dependencies.rb in activesupport-1.3.0

- old
+ new

@@ -1,209 +1,131 @@
-require File.dirname(__FILE__) + '/module_attribute_accessors'
+require 'set'
+require File.dirname(__FILE__) + '/core_ext/module/attribute_accessors'
 require File.dirname(__FILE__) + '/core_ext/load_error'
+require File.dirname(__FILE__) + '/core_ext/kernel'
 
 module Dependencies #:nodoc:
   extend self
 
-  @@loaded = [ ]
+  # Should we turn on Ruby warnings on the first load of dependent files?
+  mattr_accessor :warnings_on_first_load
+  self.warnings_on_first_load = false
+
+  # All files ever loaded.
+  mattr_accessor :history
+  self.history = Set.new
+
+  # All files currently loaded.
   mattr_accessor :loaded
+  self.loaded = Set.new
 
-  @@mechanism = :load
+  # Should we load files or require them?
   mattr_accessor :mechanism
-  
+  self.mechanism = :load
+
   def load?
     mechanism == :load
   end
-  
-  def depend_on(file_name, swallow_load_errors = false)
-    unless loaded.include?(file_name)
-      loaded << file_name
 
-      begin
-        require_or_load(file_name)
-      rescue LoadError
-        raise unless swallow_load_errors
-      end
-    end
+  def depend_on(file_name, swallow_load_errors = false)
+    require_or_load(file_name)
+  rescue LoadError
+    raise unless swallow_load_errors
   end
 
   def associate_with(file_name)
     depend_on(file_name, true)
   end
-  
+
   def clear
-    self.loaded = [ ]
+    loaded.clear
   end
-  
+
   def require_or_load(file_name)
-    file_name = "#{file_name}.rb" unless ! load? || file_name[-3..-1] == '.rb'
-    load? ? load(file_name) : require(file_name)
-  end
-  
-  def remove_subclasses_for(*classes)
-    Object.remove_subclasses_of(*classes)
-  end
-  
-  # LoadingModules implement namespace-safe dynamic loading.
-  # They support automatic loading via const_missing, allowing contained items to be automatically
-  # loaded when required. No extra syntax is required, as expressions such as Controller::Admin::UserController
-  # load the relavent files automatically.
-  #
-  # Ruby-style modules are supported, as a folder named 'submodule' will load 'submodule.rb' when available.
-  class LoadingModule < Module #:nodoc:
-    attr_reader :path
-    attr_reader :root
-    
-    class << self
-      def root(*load_paths)
-        RootLoadingModule.new(*load_paths)
-      end
-    end
-    
-    def initialize(root, path=[])
-      @path = path.clone.freeze
-      @root = root
-    end
-    
-    def root?()      self.root == self    end
-    def load_paths() self.root.load_paths end
-    
-    # Load missing constants if possible.
-    def const_missing(name)
-      const_load!(name) ? const_get(name) : super(name)
-    end
-  
-    # Load the controller class or a parent module.
-    def const_load!(name, file_name = nil)
-      file_name ||= 'application' if root? && name.to_s == 'ApplicationController'
-      path = self.path + [file_name || name]
+    file_name = $1 if file_name =~ /^(.*)\.rb$/
+    return if loaded.include?(file_name)
 
-      load_paths.each do |load_path|
-        fs_path = load_path.filesystem_path(path)
-        next unless fs_path
+    # Record that we've seen this file *before* loading it to avoid an
+    # infinite loop with mutual dependencies.
+    loaded << file_name
 
-        case 
-        when File.directory?(fs_path)
-          new_module = LoadingModule.new(self.root, self.path + [name])
-          self.const_set name, new_module
-          if self.root?
-            if Object.const_defined?(name)
-              msg = "Cannot load module #{name}: Object::#{name} is set to #{Object.const_get(name).inspect}"
-              raise NameError, msg
-            end
-            Object.const_set(name, new_module)
-          end
-          break
-        when File.file?(fs_path)
-          loaded_file = self.root.load_file!(fs_path)
-          
-          # Import the loaded constant from Object provided we are the root node.
-          self.const_set(name, Object.const_get(name)) if self.root? && Object.const_defined?(name)
-          
-          # Throw an error if we load the file but we don't find the Object we expect
-          if loaded_file and not self.const_defined?(name)
-            msg = "Already loaded file '#{fs_path}' but '#{name.to_s}' was not set, perhaps you need to rename '#{fs_path}'?"
-            raise LoadError, msg
-          end
-          break
+    if load?
+      begin
+        # Enable warnings iff this file has not been loaded before and
+        # warnings_on_first_load is set.
+        if !warnings_on_first_load or history.include?(file_name)
+          load "#{file_name}.rb"
+        else
+          enable_warnings { load "#{file_name}.rb" }
         end
+      rescue
+        loaded.delete file_name
+        raise
       end
-      
-      self.const_defined?(name)
+    else
+      require file_name
     end
-    
-    # Is this name present or loadable?
-    # This method is used by Routes to find valid controllers.
-    def const_available?(name)
-      self.const_defined?(name) || load_paths.any? {|lp| lp.filesystem_path(path + [name])}
-    end
-  end
-  
-  class RootLoadingModule < LoadingModule #:nodoc:
-    attr_reader :load_paths
 
