complicated bug in ltn12.filter.chain...

src/ltn12.lua

@@ -34,8 +34,23 @@ end
 local function chain2(f1, f2)
     if type(f1) ~= 'function' then error('invalid filter', 2) end 
     if type(f2) ~= 'function' then error('invalid filter', 2) end 
+    local co = coroutine.create(function(chunk)
+        while true do
+            local filtered1 = f1(chunk)
+            local filtered2 = f2(filtered1)
+            local done2 = filtered1 and ""
+            while true do
+                if filtered2 == "" or filtered2 == nil then break end
+                coroutine.yield(filtered2)
+                filtered2 = f2(done2)
+            end
+            if filtered1 == "" then chunk = coroutine.yield(filtered1)
+            elseif filtered1 == nil then return nil
+            else chunk = chunk and "" end
+        end
+    end)
     return function(chunk)
-        return f2(f1(chunk))
+        return shift(coroutine.resume(co, chunk))
     end
 end
 

test/mimetest.lua

@@ -34,11 +34,52 @@ local mao = [[
 local function random(handle, io_err)
     if handle then
         return function()
-            local chunk = handle:read(math.random(0, 1024))
+            local len = math.random(0, 1024)
+            local chunk = handle:read(len)
             if not chunk then handle:close() end
             return chunk
         end
-    else source.empty(io_err or "unable to open file") end
+    else return ltn12.source.empty(io_err or "unable to open file") end
+end
+
+local function format(chunk)
+    if chunk then
+        if chunk == "" then return "''"
+        else return string.len(chunk) end
+    else return "nil" end
+end
+
+local function show(name, input, output)
+    local sin = format(input)
+    local sout = format(output)
+    io.write(name, ": ", sin, " -> ", sout, "\n")
+end
+
+local function chunked(length)
+    local tmp
+    return function(chunk)
+        local ret
+        if chunk and chunk ~= "" then
+            tmp = chunk
+        end
+        ret = string.sub(tmp, 1, length)
+        tmp = string.sub(tmp, length+1)
+        if not chunk and ret == "" then ret = nil end
+        return ret
+    end
+end
+
+--[[
+local function named(f, name)
+    return function(chunk)
+        local ret = f(chunk)
+        show(name, chunk, ret)
+        return ret
+    end
+end
+]]
+local function named(f)
+    return f
 end
 
 local what = nil
@@ -153,11 +194,11 @@ local function encode_b64test()
 end
 
 local function decode_b64test()
-    local d1 = mime.decode("base64")
+    local d1 = named(mime.decode("base64"), "d1")
-    local d2 = mime.decode("base64")
+    local d2 = named(mime.decode("base64"), "d2")
-    local d3 = mime.decode("base64")
+    local d3 = named(mime.decode("base64"), "d3")
-    local d4 = mime.decode("base64")
+    local d4 = named(mime.decode("base64"), "d4")
-    local chain = ltn12.filter.chain(d1, d2, d3, d4)
+    local chain = named(ltn12.filter.chain(d1, d2, d3, d4), "chain")
     transform(eb64test, db64test, chain)
 end
 

test/testsupport.lua

@@ -1,5 +1,5 @@
 function readfile(name)
-	local f = io.open(name, "r")
+	local f = io.open(name, "rb")
 	if not f then return nil end
 	local s = f:read("*a")
 	f:close()