From 1397444e5de3281431d2174564dfd76fe7b7b32f Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 21 Apr 2016 07:19:03 +0200
Subject: Use hash map/set for targets/prerequisites to resolve key change
 issue

---
 build2/target-key | 64 ++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 42 insertions(+), 22 deletions(-)

(limited to 'build2/target-key')

diff --git a/build2/target-key b/build2/target-key
index 2c0d0f2..c911a1f 100644
--- a/build2/target-key
+++ b/build2/target-key
@@ -6,6 +6,7 @@
 #define BUILD2_TARGET_KEY
 
 #include <map>
+#include <functional> // hash
 
 #include <butl/utility> // compare_c_string
 
@@ -25,30 +26,26 @@ namespace build2
     const dir_path* const dir; // Can be relative if part of prerequisite_key.
     const dir_path* const out; // Can be relative if part of prerequisite_key.
     const string* const  name;
-    const string* const& ext;
-
-    friend bool
-    operator< (const target_key& x, const target_key& y)
-    {
-      const target_type* xt (x.type);
-      const target_type* yt (y.type);
-
-      int t, n, d, o;
-
-      // Unspecified and specified extension are assumed equal. The
-      // extension strings are from the pool, so we can just compare
-      // pointers.
-      //
-      return
-        ((t = xt < yt ? -1 : xt > yt ? 1 : 0) < 0) ||
-        (t == 0 && (n = x.name->compare (*y.name)) < 0) ||
-        (t == 0 &&  n == 0 && (d = x.dir->compare (*y.dir)) < 0) ||
-        (t == 0 &&  n == 0 &&  d == 0 && (o = x.out->compare (*y.out)) < 0) ||
-        (t == 0 &&  n == 0 &&  d == 0 &&  o == 0 &&
-         x.ext != nullptr && y.ext != nullptr && *x.ext < *y.ext);
-    }
+    const string* const& ext; //@@ Iffy, whan happens when move/copy?
   };
 
+  inline bool
+  operator== (const target_key& x, const target_key& y)
+  {
+    // Unspecified and specified extension are assumed equal. The extension
+    // strings are from the pool, so we can just compare pointers.
+    //
+    return
+      x.type == y.type &&
+      *x.dir == *y.dir &&
+      *x.out == *y.out &&
+      *x.name == *y.name &&
+      (x.ext == nullptr || y.ext == nullptr || x.ext == y.ext);
+  }
+
+  inline bool
+  operator!= (const target_key& x, const target_key& y) {return !(x == y);}
+
   // If the target type has a custom print function, call that. Otherwise,
   // call to_stream() with the current stream verbosity as a third argument.
   // Both are defined in target.cxx.
@@ -60,4 +57,27 @@ namespace build2
   to_stream (ostream&, const target_key&, uint16_t ext_verb);
 }
 
+namespace std
+{
+  // Note that we ignore the extension when calculating the hash because of
+  // its special "unspecified" logic (see operator== above).
+  //
+  template <>
+  struct hash<build2::target_key>
+  {
+    using argument_type = build2::target_key;
+    using result_type = size_t;
+
+    size_t
+    operator() (const build2::target_key& k) const noexcept
+    {
+      return build2::combine_hash (
+        hash<const build2::target_type*> () (k.type),
+        hash<build2::dir_path> () (*k.dir),
+        hash<build2::dir_path> () (*k.out),
+        hash<string> () (*k.name));
+    }
+  };
+}
+
 #endif // BUILD2_TARGET_KEY
-- 
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