[Old] Background Transfer Manager slow to react for inaccessible URLs

[Flint]

1. Create a list file with several URLs (better 10 or more) which cannot be accessed by TC. I've noticed this behavior when trying to download old TC versions from this post — for some reason, TC refuses to download from there (I'm not sure why; that's probably a subject for a separate report).

Sample list file

Code: Select all

https://madsenworld.dk/tcmd/finals/tcmd900ax32.exe
https://madsenworld.dk/tcmd/finals/tcmd900ax32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd900ax64.exe
https://madsenworld.dk/tcmd/finals/tcmd900x32.exe
https://madsenworld.dk/tcmd/finals/tcmd900x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd900x64.exe
https://madsenworld.dk/tcmd/finals/tcmd910x32.exe
https://madsenworld.dk/tcmd/finals/tcmd910x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd910x64.exe
https://madsenworld.dk/tcmd/finals/tcmd912x32.exe
https://madsenworld.dk/tcmd/finals/tcmd912x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd912x64.exe
https://madsenworld.dk/tcmd/finals/tcmd920x32.exe
https://madsenworld.dk/tcmd/finals/tcmd920x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd920x64.exe
https://madsenworld.dk/tcmd/finals/tcmd921ax32.exe
https://madsenworld.dk/tcmd/finals/tcmd921ax32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd921ax64.exe
https://madsenworld.dk/tcmd/finals/tcmd921x32.exe
https://madsenworld.dk/tcmd/finals/tcmd921x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd921x64.exe
https://madsenworld.dk/tcmd/finals/tcmd922ax32.exe
https://madsenworld.dk/tcmd/finals/tcmd922ax32_64-2.exe
https://madsenworld.dk/tcmd/finals/tcmd922ax32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd922ax64-2.exe
https://madsenworld.dk/tcmd/finals/tcmd922ax64.exe
https://madsenworld.dk/tcmd/finals/tcmd922x32.exe
https://madsenworld.dk/tcmd/finals/tcmd922x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd922x64.exe
https://madsenworld.dk/tcmd/finals/tcmd950x32.exe
https://madsenworld.dk/tcmd/finals/tcmd950x32_64.exe
https://madsenworld.dk/tcmd/finals/tcmd950x64.exe

2. Run Net -> FTP Download from list, specify this list file, confirm downloading.
3. The Background Transfer Manager window opens and begins to download the entries, each taking about 1-2 seconds to try, fail and switch to the next URL. While it's going on, try to interact with the BTM window.
4. Every action takes really long time to even be noticed by TC, let alone be processed. For example, I click the Pause button, and about 15 seconds pass before TC reacts to this and finally pauses the operation (in the meantime several entries are tried and failed, which I might have wanted to exclude).

In some of my experiments I have not even been able to do anything with this dialog, at all! On any of my action the dialog first does nothing, then freezes, goes into "Window not responding" mode, then after a couple of seconds unlocks, but my previous action is already discarded, so TC just continues to do what it was doing. I try to press a button again, the dialog freezes again, and so on. I even had to kill it by exiting the main TC window, because neither Pause, not the [X] close button of the BTM window worked for me. In further experiments, it didn't quite reach such an extreme condition, but even then this behavior is very annoying.

Similar issues have been posted many times (as I remember, they are caused by having UI processed in the same thread as downloading), and for local files they've been more or less worked around. But for slow Internet downloads, it looks like the problem is still there.

Tested in Win7 x64, TC 9.51rc4, 9.22a, 32- and 64-bit.

[ghisler(Author)]

Hmm, no idea - I will check it in the debugger.