ctf: improve scope creation

Speeds up trace reading by ~5-10%. The concurrent hashmap was used to avoid
contention. But the function is stable A will always produce B. So we can use
a normal hashmap.

[Changed] speed up ctf parsing of lexical scopes

Change-Id: I75f4b68de08c43f8ccb11a6fb6cc19c2e7d02f1e
Signed-off-by: Matthew Khouzam <[email protected]>

Author: MatthewKhouzam

ctf/org.eclipse.tracecompass.ctf.core/src/org/eclipse/tracecompass/ctf/core/event/scope/LexicalScope.java

@@ -13,8 +13,8 @@
 
 package org.eclipse.tracecompass.ctf.core.event.scope;
 
+import java.util.HashMap;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
 
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
@@ -28,7 +28,7 @@ public class LexicalScope implements ILexicalScope {
     private int hash = 0;
     private final @NonNull String fName;
     private final @NonNull String fPath;
-    private final Map<String, ILexicalScope> fChildren = new ConcurrentHashMap<>();
+    private final Map<String, ILexicalScope> fChildren = new HashMap<>();
 
     /**
      * Hidden constructor for the root node only
@@ -40,6 +40,22 @@ protected LexicalScope() {
         fName = ""; //$NON-NLS-1$
     }
 
+    /**
+     * Create a scope
+     * @param parent
+     *            The parent node, can be null, but shouldn't
+     * @param name
+     *            the name of the field
+     * @return the scope
+     */
+    public static @NonNull ILexicalScope create(ILexicalScope parent, @NonNull String name) {
+        ILexicalScope child = parent.getChild(name);
+        if( child == null) {
+            child = new LexicalScope(parent, name);
+        }
+        return child;
+    }
+
     /**
      * The scope constructor
      *

ctf/org.eclipse.tracecompass.ctf.core/src/org/eclipse/tracecompass/ctf/core/event/types/Declaration.java

@@ -43,18 +43,10 @@ public ILexicalScope getPath(IDefinitionScope definitionScope, @NonNull String f
         if (definitionScope != null) {
             final ILexicalScope parentPath = definitionScope.getScopePath();
             if (parentPath != null) {
-                ILexicalScope myScope = parentPath.getChild(fieldName);
-                if (myScope == null) {
-                    myScope = new LexicalScope(parentPath, fieldName);
-                }
-                return myScope;
+                return LexicalScope.create(parentPath, fieldName);
             }
         }
-        ILexicalScope child = ILexicalScope.ROOT.getChild(fieldName);
-        if (child != null) {
-            return child;
-        }
-        return new LexicalScope(ILexicalScope.ROOT, fieldName);
+        return LexicalScope.create(ILexicalScope.ROOT, fieldName);
     }
 
     /**