class Rake::Task - rake-10.3.2 Documentation

# class Rake::Task

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.

### Attributes

actions[R]

List of actions attached to a task.

application[RW]

Application owning this task.

locations[R]

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).

prerequisites[R]

List of prerequisites for a task.

scope[R]

Array of nested namespaces names used for task lookup by this task.

sources[W]

List of sources for task.

### Public Class Methods

new(task_name, app) click to toggle source

Create a task named `task_name` with no actions or prerequisites. Use `enhance` to add actions and prerequisites.

    # File lib/rake/task.rb, line 86
    def initialize(task_name, app)
      @name            = task_name.to_s
      @prerequisites   = []
      @actions         = []
      @already_invoked = false
      @comments        = []
      @lock            = Monitor.new
      @application     = app
      @scope           = app.current_scope
      @arg_names       = nil
      @locations       = []
    end

### Public Instance Methods

[](task_name) click to toggle source

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.

    # File lib/rake/task.rb, line 352
    def [](task_name)
      Rake.application[task_name]
    end

add_description(description) click to toggle source

Add a description to the task. The description can consist of an option argument list (enclosed brackets) and an optional comment.

    # File lib/rake/task.rb, line 258
    def add_description(description)
      return unless description
      comment = description.strip
      add_comment(comment) if comment && ! comment.empty?
    end

all_prerequisite_tasks() click to toggle source

List of all unique prerequisite tasks including prerequisite tasks' prerequisites. Includes self when cyclic dependencies are found.

    # File lib/rake/task.rb, line 64
    def all_prerequisite_tasks
      seen = {}
      collect_prerequisites(seen)
      seen.values
    end

arg_names() click to toggle source

Name of arguments for this task.

    # File lib/rake/task.rb, line 126
    def arg_names
      @arg_names || []
    end

clear() click to toggle source

Clear the existing prerequisites and actions of a rake task.

    # File lib/rake/task.rb, line 137
    def clear
      clear_prerequisites
      clear_actions
      clear_comments
      self
    end

clear_actions() click to toggle source

Clear the existing actions on a rake task.

    # File lib/rake/task.rb, line 151
    def clear_actions
      actions.clear
      self
    end

clear_comments() click to toggle source

Clear the existing comments on a rake task.

    # File lib/rake/task.rb, line 157
    def clear_comments
      @comments = []
      self
    end

clear_prerequisites() click to toggle source

Clear the existing prerequisites of a rake task.

    # File lib/rake/task.rb, line 145
    def clear_prerequisites
      prerequisites.clear
      self
    end

comment() click to toggle source

First line (or sentence) of all comments. Multiple comments are separated by a “/”.

    # File lib/rake/task.rb, line 282
    def comment
      transform_comments(" / ") { |c| first_sentence(c) }
    end

create_rule(*args, &block) click to toggle source

Define a rule for synthesizing tasks.

    # File lib/rake/task.rb, line 369
    def create_rule(*args, &block)
      Rake.application.create_rule(*args, &block)
    end

define_task(*args, &block) click to toggle source

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.

    # File lib/rake/task.rb, line 364
    def define_task(*args, &block)
      Rake.application.define_task(self, *args, &block)
    end

enhance(deps=nil, &block) click to toggle source

Enhance a task with prerequisites or actions. Returns self.

    # File lib/rake/task.rb, line 100
    def enhance(deps=nil, &block)
      @prerequisites |= deps if deps
      @actions << block if block_given?
      self
    end

execute(args=nil) click to toggle source

Execute the actions associated with this task.

    # File lib/rake/task.rb, line 227
    def execute(args=nil)
      args ||= EMPTY_TASK_ARGS
      if application.options.dryrun
        application.trace "** Execute (dry run) #{name}"
        return
      end
      application.trace "** Execute #{name}" if application.options.trace
      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

full_comment() click to toggle source

Full collection of comments. Multiple comments are separated by newlines.

