// file : libbuild2/algorithm.hxx -*- C++ -*- // copyright : Copyright (c) 2014-2019 Code Synthesis Ltd // license : MIT; see accompanying LICENSE file #ifndef LIBBUILD2_ALGORITHM_HXX #define LIBBUILD2_ALGORITHM_HXX #include #include #include #include #include namespace build2 { class scope; class prerequisite; class prerequisite_key; // The default prerequisite search implementation. It first calls the // prerequisite-type-specific search function. If that doesn't yeld // anything, it creates a new target. // LIBBUILD2_SYMEXPORT const target& search (const target&, const prerequisite&); // As above but only search for an already existing target. // LIBBUILD2_SYMEXPORT const target* search_existing (const prerequisite&); // As above but cache a target searched in a custom way. // const target& search_custom (const prerequisite&, const target&); // As above but specify the prerequisite to search as a key. // LIBBUILD2_SYMEXPORT const target& search (const target&, const prerequisite_key&); LIBBUILD2_SYMEXPORT const target* search_existing (const prerequisite_key&); // Uniform search interface for prerequisite/prerequisite_member. // inline const target& search (const target& t, const prerequisite_member& p) {return p.search (t);} // As above but override the target type. Useful for searching for // target group members where we need to search for a different // target type. // const target& search (const target&, const target_type&, const prerequisite_key&); // As above but specify the prerequisite to search as individual key // components. Scope can be NULL if the directory is absolute. // const target& search (const target&, const target_type& type, const dir_path& dir, const dir_path& out, const string& name, const string* ext = nullptr, // NULL means unspecified. const scope* = nullptr, // NULL means dir is absolute. const optional& proj = nullopt); const target* search_existing (const target_type& type, const dir_path& dir, const dir_path& out, const string& name, const string* ext = nullptr, const scope* = nullptr, const optional& proj = nullopt); // As above but specify the target type as template argument. // template const T& search (const target&, const dir_path& dir, const dir_path& out, const string& name, const string* ext = nullptr, const scope* = nullptr); // Search for a target identified by the name. The semantics is "as if" we // first created a prerequisite based on this name in exactly the same way // as the parser would and then searched based on this prerequisite. // LIBBUILD2_SYMEXPORT const target& search (const target&, name, const scope&); // Unlike the above version, this one can be called during the execute // phase. Return NULL for unknown target types. // LIBBUILD2_SYMEXPORT const target* search_existing (const name&, const scope&, const dir_path& out = dir_path ()); // Target match lock: a non-const target reference and the target::offset_* // state that has already been "achieved". Note that target::task_count // itself is set to busy for the duration or the lock. While at it we also // maintain a stack of active locks in the current dependency chain (used to // detect dependency cycles). // struct LIBBUILD2_SYMEXPORT target_lock { using action_type = build2::action; using target_type = build2::target; action_type action; target_type* target = nullptr; size_t offset = 0; explicit operator bool () const {return target != nullptr;} void unlock (); // Movable-only type with move-assignment only to NULL lock. // target_lock () = default; target_lock (target_lock&&); target_lock& operator= (target_lock&&); target_lock (const target_lock&) = delete; target_lock& operator= (const target_lock&) = delete; // Implementation details. // ~target_lock (); target_lock (action_type, target_type*, size_t); struct data { action_type action; target_type* target; size_t offset; }; data release (); // Tip of the stack. // static const target_lock* stack () noexcept; // Set the new and return the previous tip of the stack. // static const target_lock* stack (const target_lock*) noexcept; const target_lock* prev; void unstack (); struct stack_guard { explicit stack_guard (const target_lock* s): s_ (stack (s)) {} ~stack_guard () {stack (s_);} const target_lock* s_; }; }; // If this target is already locked in this dependency chain, then return // the corresponding lock. Return NULL otherwise (so can be used a boolean // predicate). // const target_lock* dependency_cycle (action, const target&); // If the target is already applied (for this action) or executed, then no // lock is acquired. Otherwise, the target must not yet be matched for this // action. // // @@ MT fuzzy: what if it is already in the desired state, why assert? // Currently we only use it with match_recipe() and if it is matched // but not applied, then it's not clear why we are overriding that // match. // target_lock lock (action, const target&); // Add an ad hoc member to