Added installed lib priority comparator

This clearly defines the usage priority for installed libraries.

arduino-core/src/cc/arduino/contributions/libraries/LibrariesIndexer.java

@@ -43,6 +43,7 @@ import processing.app.packages.LibraryList;
 import processing.app.packages.UserLibrary;
 import processing.app.packages.UserLibraryFolder;
 import processing.app.packages.UserLibraryFolder.Location;
+import processing.app.packages.UserLibraryPriorityComparator;
 
 import java.io.File;
 import java.io.FileInputStream;
@@ -111,7 +112,25 @@ public class LibrariesIndexer {
     return librariesFolders;
   }
 
+  private UserLibraryPriorityComparator priorityComparator;
+
+  public void addToInstalledLibraries(UserLibrary lib) {
+    UserLibrary toReplace = installedLibraries.getByName(lib.getName());
+    if (toReplace == null) {
+      installedLibraries.add(lib);
+      return;
+    }
+    if (priorityComparator.compare(toReplace, lib) >= 0) {
+      // The current lib has priority, do nothing
+      return;
+    }
+    installedLibraries.remove(toReplace);
+    installedLibraries.add(lib);
+  }
+
   public void rescanLibraries() {
+    priorityComparator = new UserLibraryPriorityComparator(BaseNoGui.getTargetPlatform().getId());
+
     // Clear all installed flags
     installedLibraries.clear();
 
@@ -180,7 +199,7 @@ public class LibrariesIndexer {
       if (headers.length == 0) {
         throw new IOException(lib.getSrcFolder().getAbsolutePath());
       }
-      installedLibraries.addOrReplace(lib);
+      addToInstalledLibraries(lib);
       return;
     }
 
@@ -190,7 +209,7 @@ public class LibrariesIndexer {
     if (headers.length == 0) {
       throw new IOException(lib.getSrcFolder().getAbsolutePath());
     }
-    installedLibraries.addOrReplaceArchAware(lib);
+    addToInstalledLibraries(lib);
 
     Location loc = lib.getLocation();
     if (loc != Location.CORE && loc != Location.REFERENCED_CORE) {

arduino-core/src/processing/app/packages/LibraryList.java

@@ -57,27 +57,6 @@ public class LibraryList extends LinkedList<UserLibrary> {
     return null;
   }
 
-  public synchronized void addOrReplaceArchAware(UserLibrary lib) {
-    addOrReplace(lib, true);
-  }
-
-  public synchronized void addOrReplace(UserLibrary lib) {
-    addOrReplace(lib, false);
-  }
-
-  public synchronized void addOrReplace(UserLibrary lib, boolean archAware) {
-    remove(lib, archAware);
-    add(lib);
-  }
-
-  public synchronized void remove(UserLibrary lib, boolean archAware) {
-    UserLibrary l = getByName(lib.getName());
-    if (l != null) {
-      if (!archAware || lib.getArchitectures().contains("*") || lib.getArchitectures().containsAll(l.getArchitectures()))
-        super.remove(l);
-    }
-  }
-
   public synchronized void sort() {
     Collections.sort(this, (x, y) -> x.getName().compareToIgnoreCase(y.getName()));
   }

arduino-core/src/processing/app/packages/UserLibraryPriorityComparator.java

@@ -0,0 +1,71 @@
+/*
+ * This file is part of Arduino.
+ *
+ * Copyright 2017 Arduino LLC (http://www.arduino.cc/)
+ *
+ * Arduino is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ */
+package processing.app.packages;
+
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+
+import processing.app.packages.UserLibraryFolder.Location;
+
+public class UserLibraryPriorityComparator implements Comparator<UserLibrary> {
+
+  private final static Map<Location, Integer> priorities = new HashMap<>();
+  static {
+    priorities.put(Location.SKETCHBOOK, 4);
+    priorities.put(Location.CORE, 3);
+    priorities.put(Location.REFERENCED_CORE, 2);
+    priorities.put(Location.IDE_BUILTIN, 1);
+  }
+
+  private String arch;
+
+  public UserLibraryPriorityComparator(String currentArch) {
+    arch = currentArch;
+  }
+
+  private boolean hasArchitecturePriority(UserLibrary x) {
+    return x.getArchitectures().contains(arch);
+  }
+
+  public int priority(UserLibrary l) {
+    int priority = priorities.get(l.getLocation());
+    if (hasArchitecturePriority(l))
+      priority += 10;
+    return priority;
+  }
+
+  @Override
+  public int compare(UserLibrary x, UserLibrary y) {
+    if (!x.getName().equals(y.getName())) {
+      throw new IllegalArgumentException("The compared libraries must have the same name");
+    }
+    return priority(x) - priority(y);
+  }
+}