranscodingStreams.stats(stream)
-        @test_broken stat.in === Int64(0)
+        @test stat.in === Int64(0)
         @test stat.out === Int64(0)
         read(stream)
         stat = TranscodingStreams.stats(stream)