the end of the chain assuming that an already // existing member of this target type is the same. Return the newly added // or already existing target. The member directories (dir and out) are // expected to be absolute and normalized. // // Note that here and in find_adhoc_member() below (as well as in // perform_clean_extra()) we use target type (as opposed to, say, type and // name) as the member's identity. This fits our current needs where every // (rule-managed) ad hoc member has a unique target type and we have no need // for multiple members of the same type. This also allows us to support // things like changing the ad hoc member name by declaring it in a // buildfile. // LIBBUILD2_SYMEXPORT target& add_adhoc_member (target&, const target_type&, const dir_path& dir, const dir_path& out, string name); // If the extension is specified then it is added to the member's target // name. // target& add_adhoc_member (target&, const target_type&, const char* ext = nullptr); template inline T& add_adhoc_member (target& g, const target_type& tt, const char* e = nullptr) { return static_cast (add_adhoc_member (g, tt, e)); } template inline T& add_adhoc_member (target& g, const char* e = nullptr) { return add_adhoc_member (g, T::static_type, e); } // Find an ad hoc member of the specified target type returning NULL if not // found. // target* find_adhoc_member (target&, const target_type&); const target* find_adhoc_member (const target&, const target_type&); template inline T* find_adhoc_member (target& g, const target_type& tt) { return static_cast (find_adhoc_member (g, tt)); } template inline const T* find_adhoc_member (const target& g, const target_type& tt) { return static_cast (find_adhoc_member (g, tt)); } template inline const T* find_adhoc_member (const target& g) { return find_adhoc_member (g, T::static_type); } template inline T* find_adhoc_member (target& g) { return find_adhoc_member (g, T::static_type); } // Match and apply a rule to the action/target with ambiguity detection. // Increment the target's dependents count, which means that you should call // this function with the intent to also call execute(). Return the target // state translating target_state::failed to the failed exception unless // instructed otherwise. // // The try_match() version doesn't issue diagnostics if there is no rule // match (but fails as match() for all other errors, like rule ambiguity, // inability to apply, etc). The first half of the result indicated whether // there was a rule match. // // The unmatch argument allows optimizations that avoid calling execute(). // If it is unmatch::unchanged then only unmatch the target if it is known // to be unchanged after match. If it is unmatch::safe, then unmatch the // target if it is safe (this includes unchanged or if we know that someone // else will execute this target). Return true if unmatch succeeded. Always // throw if failed. // enum class unmatch {none, unchanged, safe}; target_state match (action, const target&, bool fail = true); pair try_match (action, const target&, bool fail = true); bool match (action, const target&, unmatch); // Start asynchronous match. Return target_state::postponed if the // asynchrounous operation has been started and target_state::busy if the // target has already been busy. Regardless of the result, match() must be // called in order to complete the operation (except target_state::failed). // // If fail is false, then return target_state::failed if the target match // failed. Otherwise, throw the failed exception if keep_going is false and // return target_state::failed otherwise. // target_state match_async (action, const target&, size_t start_count, atomic_count& task_count, bool fail = true); // Match by specifying the recipe directly and without incrementing the // dependency counts. The target must be locked. // void match_recipe (target_lock&, recipe); // Match a "delegate rule" from withing another rules' apply() function // avoiding recursive matches (thus the third argument). Unless try_match is // true, fail if no rule is found. Otherwise return empty recipe. Note that // unlike match(), this function does not increment the dependents count and // the two rules must coordinate who is using the target's data pad and/or // prerequisite_targets. See also the companion execute_delegate(). // recipe match_delegate (action, target&, const rule&, bool try_match = false); // Match a rule for the inner operation from withing the outer rule's // apply() function. See also the companion execute_inner(). // target_state match_inner (action, const target&); bool match_inner (action, const target&, unmatch); // The standard prerequisite search and match implementations. They call // search() (unless a custom is provided) and then match() (unless custom // returned NULL) for each prerequisite in a loop omitting out of project // prerequisites for the clean operation. If this