Re: [gentoo-dev] new eclass: tmpfiles.eclass round 4
On Wed, Nov 30, 2016 at 8:35 PM, Mike Gilbertwrote: > On Wed, Nov 30, 2016 at 7:11 AM, konsolebox wrote: I also prefer some things this way: - Indent the contents of the first `if` block for consistency's sake, and less confusion. >>> >>> I disagree; indenting the entire eclass is silly and does not really >>> improve readability. Also, this is a very common pattern found in >>> other eclasses. >> >> I prefer following consistency before anything else. And it's just >> uncommon and odd, but it's not silly. Imagine if you use another `if` >> block on the second level where more functions are defined. Would you >> also not indent that? > > That first "if" is a bit of a special case; it's only there to prevent > the code from being executed more than once in global scope. This > provides a minor speed boost when the eclass gets sourced more than > once, and makes sure that any global variables are only set once. OT: inherit() should have already been able to have a non-hacky solution of making sure that eclass files are loaded only once. Bash 4.2 has already supported global declaration of variables with -g (in case the flag variable would need to be declared inside a function), and associative arrays with -A. Even older versions of Bash (<4.0) can make use of multiple variables with a common prefix to imitate associative arrays if compatibility is needed. It could just check BASH_VERSINFO if it has to downgrade to a less-efficient method. Besides no longer having to rely on a special `if` block, it probably would also make loading of ebuilds faster since script codes that are referenced multiple times wouldn't have to be re-parsed again and again by bash. It's scary to imagine how it happens in all ebuilds that's read in portage, but maybe repeated loading of eclass files doesn't always happen, who knows. (I think it's still significant even if the dependencies are already cached.) > I think of it as being similar to pre-processor statement you would > find in a C header file; one does not generally indent all the code > within a C header file, because it just introduces a big chunk of > whitespace that does not improve code readability. I did as well, but I'll still prefer to have it indented, because it avoids trying to know what the last lone `fi` is for, if you haven't seen the first `if` condition yet. If they are indented, your mind is automatically set to know that they are within a conditional block, and no surprise happens. Maybe that's not the case if people are already used to seeing those setup, like in eclass files, but I'm not, so it does help improve readability in my case. To be honest I find it painful to see anything inside a block to be not indented, no matter what the reason is. You can say that they look like preprocessors in C, and preprocessors don't make codes indent, but preprocessors are not (functional) codes, and they are naturally recognized to have their own "indentation space" or patterns, unlike the shell's `if`. But anyway, I think I find it understandable now, in the context of eclass files. -- konsolebox
Re: [gentoo-dev] new eclass: tmpfiles.eclass round 4
On Wed, Nov 30, 2016 at 7:11 AM, konsoleboxwrote: >>> I also prefer some things this way: >>> >>> - Indent the contents of the first `if` block for consistency's sake, >>> and less confusion. >> >> I disagree; indenting the entire eclass is silly and does not really >> improve readability. Also, this is a very common pattern found in >> other eclasses. > > I prefer following consistency before anything else. And it's just > uncommon and odd, but it's not silly. Imagine if you use another `if` > block on the second level where more functions are defined. Would you > also not indent that? That first "if" is a bit of a special case; it's only there to prevent the code from being executed more than once in global scope. This provides a minor speed boost when the eclass gets sourced more than once, and makes sure that any global variables are only set once. I think of it as being similar to pre-processor statement you would find in a C header file; one does not generally indent all the code within a C header file, because it just introduces a big chunk of whitespace that does not improve code readability.
Re: [gentoo-dev] new eclass: tmpfiles.eclass round 4
On 11/30/16, Mike Gilbertwrote: > On Wed, Nov 30, 2016 at 3:38 AM, konsolebox wrote: >> - `[[ ${ROOT} == / ]] || return 0` seems to present a harmless false >> condition, and it doesn't show an error message. I would be helpful >> to have a comment added above it to give details why. > > We only want to process tmpfiles for the currently running system. > > If ROOT is not /, it indicates we are installing the package for use > on a different system or in a container. In either case, the tmpfiles > would be processed upon boot when that system/container is started. > > I find this fairly obvious, but if William wants to document it that's > fine. I'm not familiar with that, and so would other scripters who would look at the eclass. >> I also prefer some things this way: >> >> - Indent the contents of the first `if` block for consistency's sake, >> and less confusion. > > I disagree; indenting the entire eclass is silly and does not really > improve readability. Also, this is a very common pattern found in > other eclasses. I prefer following consistency before anything else. And it's just uncommon and odd, but it's not silly. Imagine if you use another `if` block on the second level where more functions are defined. Would you also not indent that? >> - Patterns in the `case` block doesn't have to be indented. This makes >> the contents of the `case` block aligned with the contents of the >> other blocks (`if`, `while`, etc.), and it makes the use of indents at >> minimum when the block is used recursively. > > Sorry, I have no idea what you're trying to say here. Recursive blocks? One expensive in the use of indents: case $x in a) # first inner level case $y in 1) # second inner level case ... ;; 2) ;; esac ;; b) ;; esac if [ "$x" = a ]; then # first inner level if [ "$y" = 1 ]; then # second inner level elif [ "$y" = 2 ]; then : else : fi elif [ "$x" = b ]; then : else : fi vs. case $x in a) case $y in 1) case ... ;; 2) ;; esac ;; b) ;; esac > This really feels like you're making a personal style suggestion here, > and I personally see nothing wrong with it as-is. Yes the second part is more personal. -- konsolebox
Re: [gentoo-dev] new eclass: tmpfiles.eclass round 4
On Wed, Nov 30, 2016 at 3:38 AM, konsoleboxwrote: > There are some things I noticed in the tmpfiles_process() function: > > - `type` currently also checks for functions, alias, and builtins, > besides executable files. If that's not intended, the `-P` option > should be added. I cannot conceive of any way a function or alias would be defined with these names unless an ebuild author did it intentionally or a user did it via /etc/portage/bashrc. In either case, I see no need to prevent that. > - `[[ ${ROOT} == / ]] || return 0` seems to present a harmless false > condition, and it doesn't show an error message. I would be helpful > to have a comment added above it to give details why. We only want to process tmpfiles for the currently running system. If ROOT is not /, it indicates we are installing the package for use on a different system or in a container. In either case, the tmpfiles would be processed upon boot when that system/container is started. I find this fairly obvious, but if William wants to document it that's fine. > I also prefer some things this way: > > - Indent the contents of the first `if` block for consistency's sake, > and less confusion. I disagree; indenting the entire eclass is silly and does not really improve readability. Also, this is a very common pattern found in other eclasses. > - Patterns in the `case` block doesn't have to be indented. This makes > the contents of the `case` block aligned with the contents of the > other blocks (`if`, `while`, etc.), and it makes the use of indents at > minimum when the block is used recursively. Sorry, I have no idea what you're trying to say here. Recursive blocks? This really feels like you're making a personal style suggestion here, and I personally see nothing wrong with it as-is.
