Simplify version comparison

5 files changed, 65 insertions, 60 deletions

diff --git a/brep/package b/brep/package
index 6ca0c12..6cd87e9 100644
--- a/brep/package
+++ b/brep/package
@@ -68,6 +68,30 @@ namespace brep
   //    to TEXT as a comma-separated list.
   //
 
+  // Version comparison operators.
+  //
+  template <typename T1, typename T2>
+  inline auto
+  operator< (const T1& x, const T2& y) -> decltype (x.epoch < y.epoch)
+  {
+    return x.epoch < y.epoch ||
+                     (x.epoch == y.epoch &&
+                      x.canonical_upstream < y.canonical_upstream) ||
+      (x.epoch == y.epoch &&
+       x.canonical_upstream == y.canonical_upstream &&
+       x.revision < y.revision);
+  }
+
+  template <typename T>
+  inline auto
+  order_by_version_desc (const T& x) -> decltype (x.epoch == 0)
+  {
+    return "ORDER BY"
+      + x.epoch + "DESC,"
+      + x.canonical_upstream + "DESC,"
+      + x.revision + "DESC";
+  }
+
   // Forward declarations.
   //
   class repository;
@@ -109,9 +133,16 @@ namespace brep
   struct package_version_id
   {
     std::string package;
-    std::uint16_t epoch;
-    std::string canonical_upstream;
-    std::uint16_t revision;
+
+    #pragma db value
+    struct version_type
+    {
+      std::uint16_t epoch;
+      std::string canonical_upstream;
+      std::uint16_t revision;
+    };
+
+    version_type version;
 
     // Database mapping.
     //
@@ -126,15 +157,7 @@ namespace brep
     if (r != 0)
       return r < 0;
 
-    if (x.epoch != y.epoch)
-      return x.epoch < y.epoch;
-
-    r = x.canonical_upstream.compare (y.canonical_upstream);
-
-    if (r != 0)
-      return r < 0;
-
-    return x.revision < y.revision;
+    return x.version < y.version;
   }
 
   using priority = bpkg::priority;
@@ -458,10 +481,9 @@ namespace brep
     package_version () = default;
   };
 
-  #pragma db view object(package_version)                               \
-    query((?) + "ORDER BY" + package_version::id.data.epoch + "DESC," + \
-          package_version::id.data.canonical_upstream + "DESC," +       \
-          package_version::id.data.revision + "DESC LIMIT 1")
+  #pragma db view object(package_version)                                  \
+    query((?) + order_by_version_desc (package_version::id.data.version) + \
+          "LIMIT 1")
   struct max_package_version
   {
     using version_type = brep::version;
@@ -486,13 +508,7 @@ namespace brep
   #pragma db view object(package_version = version)                    \
     object(package_version = v:                                        \
            version::id.data.package == v::id.data.package &&           \
-           (version::id.data.epoch < v::id.data.epoch ||               \
-            (version::id.data.epoch == v::id.data.epoch &&             \
-             (version::id.data.canonical_upstream <                    \
-              v::id.data.canonical_upstream ||                         \
-              (version::id.data.canonical_upstream ==                  \
-               v::id.data.canonical_upstream &&                        \
-               version::id.data.revision < v::id.data.revision)))))    \
+           version::id.data.version < v::id.data.version)              \
     object(package inner: version::id.data.package == package::name && \
            version::internal_repository.is_not_null () &&              \
            v::id.data.package.is_null ())
@@ -521,6 +537,12 @@ namespace brep
   };
 }
 
+namespace odb
+{
+  using ::brep::operator<;
+  using ::brep::order_by_version_desc;
+}
+
 // Nested container emulation support for ODB.
 //
 // Note that the outer index in the inner container should strictly
diff --git a/brep/package-version-search.cxx b/brep/package-version-search.cxx
index 166f116..2774a16 100644
--- a/brep/package-version-search.cxx
+++ b/brep/package-version-search.cxx
@@ -149,9 +149,7 @@ namespace brep
       db_->query<package_version> (
         (query::id.data.package == name &&
          query::internal_repository.is_not_null ()) +
-        "ORDER BY" + query::id.data.epoch + "DESC," +
-        query::id.data.canonical_upstream + "DESC," +
-        query::id.data.revision + "DESC " +
+        order_by_version_desc (query::id.data.version) +
         "OFFSET" + to_string (pr.page () * rop) +
         "LIMIT" + to_string (rop)));
 
diff --git a/brep/package.cxx b/brep/package.cxx
index b0c1115..46953f4 100644
--- a/brep/package.cxx
+++ b/brep/package.cxx
@@ -98,9 +98,10 @@ namespace brep
   void package_version::
   _id (_id_type&& v, database& db)
   {
+    const auto& dv (v.data.version);
     package = lazy_shared_ptr<package_type> (db, v.data.package);
-    version = version_type (v.data.epoch, move (v.upstream), v.data.revision);
-    assert (version.canonical_upstream == v.data.canonical_upstream);
+    version = version_type (dv.epoch, move (v.upstream), dv.revision);
+    assert (version.canonical_upstream == dv.canonical_upstream);
   }
 
