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Diffstat (limited to 'lib/rake/task.rb')
| -rw-r--r-- | lib/rake/task.rb | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/lib/rake/task.rb b/lib/rake/task.rb new file mode 100644 index 0000000000..f977d18711 --- /dev/null +++ b/lib/rake/task.rb @@ -0,0 +1,327 @@ +require 'rake/invocation_exception_mixin' + +module Rake + + # ######################################################################### + # A Task is the basic unit of work in a Rakefile. Tasks have associated + # actions (possibly more than one) and a list of prerequisites. When + # invoked, a task will first ensure that all of its prerequisites have an + # opportunity to run and then it will execute its own actions. + # + # Tasks are not usually created directly using the new method, but rather + # use the +file+ and +task+ convenience methods. + # + class Task + # List of prerequisites for a task. + attr_reader :prerequisites + + # List of actions attached to a task. + attr_reader :actions + + # Application owning this task. + attr_accessor :application + + # Comment for this task. Restricted to a single line of no more than 50 + # characters. + attr_reader :comment + + # Full text of the (possibly multi-line) comment. + attr_reader :full_comment + + # Array of nested namespaces names used for task lookup by this task. + attr_reader :scope + + # File/Line locations of each of the task definitions for this + # task (only valid if the task was defined with the detect + # location option set). + attr_reader :locations + + # Return task name + def to_s + name + end + + def inspect + "<#{self.class} #{name} => [#{prerequisites.join(', ')}]>" + end + + # List of sources for task. + attr_writer :sources + def sources + @sources ||= [] + end + + # List of prerequisite tasks + def prerequisite_tasks + prerequisites.collect { |pre| lookup_prerequisite(pre) } + end + + def lookup_prerequisite(prerequisite_name) + application[prerequisite_name, @scope] + end + private :lookup_prerequisite + + # First source from a rule (nil if no sources) + def source + @sources.first if defined?(@sources) + end + + # Create a task named +task_name+ with no actions or prerequisites. Use + # +enhance+ to add actions and prerequisites. + def initialize(task_name, app) + @name = task_name.to_s + @prerequisites = [] + @actions = [] + @already_invoked = false + @full_comment = nil + @comment = nil + @lock = Monitor.new + @application = app + @scope = app.current_scope + @arg_names = nil + @locations = [] + end + + # Enhance a task with prerequisites or actions. Returns self. + def enhance(deps=nil, &block) + @prerequisites |= deps if deps + @actions << block if block_given? + self + end + + # Name of the task, including any namespace qualifiers. + def name + @name.to_s + end + + # Name of task with argument list description. + def name_with_args # :nodoc: + if arg_description + "#{name}#{arg_description}" + else + name + end + end + + # Argument description (nil if none). + def arg_description # :nodoc: + @arg_names ? "[#{(arg_names || []).join(',')}]" : nil + end + + # Name of arguments for this task. + def arg_names + @arg_names || [] + end + + # Reenable the task, allowing its tasks to be executed if the task + # is invoked again. + def reenable + @already_invoked = false + end + + # Clear the existing prerequisites and actions of a rake task. + def clear + clear_prerequisites + clear_actions + self + end + + # Clear the existing prerequisites of a rake task. + def clear_prerequisites + prerequisites.clear + self + end + + # Clear the existing actions on a rake task. + def clear_actions + actions.clear + self + end + + # Invoke the task if it is needed. Prerequisites are invoked first. + def invoke(*args) + task_args = TaskArguments.new(arg_names, args) + invoke_with_call_chain(task_args, InvocationChain::EMPTY) + end + + # Same as invoke, but explicitly pass a call chain to detect + # circular dependencies. + def invoke_with_call_chain(task_args, invocation_chain) # :nodoc: + new_chain = InvocationChain.append(self, invocation_chain) + @lock.synchronize do + if application.options.trace + $stderr.puts "** Invoke #{name} #{format_trace_flags}" + end + return if @already_invoked + @already_invoked = true + invoke_prerequisites(task_args, new_chain) + execute(task_args) if needed? + end + rescue Exception => ex + add_chain_to(ex, new_chain) + raise ex + end + protected :invoke_with_call_chain + + def add_chain_to(exception, new_chain) + exception.extend(InvocationExceptionMixin) unless exception.respond_to?