target is a member of a // group, then first do this to the group's prerequisites. // using match_search = function< prerequisite_target (action, const target&, const prerequisite&, include_type)>; void match_prerequisites (action, target&, const match_search& = nullptr); // As above but go into group members. // // Note that if we cleaning, this function doesn't go into group members, as // an optimization (the group should clean everything up). // using match_search_member = function< prerequisite_target (action, const target&, const prerequisite_member&, include_type)>; void match_prerequisite_members (action, target&, const match_search_member& = nullptr); // As above but omit prerequisites that are not in the specified scope. // void match_prerequisites (action, target&, const scope&); void match_prerequisite_members (action, target&, const scope&); // Match (already searched) members of a group or similar prerequisite-like // dependencies. Similar in semantics to match_prerequisites(). Any marked // target pointers are skipped. // // T can only be const target* or prerequisite_target. // template void match_members (action, target&, T const*, size_t); template inline void match_members (action a, target& t, const target* (&ts)[N]) { match_members (a, t, ts, N); } inline void match_members (action a, target& t, prerequisite_targets& ts, size_t start = 0) { match_members (a, t, ts.data () + start, ts.size () - start); } // Unless already known, match, and, if necessary, execute the group in // order to resolve its members list. Note that even after that the member's // list might still not be available (e.g., if some wildcard/ fallback rule // matched). // // If the action is for an outer operation, then it is changed to inner // which means the members are always resolved by the inner (e.g., update) // rule. This feels right since this is the rule that will normally do the // work (e.g., update) and therefore knows what it will produce (and if we // don't do this, then the group resolution will be racy since we will use // two different task_count instances for synchronization). // LIBBUILD2_SYMEXPORT group_view resolve_members (action, const target&); // Unless already known, match the target in order to resolve its group. // // Unlike the member case, a rule can only decide whether a target is a // member of the group in its match() since otherwise it (presumably) should // not match (and some other rule may). // // If the action is for an outer operation, then it is changed to inner, the // same as for members. // const target* resolve_group (action, const target&); // Inject dependency on the target's directory fsdir{}, unless it is in the // src tree or is outside of any project (say, for example, an installation // directory). If the parent argument is true, then inject the parent // directory of a target that is itself a directory (name is empty). Return // the injected target or NULL. Normally this function is called from the // rule's apply() function. // // As an extension, this function will also search for an existing fsdir{} // prerequisite for the directory and if one exists, return that (even if // the target is in src tree). This can be used, for example, to place // output into an otherwise non-existent directory. // LIBBUILD2_SYMEXPORT const fsdir* inject_fsdir (action, target&, bool parent = true); // Execute the action on target, assuming a rule has been matched and the // recipe for this action has been set. This is the synchrounous executor // implementation (but may still return target_state::busy if the target // is already being executed). Decrements the dependents count. // // Note: does not translate target_state::failed to the failed exception. // target_state execute (action, const target&); // As above but wait for completion if the target is busy and translate // target_state::failed to the failed exception. // target_state execute_wait (action, const target&); // As above but start asynchronous execution. Return target_state::unknown // if the asynchrounous execution has been started and target_state::busy if // the target has already been busy. // // If fail is false, then return target_state::failed if the target match // failed. Otherwise, throw the failed exception if keep_going is false and // return target_state::failed otherwise. // target_state execute_async (action, const target&, size_t start_count, atomic_count& task_count, bool fail = true); // Execute the recipe obtained with match_delegate(). Note that the target's // state is neither checked nor updated by this function. In other words, // the appropriate usage is to call this function from another recipe and to // factor the obtained state into the one returned. // target_state execute_delegate (const recipe&, action, const target&); // Execute the inner operation matched with match_inner(). Note that the // returned target state is for the inner