Re: [gentoo-dev] new eclass: tmpfiles.eclass round 4
There are some things I noticed in the tmpfiles_process() function: - `type` currently also checks for functions, alias, and builtins, besides executable files. If that's not intended, the `-P` option should be added. - What happens if neither systemd-tmpfiles nor opentmpfiles is found? - Shouldn't the function return a nonzero if an error occurs? It would help scripts abort. - `[[ ${ROOT} == / ]] || return 0` seems to present a harmless false condition, and it doesn't show an error message. I would be helpful to have a comment added above it to give details why. I also prefer some things this way: - Indent the contents of the first `if` block for consistency's sake, and less confusion. - Patterns in the `case` block doesn't have to be indented. This makes the contents of the `case` block aligned with the contents of the other blocks (`if`, `while`, etc.), and it makes the use of indents at minimum when the block is used recursively. - The subject word in the case block does not have to be quoted. - Always keep blocks isolated from adjacent lines. -- konsolebox tmpfiles.eclass Description: Binary data
[gentoo-dev] new eclass: tmpfiles.eclass round 4
# Copyright 1999-2016 Gentoo Foundation # Distributed under the terms of the GNU General Public License v2 # $Id$ # @ECLASS: tmpfiles.eclass # @MAINTAINER: # Gentoo systemd project# William Hubbs # @AUTHOR: # Mike Gilbert # William Hubbs # @BLURB: Functions related to tmpfiles.d files # @DESCRIPTION: # This eclass provides functionality related to installing and # creating volatile and temporary files based on configuration files$and # locations defined at this URL: # # https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html # # The dotmpfiles and newtmpfiles functions are used to install # configuration files into /usr/lib/tmpfiles.d, then in pkg_postinst, the # tmpfiles_process function can be called to process the newly # installed tmpfiles.d entries. # # @EXAMPLE: # Typical usage of this eclass: # # @CODE # EAPI=6 # inherit tmpfiles # # ... # # src_install() { # ... # dotmpfiles "${FILESDIR}"/file1.conf "${FILESDIR}"/file2.conf # newtmpfiles "${FILESDIR}"/file3.conf-${PV} file3.conf # ... # } # # pkg_postinst() { # ... # tmpfiles_process file1.conf file2.conf file3.conf # ... # } # # @CODE if [[ -z ${TMPFILES_ECLASS} ]]; then TMPFILES_ECLASS=1 case "${EAPI}" in 6) ;; *) die "API is undefined for EAPI ${EAPI}" ;; esac RDEPEND="virtual/tmpfiles" # @FUNCTION: dotmpfiles # @USAGE: dotmpfiles ... # @DESCRIPTION: # Install one or more tmpfiles.d files into /usr/lib/tmpfiles.d. dotmpfiles() { debug-print-function "${FUNCNAME}" "$@" local f for f; do if [[ ${f} != *.conf ]] die "tmpfiles.d files must end with .conf" fi done ( insinto /usr/lib/tmpfiles.d doins "$@" ) } # @FUNCTION: newtmpfiles # @USAGE: newtmpfiles .conf # @DESCRIPTION: # Install a tmpfiles.d file in /usr/lib/tmpfiles.d under a new name. newtmpfiles() { debug-print-function "${FUNCNAME}" "$@" if [[ $2 != *.conf ]]; then die "tmpfiles.d files must end with .conf" fi ( insinto /usr/lib/tmpfiles.d newins "$@" ) } # @FUNCTION: tmpfiles_process # @USAGE: tmpfiles_process ... # @DESCRIPTION: # Call a tmpfiles.d implementation to create new volatile and temporary # files and directories. tmpfiles_process() { debug-print-function "${FUNCNAME}" "$@" [[ ${EBUILD_PHASE} == postinst ]] || die "${FUNCNAME}: Only valid in pkg_postinst" [[ ${#} -gt 0 ]] || die "${FUNCNAME}: Must specify at least one filename" [[ ${ROOT} == / ]] || return 0 local rc=0 if type systemd-tmpfiles &> /dev/null; then systemd-tmpfiles --create "$@" rc=$? elif type opentmpfiles &> /dev/null; then opentmpfiles --create "$@" rc=$? fi if [[ $rc -ne 0 ]]; then ewarn "The tmpfiles processor failed with exit code $rc." fi } fi signature.asc Description: Digital signature