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// file : libbuild2/rule.hxx -*- C++ -*-
// license : MIT; see accompanying LICENSE file
#ifndef LIBBUILD2_RULE_HXX
#define LIBBUILD2_RULE_HXX
#include <libbuild2/types.hxx>
#include <libbuild2/forward.hxx>
#include <libbuild2/utility.hxx>
#include <libbuild2/action.hxx>
#include <libbuild2/target.hxx>
#include <libbuild2/recipe.hxx>
#include <libbuild2/export.hxx>
namespace build2
{
// Rule interface (see also simple_rule below for a simplified version).
//
// Once a rule is registered (for a scope), it is treated as immutable. If
// you need to modify some state (e.g., counters or some such), then make
// sure things are MT-safe.
//
// Note: match() is only called once but may not be followed by apply().
//
class LIBBUILD2_SYMEXPORT rule
{
public:
// The match_extra argument is used to pass additional information that is
// only needed by some rule implementations. It is also a way for us to
// later pass more information without breaking source compatibility.
//
struct match_extra
{
};
virtual bool
match (action, target&, const string& hint, match_extra&) const = 0;
virtual recipe
apply (action, target&, match_extra&) const = 0;
rule () = default;
virtual
~rule ();
rule (const rule&) = delete;
rule& operator= (const rule&) = delete;
};
// Simplified interface for rules that don't care about the extras.
//
class LIBBUILD2_SYMEXPORT simple_rule: public rule
{
public:
virtual bool
match (action, target&, const string& hint) const = 0;
virtual recipe
apply (action, target&) const = 0;
virtual bool
match (action, target&, const string&, match_extra&) const override;
virtual recipe
apply (action, target&, match_extra&) const override;
};
// Fallback rule that only matches if the file exists. It will also match
// an mtime_target provided it has a set timestamp.
//
class LIBBUILD2_SYMEXPORT file_rule: public simple_rule
{
public:
virtual bool
match (action, target&, const string&) const override;
virtual recipe
apply (action, target&) const override;
file_rule () {}
static const file_rule instance;
};
class LIBBUILD2_SYMEXPORT alias_rule: public simple_rule
{
public:
virtual bool
match (action, target&, const string&) const override;
virtual recipe
apply (action, target&) const override;
alias_rule () {}
static const alias_rule instance;
};
// Note that this rule ignores the dry_run flag; see mkdir() in filesystem
// for the rationale.
//
class LIBBUILD2_SYMEXPORT fsdir_rule: public simple_rule
{
public:
virtual bool
match (action, target&, const string&) const override;
virtual recipe
apply (action, target&) const override;
static target_state
perform_update (action, const target&);
static target_state
perform_clean (action, const target&);
// Sometimes, as an optimization, we want to emulate execute_direct()
// of fsdir{} without the overhead of switching to the execute phase.
//
static void
perform_update_direct (action, const target&);
fsdir_rule () {}
static const fsdir_rule instance;
};
// Fallback rule that always matches and does nothing.
//
class LIBBUILD2_SYMEXPORT noop_rule: public simple_rule
{
public:
virtual bool
match (action, target&, const string&) const override;
virtual recipe
apply (action, target&) const override;
noop_rule () {}
static const noop_rule instance;
};
// Ad hoc rule.
//
// Note: not exported.
//
class adhoc_rule: public simple_rule
{
public:
location_value loc; // Buildfile location of the recipe.
size_t braces; // Number of braces in multi-brace tokens.
adhoc_rule (const char* name, const location& l, size_t b)
: loc (l),
braces (b),
rule_match (name, static_cast<const rule&> (*this)) {}
// Set the rule text, handle any recipe-specific attributes, and return
// true if the recipe builds anything in the build/recipes/ directory and
// therefore requires cleanup.
//
virtual bool
recipe_text (context&, const target&, string&&, attributes&) = 0;
public:
// Some of the operations come in compensating pairs, such as update and
// clean, install and uninstall. An ad hoc rule implementation may choose
// to provide a fallback implementation of a compensating operation if it
// is providing the other half (passed in the fallback argument).
//
// The default implementation calls rule::match() if fallback is absent
// and returns false if fallback is present. So an implementation that
// doesn't care about this semantics can implement the straight rule
// interface.
//
virtual bool
match (action, target&, const string&, optional<action> fallback) const;
virtual bool
match (action, target&, const string&) const override;
// Dump support.
//
virtual void
dump_attributes (ostream&) const;
virtual void
dump_text (ostream&, string& indentation) const = 0;
// Implementation details.
//
public:
// The name in rule_match is used as a hint and as a name in diagnostics.
// The former does not apply to us (but will apply to ad hoc rules) while
// latter does. As a result, we use special-looking "<ad hoc X recipe>"
// names.
//
build2::rule_match rule_match;
static const dir_path recipes_build_dir;
// Scope operation callback that cleans up ad hoc recipe builds.
//
static target_state
clean_recipes_build (action, const scope&, const dir&);
};
}
#endif // LIBBUILD2_RULE_HXX
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