operation. The appropriate usage // is to call this function from the outer operation's recipe and to factor // the obtained state into the one returned (similar to how we do it for // prerequisites). // // Note: waits for the completion if the target is busy and translates // target_state::failed to the failed exception. // target_state execute_inner (action, const target&); // A special version of the above that should be used for "direct" and "now" // execution, that is, side-stepping the normal target-prerequisite // relationship (so no dependents count is decremented) and execution order // (so this function never returns the postponed target state). // // Note: waits for the completion if the target is busy and translates // target_state::failed to the failed exception. // LIBBUILD2_SYMEXPORT target_state execute_direct (action, const target&); // The default prerequisite execute implementation. Call execute_async() on // each non-ignored (non-NULL) prerequisite target in a loop and then wait // for their completion. Return target_state::changed if any of them were // changed and target_state::unchanged otherwise. If a prerequisite's // execution is postponed (and thus its state cannot be queried MT-safely) // of if the prerequisite is marked as ad hoc, then set its pointer in // prerequisite_targets to NULL. If count is not 0, then only the first // count prerequisites are executed beginning from start. // // Note that because after the call the ad hoc prerequisites are no longer // easily accessible, this function shouldn't be used in rules that make a // timestamp-based out-of-date'ness determination (which must take into // account such prerequisites). Instead, consider the below versions that // incorporate the timestamp check and do the right thing. // target_state straight_execute_prerequisites (action, const target&, size_t count = 0, size_t start = 0); // As above but iterates over the prerequisites in reverse. // target_state reverse_execute_prerequisites (action, const target&, size_t count = 0); // Call straight or reverse depending on the current mode. // target_state execute_prerequisites (action, const target&, size_t count = 0); // As above but execute prerequisites for the inner action (that have // been matched with match_inner()). // target_state straight_execute_prerequisites_inner (action, const target&, size_t count = 0, size_t start = 0); target_state reverse_execute_prerequisites_inner (action, const target&, size_t count = 0); target_state execute_prerequisites_inner (action, const target&, size_t count = 0); // A version of the above that also determines whether the action needs to // be executed on the target based on the passed timestamp and filter. If // count is not 0, then only the first count prerequisites are executed. // // The filter is passed each prerequisite target and is expected to signal // which ones should be used for timestamp comparison. If the filter is // NULL, then all the prerequisites are used. Note that ad hoc prerequisites // are always used. // // Note that the return value is an optional target state. If the target // needs updating, then the value is absent. Otherwise it is the state that // should be returned. This is used to handle the situation where some // prerequisites were updated but no update of the target is necessary. In // this case we still signal that the target was (conceptually, but not // physically) changed. This is important both to propagate the fact that // some work has been done and to also allow our dependents to detect this // case if they are up to something tricky (like recursively linking liba{} // prerequisites). // // Note that because we use mtime, this function should normally only be // used in the perform_update action (which is straight). // using execute_filter = function; optional execute_prerequisites (action, const target&, const timestamp&, const execute_filter& = nullptr, size_t count = 0); // Another version of the above that does two extra things for the caller: // it determines whether the action needs to be executed on the target based // on the passed timestamp and finds a prerequisite of the specified type // (e.g., a source file). If there are multiple prerequisites of this type, // then the first is returned (this can become important if additional // prerequisites of the same type get injected). // template pair, const T&> execute_prerequisites (action, const target&, const timestamp&, const execute_filter& = nullptr, size_t count = 0); pair, const target&> execute_prerequisites (const target_type&, action, const target&, const timestamp&, const execute_filter& = nullptr, size_t count = 0); template pair, const T&> execute_prerequisites (const target_type&, action, const target&, const timestamp&, const execute_filter& = nullptr, size_t count = 0); // Execute members of a group or similar prerequisite-like dependencies. // Similar in semantics