-    def initialize(*paths)
-      @load_paths = paths.flatten.collect {|p| p.kind_of?(ConstantLoadPath) ? p : ConstantLoadPath.new(p)}
-    end
-
-    def root() self end
-
-    def path() [] end
-    
-    # Load the source file at the given file path
-    def load_file!(file_path)
-      require_dependency(file_path)
-    end
-
-    # Erase all items in this module
-    def clear!
-      constants.each do |name|
-        Object.send(:remove_const, name) if Object.const_defined?(name) && Object.const_get(name).object_id == self.const_get(name).object_id
-        self.send(:remove_const, name)
-      end
-    end
+    # Record history *after* loading so first load gets warnings.
+    history << file_name
   end
-  
-  # This object defines a path from which Constants can be loaded.
-  class ConstantLoadPath #:nodoc:
-    # Create a new load path with the filesystem path
-    def initialize(root) @root = root end
-    
-    # Return nil if the path does not exist, or the path to a directory
-    # if the path leads to a module, or the path to a file if it leads to an object.
-    def filesystem_path(path, allow_module=true)
-      fs_path = [@root]
-      fs_path += path[0..-2].map {|name| const_name_to_module_name name}
-
-      if allow_module
-        result = File.join(fs_path, const_name_to_module_name(path.last))
-        return result if File.directory? result # Return the module path if one exists
-      end
-
-      result = File.join(fs_path, const_name_to_file_name(path.last))
-
-      File.file?(result) ? result : nil
-    end
-    
-    def const_name_to_file_name(name)
-      name.to_s.underscore + '.rb'
-    end
-
-    def const_name_to_module_name(name)
-      name.to_s.underscore
-    end
-  end
 end
 
 Object.send(:define_method, :require_or_load)     { |file_name| Dependencies.require_or_load(file_name) } unless Object.respond_to?(:require_or_load)
 Object.send(:define_method, :require_dependency)  { |file_name| Dependencies.depend_on(file_name) }       unless Object.respond_to?(:require_dependency)
 Object.send(:define_method, :require_association) { |file_name| Dependencies.associate_with(file_name) }  unless Object.respond_to?(:require_association)
 
 class Module #:nodoc:
   # Rename the original handler so we can chain it to the new one
   alias :rails_original_const_missing :const_missing
-
+  
   # Use const_missing to autoload associations so we don't have to
   # require_association when using single-table inheritance.
   def const_missing(class_id)
-    if Object.const_defined?(:Controllers) and Object::Controllers.const_available?(class_id)
-      return Object::Controllers.const_get(class_id)
-    end
-    
     file_name = class_id.to_s.demodulize.underscore
+    file_path = as_load_path.empty? ? file_name : "#{as_load_path}/#{file_name}"
     begin
-      require_dependency(file_name)
-      raise NameError.new("uninitialized constant #{class_id}") unless Object.const_defined?(class_id)
-      return Object.const_get(class_id)
+      require_dependency(file_path)
+      brief_name = self == Object ? '' : "#{name}::"
+      raise NameError.new("uninitialized constant #{brief_name}#{class_id}") unless const_defined?(class_id)
+      return const_get(class_id)
     rescue MissingSourceFile => e
-      # Convert the exception to a NameError only if the file we are looking for is the missing one.
-      raise unless e.is_missing? file_name
+      # Re-raise the error if it does not concern the file we were trying to load.
+      raise unless e.is_missing? file_path
+      
+      # Look for a directory in the load path that we ought to load.
+      if $LOAD_PATH.any? { |base| File.directory? "#{base}/#{file_path}" }
+        mod = Module.new
+        const_set class_id, mod # Create the new module
+        return mod
+      end
+      
+      # Attempt to access the name from the parent, unless we don't have a valid
+      # parent, or the constant is already defined in the parent. If the latter
+      # is the case, then we are being queried via self::class_id, and we should
+      # avoid returning the constant from the parent if possible.
+      if parent && parent != self && ! parents.any? { |p| p.const_defined?(class_id) }
+        suppress(NameError) do
+          return parent.send(:const_missing, class_id)
+        end
+      end
+      
       raise NameError.new("uninitialized constant #{class_id}").copy_blame!(e)
     end
   end
 end
 
+class Class
+  def const_missing(class_id)
+    if [Object, Kernel].include?(self) || parent == self
+      super
+    else
+      parent.send :const_missing, class_id
+    end
+  end
+end
+
 class Object #:nodoc:
   def load(file, *extras)
     super(file, *extras)
   rescue Object => exception
     exception.blame_file! file
@@ -235,6 +157,6 @@
 
   def copy_blame!(exc)
     @blamed_files = exc.blamed_files.clone
     self
   end
-end
+end
\ No newline at end of file