Add ability to query whether target has been matched for action

2 files changed, 26 insertions, 3 deletions

diff --git a/libbuild2/target.hxx b/libbuild2/target.hxx
index 1abda2d..ea72925 100644
--- a/libbuild2/target.hxx
+++ b/libbuild2/target.hxx
@@ -592,7 +592,13 @@ namespace build2
     opstate&       operator[] (action a)       {return state[a];}
     const opstate& operator[] (action a) const {return state[a];}
 
-    // This function should only be called during match if we have observed
+    // Return true if the target has been matched for the specified action.
+    // This function can only be called during execution.
+    //
+    bool
+    matched (action) const;
+
+    // This function can only be called during match if we have observed
     // (synchronization-wise) that this target has been matched (i.e., the
     // rule has been applied) for this action.
     //
@@ -610,8 +616,8 @@ namespace build2
     bool
     unchanged (action) const;
 
-    // This function should only be called during execution if we have
-    // observed (synchronization-wise) that this target has been executed.
+    // This function can only be called during execution if we have observed
+    // (synchronization-wise) that this target has been executed.
     //
     target_state
     executed_state (action, bool fail = true) const;
diff --git a/libbuild2/target.ixx b/libbuild2/target.ixx
index f7896d0..3842c37 100644
--- a/libbuild2/target.ixx
+++ b/libbuild2/target.ixx
@@ -66,6 +66,22 @@ namespace build2
   }
 
   inline bool target::
+  matched (action a) const
+  {
+    assert (ctx.phase == run_phase::execute);
+
+    const opstate& s (state[a]);
+
+    // Note that while the target could be being executed, we should see at
+    // least offset_matched since it must have been "achieved" before the
+    // phase switch.
+    //
+    size_t c (s.task_count.load (memory_order_relaxed) - ctx.count_base ());
+
+    return c >= offset_matched;
+  }
+
+  inline bool target::
   group_state (action a) const
   {
     // We go an extra step and short-circuit to the target state even if the
@@ -96,6 +112,7 @@ namespace build2
     const opstate& s (state[a]);
 
     // Note: already synchronized.
+    //
     size_t o (s.task_count.load (memory_order_relaxed) - ctx.count_base ());
 
     if (o == offset_tried)