to execute_prerequisites(). // // T can only be const target* or prerequisite_target. If it is the latter, // the ad hoc blank out semantics described in execute_prerequsites() is in // effect. // template target_state straight_execute_members (action, atomic_count&, T[], size_t, size_t); template target_state reverse_execute_members (action, atomic_count&, T[], size_t, size_t); template inline target_state straight_execute_members (action a, const target& t, T ts[], size_t c, size_t s) { return straight_execute_members (a, t[a].task_count, ts, c, s); } template inline target_state reverse_execute_members (action a, const target& t, T ts[], size_t c, size_t s) { return reverse_execute_members (a, t[a].task_count, ts, c, s); } // Call straight or reverse depending on the current mode. // target_state execute_members (action, const target&, const target*[], size_t); template inline target_state straight_execute_members (action a, const target& t, const target* (&ts)[N]) { return straight_execute_members (a, t, ts, N, 0); } template inline target_state reverse_execute_members (action a, const target& t, const target* (&ts)[N]) { return reverse_execute_members (a, t, ts, N, N); } template inline target_state execute_members (action a, const target& t, const target* (&ts)[N]) { return execute_members (a, t, ts, N); } // Return noop_recipe instead of using this function directly. // LIBBUILD2_SYMEXPORT target_state noop_action (action, const target&); // Default action implementation which forwards to the prerequisites. // Use default_recipe instead of using this function directly. // LIBBUILD2_SYMEXPORT target_state default_action (action, const target&); // Standard perform(clean) action implementation for the file target // (or derived). // LIBBUILD2_SYMEXPORT target_state perform_clean (action, const target&); // As above, but also removes the auxiliary dependency database (.d file). // LIBBUILD2_SYMEXPORT target_state perform_clean_depdb (action, const target&); // As above but clean the target group. The group should be an mtime_target // and members should be files. // LIBBUILD2_SYMEXPORT target_state perform_clean_group (action, const target&); // As above but clean both the target group and depdb. The depdb file path // is derived from the first member file path. // LIBBUILD2_SYMEXPORT target_state perform_clean_group_depdb (action, const target&); // Helper for custom perform(clean) implementations that cleans extra files // and directories (recursively) specified as a list of either absolute // paths or "path derivation directives". The directive string can be NULL, // or empty in which case it is ignored. If the last character in a // directive is '/', then the resulting path is treated as a directory // rather than a file. The directive can start with zero or more '-' // characters which indicate the number of extensions that should be // stripped before the new extension (if any) is added (so if you want to // strip the extension, specify just "-"). For example: // // perform_clean_extra (a, t, {".d", ".dlls/", "-.dll"}); // // The extra files/directories are removed first in the specified order // followed by the ad hoc group member, then target itself, and, finally, // the prerequisites in the reverse order. // // You can also clean extra files derived from ad hoc group members that are // "indexed" using using their target types (see add/find_adhoc_member() for // details). // // Note that if the target path is empty then it is assumed "unreal" and is // not cleaned (but its prerequisites/members still are). // using clean_extras = small_vector; struct clean_adhoc_extra { const target_type& type; clean_extras extras; }; using clean_adhoc_extras = small_vector; LIBBUILD2_SYMEXPORT target_state perform_clean_extra (action, const file&, const clean_extras&, const clean_adhoc_extras& = {}); inline target_state perform_clean_extra (action a, const file& f, initializer_list e) { return perform_clean_extra (a, f, clean_extras (e)); } // Update/clean a backlink issuing appropriate diagnostics at appropriate // levels depending on the overload and the changed argument. // enum class backlink_mode { link, // Make a symbolic link if possible, hard otherwise. symbolic, // Make a symbolic link. hard, // Make a hard link. copy, // Make a copy. overwrite // Copy over but don't remove on clean (committed gen code). }; LIBBUILD2_SYMEXPORT void update_backlink (const file& target, const path& link, bool changed, backlink_mode = backlink_mode::link); LIBBUILD2_SYMEXPORT void update_backlink (const path& target, const path& link, bool changed, backlink_mode = backlink_mode::link); LIBBUILD2_SYMEXPORT void update_backlink (const path& target, const path& link, backlink_mode = backlink_mode::link); LIBBUILD2_SYMEXPORT void clean_backlink (const path& link, uint16_t verbosity, backlink_mode = backlink_mode::link); } #include #endif // LIBBUILD2_ALGORITHM_HXX