    # File lib/rake/task.rb, line 276
    def full_comment
      transform_comments("\n")
    end

investigation() click to toggle source

Return a string describing the internal state of a task. Useful for debugging.

    # File lib/rake/task.rb, line 314
    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.map { |pre| pre.timestamp }.max
      result <<  "latest-prerequisite time: #{latest_prereq}\n"
      result << "................................\n\n"
      return result
    end

invoke(*args) click to toggle source

Invoke the task if it is needed. Prerequisites are invoked first.

    # File lib/rake/task.rb, line 163
    def invoke(*args)
      task_args = TaskArguments.new(arg_names, args)
      invoke_with_call_chain(task_args, InvocationChain::EMPTY)
    end

name() click to toggle source

Name of the task, including any namespace qualifiers.

    # File lib/rake/task.rb, line 107
    def name
      @name.to_s
    end

needed?() click to toggle source

Is this task needed?

    # File lib/rake/task.rb, line 246
    def needed?
      true
    end

prerequisite_tasks() click to toggle source

List of prerequisite tasks

    # File lib/rake/task.rb, line 52
    def prerequisite_tasks
      prerequisites.map { |pre| lookup_prerequisite(pre) }
    end

reenable() click to toggle source

Reenable the task, allowing its tasks to be executed if the task is invoked again.

    # File lib/rake/task.rb, line 132
    def reenable
      @already_invoked = false
    end

scope_name(scope, task_name) click to toggle source

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.

    # File lib/rake/task.rb, line 376
          def scope_name(scope, task_name)
    #        (scope + [task_name]).join(':')
            scope.path_with_task_name(task_name)
          end

set_arg_names(args) click to toggle source

Set the names of the arguments for this task. `args` should be an array of symbols, one for each argument name.

    # File lib/rake/task.rb, line 308
    def set_arg_names(args)
      @arg_names = args.map { |a| a.to_sym }
    end

source() click to toggle source

First source from a rule (nil if no sources)

    # File lib/rake/task.rb, line 80
    def source
      sources.first
    end

sources() click to toggle source

    # File lib/rake/task.rb, line 43
    def sources
      if defined?(@sources)
        @sources
      else
        prerequisites
      end
    end

task_defined?(task_name) click to toggle source

TRUE if the task name is already defined.

    # File lib/rake/task.rb, line 357
    def task_defined?(task_name)
      Rake.application.lookup(task_name) != nil
    end

tasks() click to toggle source

List of all defined tasks.

    # File lib/rake/task.rb, line 344
    def tasks
      Rake.application.tasks
    end

timestamp() click to toggle source

Timestamp for this task. Basic tasks return the current time for their time stamp. Other tasks can be more sophisticated.

    # File lib/rake/task.rb, line 252
    def timestamp
      Time.now
    end

to_s() click to toggle source

Return task name

    # File lib/rake/task.rb, line 33
    def to_s
      name
    end

### Private Instance Methods

first_sentence(string) click to toggle source

Get the first sentence in a string. The sentence is terminated by the first period or the end of the line. Decimal points do not count as periods.

    # File lib/rake/task.rb, line 301
    def first_sentence(string)
      string.split(/\.[ \t]|\.$|\n/).first
    end

format_trace_flags() click to toggle source

Format the trace flags for display.

    # File lib/rake/task.rb, line 218
    def format_trace_flags
      flags = []
      flags << "first_time" unless @already_invoked
      flags << "not_needed" unless needed?
      flags.empty? ? "" : "(" + flags.join(", ") + ")"
    end

transform_comments(separator, &block) click to toggle source

Transform the list of comments as specified by the block and join with the separator.

    # File lib/rake/task.rb, line 288
    def transform_comments(separator, &block)
      if @comments.empty?
        nil
      else
        block ||= lambda { |c| c }
        @comments.map(&block).join(separator)
      end
    end