Using macOS, you may have had experiences of handling plist files. For example,
~/Library/Preferences/.GlobalPreferences.plist file holds some configurations of macOS. When you type
defaults write -g ApplePressAndHoldEnabled -bool false on terminal, the following lines are added to
So when you dig down the preferences or resources of macOS system, you’ll meet plist files.
darfink’s vim-plist plugin handles *.plist files quite well. A plist file is in one of three formats; json, binary, xml. macOS is bundled with the
plutil command that can convert a plist file from one format to another. The plugin also uses
plutil to handle read and write of plist files.
The plugin registers autocmd for
FileReadCmd to read *.plist files,
FileWriteCmd to write *.plist files.
BufWrite events are triggered after reading the file into the buffer, but
BufWriteCmd events are triggered before reading the file, and that autocmd should handle actual read and write operation of that file. These differences make handling plist files more complex.
Overall, the plugin is quite useful and seamless. But recently, I found some *.strings plist files under
/System/Library, almost of them in binary formats. The plugin registers autocmds only for *.plist files, so there is no chance to convert them to readable formats.
At first, I’ve considered to register an autocmd for *.strings file, but I’m not sure about that
.strings extension is only used for plist file, and also there can be other extensions with plist contents (for example, *.nib files are plist, too).
Saving a new file
darfink’s vim-plist checks
b:plist_save_format before writing to plist files. The buffer-local variable is set when the plugin reads the file and detect the format. The global one is set by user, and overrides buffer-local one.
I don’t want the plugin to override the content of plist files with different format, so I haven’t set
g:plist_save_format. Then the problem raised. Open a new plist file, like
vim test.plist, and save it after editing. Then the plugin didn’t set
b:plist_save_format because it’s a new file, and I also didn’t set
g:plist_save_format, so the plugin don’t know the format to use for saving.
I think this problem can be solved by patching the plugin, but its last commit is pushed in 2014, which makes me use the faster way.
Solving the problems with .vimrc
Binary plist files
I decided to check if the file is binary plist file or not, and load with functions of vim-plist plugin. The checking process is easy, because the file starts with
bplist. At first, I think it’s okay to register an autocmd for
BufReadCmd because calling functions of the plugin should be easy. So my first try was:
function! s:DetectBinaryPlist() let l:filename = expand('<afile>') if filereadable(l:filename) let l:content = readfile(l:filename, 'b', 1) if len(content) > 0 && content =~# '^bplist' return 1 endif endif return 0 endfunction autocmd BufReadCmd * \ if s:DetectBinaryPlist() | \ call plist#Read(1) | \ call plist#ReadPost() | \ endif
Can you see the problem? This makes Vim returns an empty buffer when it reads a file that’s not a binary plist file. As I said above,
BufReadCmd should handle actual read and write operation of the file. If it’s not a binary plist file, Vim won’t read anything according to this code.
So I changed
BufRead. This event happens after reading the file into the buffer, so I have to empty the buffer.
function! s:ConvertBinaryPlist() silent! execute '%d' call plist#Read(1) call plist#ReadPost() endfunction autocmd BufRead * \ if getline(1) =~# '^bplist' | \ call s:ConvertBinaryPlist() | \ endif
getline(1) reads the first line of the buffer, and we can call it because it’s after reading the file. It’s working quite well, so at that time, I wanted to bring the writing functionality also.
function! s:ConvertBinaryPlist() silent! execute '%d' call plist#Read(1) call plist#ReadPost() autocmd! BufWriteCmd,FileWriteCmd <buffer> autocmd BufWriteCmd,FileWriteCmd <buffer> \ call plist#Write() endfunction
Note that the
autocmd! line means deleting every other
FileWriteCmd autocmds for that buffer, and the second line registers
FileWriteCmd for that buffer.
But when I saved after editing a *.strings file, I saw this error message:
<stdin>: Property List error: Unable to convert string to correct encoding / JSON error: JSON text did not start with array or object and option to allow fragments not set.
After poking around, I found that the
fileencoding is set to
latin1. The original file is binary and we just replaced the contents of the buffer, the
fileencoding was not properly set. So I just set it to UTF-8.
function! s:ConvertBinaryPlist() silent! execute '%d' call plist#Read(1) call plist#ReadPost() set fileencoding=utf-8 autocmd! BufWriteCmd,FileWriteCmd <buffer> autocmd BufWriteCmd,FileWriteCmd <buffer> \ call plist#Write() endfunction
Saving a new file
autocmd BufNewFile *.plist \ if !get(b:, 'plist_original_format') | \ let b:plist_original_format = 'xml' | \ endif
We don’t write binary file by our own hands, so a new plist file would be in xml format.
So this is the complete part of my .vimrc for binary plist files:
function! s:ConvertBinaryPlist() silent! execute '%d' call plist#Read(1) call plist#ReadPost() set fileencoding=utf-8 autocmd! BufWriteCmd,FileWriteCmd <buffer> autocmd BufWriteCmd,FileWriteCmd <buffer> \ call plist#Write() endfunction autocmd BufRead * \ if getline(1) =~# '^bplist' | \ call s:ConvertBinaryPlist() | \ endif autocmd BufNewFile *.plist \ if !get(b:, 'plist_original_format') | \ let b:plist_original_format = 'xml' | \ endif