Do not extract embedded app on every execution

[pierredup]

When embedding a large app (in my case around ~700mb), the app checksum is calculated and the tar is extracted on every execution of the binary.

This slows down the execution (running php-cli takes around ~8 seconds) since this process needs to run every time. Instead, we can extract the app only once and re-use the same files for every execution.

Another drawback of the current process, is that when the web-server is running (using php-server), and you want to run a cli command, then it would remove and re-extract the tar while the webserver is still running.

The PR adds the following changes:

• Calculate the checksum at build-time instead of runtime, and embed the checksum in the binary
• Only untar the archive if it doesn't exist already on the filesystem

[dunglas]

Good idea!

Could we also try to cleanup outdated directories after an upgrade?

[pierredup]

Could we also try to cleanup outdated directories after an upgrade?

The directory name should probably then also contain the app name (or some other unique identifier). If we just clear all the frankenphp_* folders in the temp directory, then we might clear the files of a different FrankenPHP app.

[dunglas]

Ok, it's more complex. Let's let the OS do the cleanup for now.

[dunglas]

Thank you!