Reusing libraries inside Library#library_from_file and Library#library:from_files for conservative reloading.

src/db/db/dbFileBasedLibrary.cc

@@ -53,6 +53,27 @@ FileBasedLibrary::merge_with_other_layout (const std::string &path)
   }
 }
 
+bool
+FileBasedLibrary::is_for_path (const std::string &path)
+{
+  return m_other_paths.empty () && m_path == path;
+}
+
+bool
+FileBasedLibrary::is_for_paths (const std::vector<std::string> &paths)
+{
+  if (paths.size () != m_other_paths.size () + 1) {
+    return false;
+  }
+
+  //  this check is purely based on path strings
+  std::set<std::string> p1 (paths.begin (), paths.end ());
+  std::set<std::string> p2;
+  p2.insert (m_path);
+  p2.insert (m_other_paths.begin (), m_other_paths.end ());
+  return p1 == p2;
+}
+
 std::string
 FileBasedLibrary::load ()
 {

src/db/db/dbFileBasedLibrary.h

@@ -89,6 +89,16 @@ public:
     m_other_paths = other_paths;
   }
 
+  /**
+   *  @brief Gets a value indicating whether the library is for the given path
+   */
+  bool is_for_path (const std::string &path);
+
+  /**
+   *  @brief Gets a value indicating whether the library is for the given path
+   */
+  bool is_for_paths (const std::vector<std::string> &paths);
+
 private:
   std::string m_name;
   std::string m_path;

src/db/db/gsiDeclDbLibrary.cc

@@ -157,9 +157,21 @@ static LibraryImpl *new_lib ()
   return new LibraryImpl ();
 }
 
-static db::Library *library_from_file (const std::string &path, const std::string &name)
+static db::Library *library_from_file (const std::string &path, const std::string &name, const std::string &for_technology)
 {
+  //  Check if a library with this specification already is installed and reuse in that case.
+  if (! name.empty ()) {
+
+    db::FileBasedLibrary *old_lib = dynamic_cast<db::FileBasedLibrary *> (library_by_name (name, for_technology));
+    if (old_lib && old_lib->is_for_path (path)) {
+      old_lib->load ();
+      return old_lib;
+    }
+
+  }
+
   std::unique_ptr<db::FileBasedLibrary> lib (new db::FileBasedLibrary (path, name));
+  lib->set_technology (for_technology);
 
   std::string n = lib->load ();
   db::Library *ret = lib.get ();
@@ -168,17 +180,30 @@ static db::Library *library_from_file (const std::string &path, const std::strin
   return ret;
 }
 
-static  db::Library *library_from_files (const std::vector<std::string> &paths, const std::string &name)
+static  db::Library *library_from_files (const std::vector<std::string> &paths, const std::string &name, const std::string &for_technology)
 {
   if (paths.empty ()) {
     throw tl::Exception (tl::to_string (tr ("At least one path must be given")));
   }
 
+  //  Check if a library with this specification already is installed and reuse in that case.
+  if (! name.empty ()) {
+
+    db::FileBasedLibrary *old_lib = dynamic_cast<db::FileBasedLibrary *> (library_by_name (name, for_technology));
+    if (old_lib && old_lib->is_for_paths (paths)) {
+      old_lib->load ();
+      return old_lib;
+    }
+
+  }
+
   std::unique_ptr<db::FileBasedLibrary> lib (new db::FileBasedLibrary (paths.front (), name));
   for (auto i = paths.begin () + 1; i != paths.end (); ++i) {
     lib->merge_with_other_layout (*i);
   }
 
+  lib->set_technology (for_technology);
+
   std::string n = lib->load ();
   db::Library *ret = lib.get ();
   register_lib (lib.release (), n);
@@ -191,7 +216,7 @@ static  db::Library *library_from_files (const std::vector<std::string> &paths,
  */
 
 LibraryClass<db::Library> decl_Library ("db", "LibraryBase",
-  gsi::method ("library_from_file", &library_from_file, gsi::arg ("path"), gsi::arg ("name", std::string (), "auto"),
+  gsi::method ("library_from_file", &library_from_file, gsi::arg ("path"), gsi::arg ("name", std::string (), "auto"), gsi::arg ("for_technology", std::string (), "none"),
     "@brief Creates a library from a file\n"
     "@param path The path to the file from which to create the library from.\n"
     "@param name The name of the library. If empty, the name will be derived from the GDS LIBNAME or the file name.\n"
@@ -200,9 +225,12 @@ LibraryClass<db::Library> decl_Library ("db", "LibraryBase",
     "This method will create a \\Library object which is tied to a specific file. This object supports "
     "automatic reloading when the \\Library#refresh method is called.\n"
     "\n"
+    "If a file-based library with the same name and path is registered already, this method will not reload again "
+    "and return the library that was already registered.\n"
+    "\n"
     "This convenience method has been added in version 0.30.8.\n"
   ) +
-  gsi::method ("library_from_files", &library_from_files, gsi::arg ("paths"), gsi::arg ("name", std::string (), "auto"),
+  gsi::method ("library_from_files", &library_from_files, gsi::arg ("paths"), gsi::arg ("name", std::string (), "auto"), gsi::arg ("for_technology", std::string (), "none"),
     "@brief Creates a library from a set of files\n"
     "@param paths The paths to the files from which to create the library from. At least one file needs to be given.\n"
     "@param name The name of the library. If empty, the name will be derived from the GDS LIBNAME or the file name.\n"