(:chain) + exception.chain = new_chain if exception.chain.nil? + end + private :add_chain_to + + # Invoke all the prerequisites of a task. + def invoke_prerequisites(task_args, invocation_chain) # :nodoc: + prerequisite_tasks.each { |prereq| + prereq_args = task_args.new_scope(prereq.arg_names) + prereq.invoke_with_call_chain(prereq_args, invocation_chain) + } + end + + # Format the trace flags for display. + def format_trace_flags + flags = [] + flags << "first_time" unless @already_invoked + flags << "not_needed" unless needed? + flags.empty? ? "" : "(" + flags.join(", ") + ")" + end + private :format_trace_flags + + # Execute the actions associated with this task. + def execute(args=nil) + args ||= EMPTY_TASK_ARGS + if application.options.dryrun + $stderr.puts "** Execute (dry run) #{name}" + return + end + if application.options.trace + $stderr.puts "** Execute #{name}" + end + application.enhance_with_matching_rule(name) if @actions.empty? + @actions.each do |act| + case act.arity + when 1 + act.call(self) + else + act.call(self, args) + end + end + end + + # Is this task needed? + def needed? + true + end + + # Timestamp for this task. Basic tasks return the current time for their + # time stamp. Other tasks can be more sophisticated. + def timestamp + prerequisite_tasks.collect { |pre| pre.timestamp }.max || Time.now + end + + # Add a description to the task. The description can consist of an option + # argument list (enclosed brackets) and an optional comment. + def add_description(description) + return if ! description + comment = description.strip + add_comment(comment) if comment && ! comment.empty? + end + + # Writing to the comment attribute is the same as adding a description. + def comment=(description) + add_description(description) + end + + # Add a comment to the task. If a comment already exists, separate + # the new comment with " / ". + def add_comment(comment) + if @full_comment + @full_comment << " / " + else + @full_comment = '' + end + @full_comment << comment + if @full_comment =~ /\A([^.]+?\.)( |$)/ + @comment = $1 + else + @comment = @full_comment + end + end + private :add_comment + + # Set the names of the arguments for this task. +args+ should be + # an array of symbols, one for each argument name. + def set_arg_names(args) + @arg_names = args.map { |a| a.to_sym } + end + + # Return a string describing the internal state of a task. Useful for + # debugging. + def investigation + result = "------------------------------\n" + result << "Investigating #{name}\n" + result << "class: #{self.class}\n" + result << "task needed: #{needed?}\n" + result << "timestamp: #{timestamp}\n" + result << "pre-requisites: \n" + prereqs = prerequisite_tasks + prereqs.sort! {|a,b| a.timestamp <=> b.timestamp} + prereqs.each do |p| + result << "--#{p.name} (#{p.timestamp})\n" + end + latest_prereq = prerequisite_tasks.collect { |pre| pre.timestamp }.max + result << "latest-prerequisite time: #{latest_prereq}\n" + result << "................................\n\n" + return result + end + + # ---------------------------------------------------------------- + # Rake Module Methods + # + class << self + + # Clear the task list. This cause rake to immediately forget all the + # tasks that have been assigned. (Normally used in the unit tests.) + def clear + Rake.application.clear + end + + # List of all defined tasks. + def tasks + Rake.application.tasks + end + + # Return a task with the given name. If the task is not currently + # known, try to synthesize one from the defined rules. If no rules are + # found, but an existing file matches the task name, assume it is a file + # task with no dependencies or actions. + def [](task_name) + Rake.application[task_name] + end + + # TRUE if the task name is already defined. + def task_defined?(task_name) + Rake.application.lookup(task_name) != nil + end + + # Define a task given +args+ and an option block. If a rule with the + # given name already exists, the prerequisites and actions are added to + # the existing task. Returns the defined task. + def define_task(*args, &block) + Rake.application.define_task(self, *args, &block) + end + + # Define a rule for synthesizing tasks. + def create_rule(*args, &block) + Rake.application.create_rule(*args, &block) + end + + # Apply the scope to the task name according to the rules for + # this kind of task. Generic tasks will accept the scope as + # part of the name. + def scope_name(scope, task_name) + (scope + [task_name]).join(':') + end + + end # class << Rake::Task + end # class Rake::Task +end |