+ /**
+ Finds dependencies for the target. When all dependencies have been found,
+ the function should set deps_ready to true.
+ */
+ virtual void find_depends() { deps_ready = true; }
+
+ /**
+ Prepares the target by recursively preparing dependencies, then checking
+ whether rebuilding is needed. A flag is used to prevent unnecessary
+ executions.
+ */
+ virtual void prepare();
+
+ /**
+ Starts building the target. Returns the Action used for building.
+ */
+ Action *build();
+protected: