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author | Yorick Peterse <yorickpeterse@gmail.com> | 2016-05-26 13:13:57 +0200 |
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committer | Yorick Peterse <yorickpeterse@gmail.com> | 2016-05-26 13:58:01 +0200 |
commit | 94d5416db6415b06706204fb4a4df0100bcab7be (patch) | |
tree | 566e4525629241e3182296afd12e4e92ebaa863f /lib/gitlab/lazy.rb | |
parent | 309ca405fa30e1eeaeaeddc0c8918e65c98ebbf7 (diff) | |
download | gitlab-ce-94d5416db6415b06706204fb4a4df0100bcab7be.tar.gz |
Added Gitlab::Lazy
This class can be used to lazy-evaluate blocks of code the first time
they're called. This can be useful when a method performs a certain
heavy operation (e.g. a SQL query) that you only want to perform
whenever the result is used for the first time.
Diffstat (limited to 'lib/gitlab/lazy.rb')
-rw-r--r-- | lib/gitlab/lazy.rb | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/gitlab/lazy.rb b/lib/gitlab/lazy.rb new file mode 100644 index 00000000000..2a659ae4c74 --- /dev/null +++ b/lib/gitlab/lazy.rb @@ -0,0 +1,34 @@ +module Gitlab + # A class that can be wrapped around an expensive method call so it's only + # executed when actually needed. + # + # Usage: + # + # object = Gitlab::Lazy.new { some_expensive_work_here } + # + # object['foo'] + # object.bar + class Lazy < BasicObject + def initialize(&block) + @block = block + end + + def method_missing(name, *args, &block) + __evaluate__ + + @result.__send__(name, *args, &block) + end + + def respond_to_missing?(name, include_private = false) + __evaluate__ + + @result.respond_to?(name, include_private) || super + end + + private + + def __evaluate__ + @result = @block.call unless defined?(@result) + end + end +end |