   // max_package_version
@@ -108,8 +109,9 @@ namespace brep
   void max_package_version::
   _id (package_version::_id_type&& v)
   {
-    version = version_type (v.data.epoch, move (v.upstream), v.data.revision);
-    assert (version.canonical_upstream == v.data.canonical_upstream);
+    const auto& dv (v.data.version);
+    version = version_type (dv.epoch, move (v.upstream), dv.revision);
+    assert (version.canonical_upstream == dv.canonical_upstream);
   }
 
   // repository
diff --git a/loader/loader.cxx b/loader/loader.cxx
index 3aa2b12..a901d14 100644
--- a/loader/loader.cxx
+++ b/loader/loader.cxx
@@ -406,9 +406,10 @@ load_packages (const shared_ptr<repository>& rp, database& db)
         package_version_id
         {
           pm.name,
-          pm.version.epoch,
-          pm.version.canonical_upstream,
-          pm.version.revision
+          { pm.version.epoch,
+            pm.version.canonical_upstream,
+            pm.version.revision
+          }
         }));
 
     if (pv == nullptr)
diff --git a/tests/loader/driver.cxx b/tests/loader/driver.cxx
index 4fc1333..104255a 100644
--- a/tests/loader/driver.cxx
+++ b/tests/loader/driver.cxx
@@ -131,9 +131,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libfoo",
-            fv1.epoch,
-            fv1.canonical_upstream,
-            fv1.revision}));
+            {fv1.epoch, fv1.canonical_upstream, fv1.revision}}));
       assert (check_location (fpv1));
 
       version fv2 ("1.2.2");
@@ -141,9 +139,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libfoo",
-            fv2.epoch,
-            fv2.canonical_upstream,
-            fv2.revision}));
+            {fv2.epoch, fv2.canonical_upstream, fv2.revision}}));
       assert (check_location (fpv2));
 
       version fv3 ("1.2.3-4");
@@ -151,9 +147,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libfoo",
-            fv3.epoch,
-            fv3.canonical_upstream,
-            fv3.revision}));
+            {fv3.epoch, fv3.canonical_upstream, fv3.revision}}));
       assert (check_location (fpv3));
 
       version fv4 ("1.2.4");
@@ -161,9 +155,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libfoo",
-            fv4.epoch,
-            fv4.canonical_upstream,
-            fv4.revision}));
+            {fv4.epoch, fv4.canonical_upstream, fv4.revision}}));
       assert (check_location (fpv4));
 
       version xv ("1.0.0-1");
@@ -171,9 +163,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libstudxml",
-            xv.epoch,
-            xv.canonical_upstream,
-            xv.revision}));
+            {xv.epoch, xv.canonical_upstream, xv.revision}}));
       assert (check_location (xpv));
 
       // Verify libstudxml package.
@@ -357,9 +347,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libexp",
-            ev.epoch,
-            ev.canonical_upstream,
-            ev.revision}));
+            {ev.epoch, ev.canonical_upstream, ev.revision}}));
       assert (check_location (epv));
 
       version fv5 ("1.2.4-1");
@@ -367,9 +355,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libfoo",
-            fv5.epoch,
-            fv5.canonical_upstream,
-            fv5.revision}));
+            {fv5.epoch, fv5.canonical_upstream, fv5.revision}}));
       assert (fpv[5].load () == fpv5);
       assert (check_location (fpv5));
 
@@ -504,9 +490,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libbar",
-            bv.epoch,
-            bv.canonical_upstream,
-            bv.revision}));
+            {bv.epoch, bv.canonical_upstream, bv.revision}}));
       assert (check_location (bpv));
 
       version fv0 ("0.1");
@@ -514,9 +498,7 @@ main (int argc, char* argv[])
         db.load<package_version> (
           package_version_id {
             "libfoo",
-            fv0.epoch,
-            fv0.canonical_upstream,
-            fv0.revision}));
+            {fv0.epoch, fv0.canonical_upstream, fv0.revision}}));
       assert (check_location (fpv0));
 
       // Verify libbar package.