uber
Generator directory traversal speed is slow
First, thank you for the wonderful DI framework!
I've found that just traversing the input directory is quite slow. To prove this, I ran the following command, which excluded all files it came across (because the project is in a directory called Development... which seems like a bug since exclusion paths should only consider paths from the working directory 🤷♂):
time Carthage/Checkouts/Needle/Generator/bin/needle generate App/Sources/Generated/Needle.swift . --exclude-paths /Development/
The output for our current project, which has about 8600 files, is about a second.
When only excluding what we need to the time is around 4 seconds.
I know this can be faster, since for the time being we are instead invoking ag (https://github.com/ggreer/the_silver_searcher) to find all files with import NeedleFoundation and then using those files as the input:
time ag --depth -1 --group -l "import NeedleFoundation" > App/Sources/Generated/NeedleSourceList.txt
This takes about 0.25 seconds and then the following takes about 0.08 seconds (since the source list is only 8 files):
time Carthage/Checkouts/Needle/Generator/bin/needle generate App/Sources/Generated/Needle.swift App/Sources/Generated/NeedleSourceList.txt
In summary, by using an external program to generate the source file list we make the generation process at least an order of magnitude faster.
