Systemtap: Restore public TapsetLibrary.init().

Restore the public initialization method for TapsetLibrary,
so that tapset contents can be loaded as soon as the Systemtap
plugin is loaded. Also implement a better means of forbidding
multiple initializations than what was done before.

Resolves EBZ #436169.

Change-Id: I7a771c78698d32cb24f94403fb4f9c648085a5b6
Signed-off-by: Andrew Ferrazzutti <aferrazz@redhat.com>
Reviewed-on: https://git.eclipse.org/r/27533
Tested-by: Hudson CI
Reviewed-by: Jeff Johnston <jjohnstn@redhat.com>
Tested-by: Jeff Johnston <jjohnstn@redhat.com>

2 files changed, 23 insertions, 17 deletions

diff --git a/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/IDEPlugin.java b/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/IDEPlugin.java
index bf9eeea4c0..6510dfd054 100644
--- a/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/IDEPlugin.java
+++ b/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/IDEPlugin.java
@@ -55,6 +55,7 @@ public class IDEPlugin extends AbstractUIPlugin {
 
         workbenchListener = new IDECloseMonitor();
         plugin.getWorkbench().addWorkbenchListener(workbenchListener);
+        TapsetLibrary.init();
     }
 
     /**
diff --git a/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/structures/TapsetLibrary.java b/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/structures/TapsetLibrary.java
index 833722a394..8cdcc4c87e 100644
--- a/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/structures/TapsetLibrary.java
+++ b/systemtap/org.eclipse.linuxtools.systemtap.ui.ide/src/org/eclipse/linuxtools/internal/systemtap/ui/ide/structures/TapsetLibrary.java
@@ -50,6 +50,8 @@ public final class TapsetLibrary {
     private static final IUpdateListener functionCompletionListener = new ParseCompletionListener(functionParser);
     private static final IUpdateListener probeCompletionListener = new ParseCompletionListener(probeParser);
 
+    private static boolean initialized = false;
+
     public static TreeNode getProbes() {
         return probeTree;
     }
@@ -139,19 +141,26 @@ public final class TapsetLibrary {
         return documentation;
     }
 
-    private static void init() {
-        IPreferenceStore preferenceStore = IDEPlugin.getDefault().getPreferenceStore();
-        preferenceStore.addPropertyChangeListener(propertyChangeListener);
-        ConsoleLogPlugin.getDefault().getPreferenceStore().addPropertyChangeListener(credentialChangeListener);
-
-        functionParser.addListener(functionCompletionListener);
-        probeParser.addListener(probeCompletionListener);
-
-        if (preferenceStore.getBoolean(IDEPreferenceConstants.P_STORED_TREE)
-                && isTreeFileCurrent()) {
-            readTreeFile();
-        } else {
-            runStapParser();
+    /**
+     * Initialize all listeners associated with loading tapset contents, and perform
+     * the first tapset load operation. Note that subsequent calls to this method will have no effect.
+     */
+    public synchronized static void init() {
+        if (!initialized) {
+            initialized = true;
+            IPreferenceStore preferenceStore = IDEPlugin.getDefault().getPreferenceStore();
+            preferenceStore.addPropertyChangeListener(propertyChangeListener);
+            ConsoleLogPlugin.getDefault().getPreferenceStore().addPropertyChangeListener(credentialChangeListener);
+
+            functionParser.addListener(functionCompletionListener);
+            probeParser.addListener(probeCompletionListener);
+
+            if (preferenceStore.getBoolean(IDEPreferenceConstants.P_STORED_TREE)
+                    && isTreeFileCurrent()) {
+                readTreeFile();
+            } else {
+                runStapParser();
+            }
         }
     }
 
@@ -448,8 +457,4 @@ public final class TapsetLibrary {
             cacheProbeManpages.join();
         } catch (InterruptedException e) {}
     }
-
-    static {
-        init();
-    }
 }