github-url: Move functions into `autoload`

Improve performance by eliminating the functions from the `plugin` file.

Also introduces a new `github_url#GitHubURL()` function that serves as
an entry point into the plugin.

Add a `g:loaded_github_url` check to prevent plugin re-sourcing and be a
good Vim citizen.

1 files changed, 35 insertions, 0 deletions

diff --git a/bundle/github-url/autoload/github_url.vim b/bundle/github-url/autoload/github_url.vim
new file mode 100644
index 0000000..11110a8
--- /dev/null
+++ b/bundle/github-url/autoload/github_url.vim
@@ -0,0 +1,35 @@
+" Constructs a GitHub URL for the current Git repo by making substitutions to
+" the SSH location to turn it into an HTTP URL.
+function! s:BaseRepoURL()
+	let remote = system('git remote get-url origin')
+	let base_url = substitute(remote, ':', '/', '')
+	let base_url = substitute(base_url, '^git@', 'https://', '')
+	let base_url = substitute(base_url, '.git\n$', '', '')
+
+	return base_url
+endfunction
+
+" Constructs a GitHub URL to the current file using the current HEAD's SHA. If
+" lines are passed in, these are included in the URL. The `include_lines`
+" argument comes from a `:command`'s `<count>`, and tells the function whether
+" a range was given.
+function! s:FileURL(include_lines, start_line, end_line)
+	let current_sha = system('git show --format="format:%H"')
+	let current_sha = substitute(current_sha, '\n$', '', '')
+	let current_filename = expand('%')
+	let lines = ''
+
+	if a:include_lines
+		let lines = '#L' . a:start_line
+
+		if a:start_line != a:end_line
+			let lines = lines . '-L' . a:end_line
+		endif
+	endif
+
+	return s:BaseRepoURL() . '/blob/' . current_sha . '/' . current_filename . lines
+endfunction
+
+function! github_url#GitHubURL(include_lines, start_line, end_line)
+	return s:FileURL(a:include_lines, a:start_line, a:end_line)
+endfunction