Circular source

circular_source.bsh
circular_source

Similar to source_once.bsh source_once, gives an easy way to have two scripts source each other without an infinite loop.

Arguments:

$1 - The file to be sourced if this is the first time.

Output:

Returns 0 if this is the first time, else 1 for already sourced

Internal Use:

  • _VSI_CIRCULAR_SOURCE - State array used on bash 4 or newer

  • _VSI_CIRCULAR_SOURCE_* - State variables used for bash 3.2

In the file that you want to break the infinite loop in, simply:

Example

#!/usr/bin/env bash
source "${VSI_COMMON_DIR}/linux/circular_source.bsh"
circular_source "some_file.bsh" || return 0

In interactive mode, circular_source will still re-source the file, but nominally only once. The return 0 is important so that the rest of the file is not sourced multiple times (usually 2 or 3 times otherwise).

Checks to see if the calling file is used multiple times to perform the current source command. If it is, returns 1 to break the chain.

Note

This doesn’t prevent a script from being sourced more than once ever, only being sourced more than once from within a particular source command.

Warning

circular_source should not be over used because it does execute realpath. While on linux this is a trivial fork, in windows it is a CreateProcess operation which may only takes 33ms, but it only takes 30 calls to equal a second.