git.cworth.org Git - sup/blob - lib/sup/hook.rb

   1 module Redwood
   2
   3 class HookManager
   4   ## there's probably a better way to do this, but to evaluate a hook
   5   ## with a bunch of pre-set "local variables" i define a function
   6   ## per variable and then instance_evaluate the code.
   7   ##
   8   ## how does rails do it, when you pass :locals into a partial?
   9   ##
  10   ## i don't bother providing setters, since i'm pretty sure the
  11   ## charade will fall apart pretty quickly with respect to scoping.
  12   ## this is basically fail-fast.
  13   class HookContext
  14     def initialize name
  15       @__say_id = nil
  16       @__name = name
  17       @__locals = {}
  18     end
  19
  20     attr_writer :__locals
  21
  22     def method_missing m, *a
  23       case @__locals[m]
  24       when Proc
  25         @__locals[m].call(*a)
  26       when nil
  27         super
  28       else
  29         @__locals[m]
  30       end
  31     end
  32
  33     def say s
  34       if BufferManager.instantiated?
  35         @__say_id = BufferManager.say s, @__say_id
  36         BufferManager.draw_screen
  37       else
  38         log s
  39       end
  40     end
  41
  42     def log s
  43       Redwood::log "hook[#@__name]: #{s}"
  44     end
  45
  46     def ask_yes_or_no q
  47       if BufferManager.instantiated?
  48         BufferManager.ask_yes_or_no q
  49       else
  50         print q
  51         gets.chomp.downcase == 'y'
  52       end
  53     end
  54
  55     def __binding
  56       binding
  57     end
  58
  59     def __cleanup
  60       BufferManager.clear @__say_id if @__say_id
  61     end
  62   end
  63
  64   include Singleton
  65
  66   def initialize dir
  67     @dir = dir
  68     @hooks = {}
  69     @descs = {}
  70     @contexts = {}
  71
  72     Dir.mkdir dir unless File.exists? dir
  73
  74     self.class.i_am_the_instance self
  75   end
  76
  77   def run name, locals={}
  78     hook = hook_for(name) or return
  79     context = @contexts[hook] ||= HookContext.new(name)
  80     context.__locals = locals
  81
  82     result = nil
  83     begin
  84       result = context.instance_eval @hooks[name], fn_for(name)
  85     rescue Exception => e
  86       log "error running hook: #{e.message}"
  87       log e.backtrace.join("\n")
  88       BufferManager.flash "Error running hook: #{e.message}"
  89     end
  90     context.__cleanup
  91     result
  92   end
  93
  94   def register name, desc
  95     @descs[name] = desc
  96   end
  97
  98   def print_hooks f=$stdout
  99 puts <<EOS
 100 Have #{@descs.size} registered hooks:
 101
 102 EOS
 103
 104     @descs.sort.each do |name, desc|
 105       f.puts <<EOS
 106 #{name}
 107 #{"-" * name.length}
 108 File: #{fn_for name}
 109 #{desc}
 110 EOS
 111     end
 112   end
 113
 114 private
 115
 116   def hook_for name
 117     unless @hooks.member? name
 118       @hooks[name] =
 119         begin
 120           returning IO.readlines(fn_for(name)).join do
 121             log "read '#{name}' from #{fn_for(name)}"
 122           end
 123         rescue SystemCallError => e
 124           #log "disabled hook for '#{name}': #{e.message}"
 125           nil
 126         end
 127     end
 128
 129     @hooks[name]
 130   end
 131
 132   def fn_for name
 133     File.join @dir, "#{name}.rb"
 134   end
 135
 136   def log m
 137     Redwood::log("hook: " + m)
 138   end
 139 end
 140
 141 end