Bug 521515: Do not log every failed access attempt

The Windows registry can be checked for keys that may not exist.
In order to avoid logging an exception that the entry is missing when
it's not critical that the entry do exist, the method should just return
null and let the caller handle if it's critical or not that the entry
exists. To easily debug situations where the entry is supposed to always
exist, the trace symbol
"org.eclipse.cdt.core.native/debug/win32/registry" can be set to "true"
and the exceptions will be logged in any case.

Change-Id: I6603cbe363ebecd357fa44c41fb1a26c6345dd70
Signed-off-by: Torbjörn Svensson <azoff@svenskalinuxforeningen.se>

Author: T-Svensson

core/org.eclipse.cdt.core.native/.options

@@ -0,0 +1,4 @@
+org.eclipse.cdt.core.native/debug=false
+
+# Used by org.eclipse.cdt.core.win32 fragment
+org.eclipse.cdt.core.native/debug/win32/registry=false

core/org.eclipse.cdt.core.native/build.properties

@@ -20,7 +20,8 @@ bin.includes = plugin.properties,\
                about.mappings,\
                cdt_logo_icon32.png,\
                about.properties,\
-               plugin.xml
+               plugin.xml,\
+               .options
 src.includes = about.html,\
                schema/,\
                native_src/

core/org.eclipse.cdt.core.win32/src/org/eclipse/cdt/internal/core/win32/WindowsRegistryImpl.java

@@ -15,6 +15,7 @@
 
 import org.eclipse.cdt.internal.core.natives.CNativePlugin;
 import org.eclipse.cdt.utils.WindowsRegistry;
+import org.eclipse.core.runtime.Platform;
 
 import com.sun.jna.Native;
 import com.sun.jna.platform.win32.Advapi32;
@@ -33,6 +34,8 @@
  */
 public class WindowsRegistryImpl extends WindowsRegistry {
 
+	private final static boolean DEBUG = Platform.getDebugBoolean(CNativePlugin.PLUGIN_ID + "/debug/win32/registry"); //$NON-NLS-1$
+
 	@Override
 	public String getLocalMachineValue(String subkey, String name) {
 		return getValue(WinReg.HKEY_LOCAL_MACHINE, subkey, name);
@@ -67,7 +70,9 @@ private String getValue(HKEY key, String subkey, String name) {
 		try {
 			return Advapi32Util.registryGetStringValue(key, subkey, name);
 		} catch (Win32Exception e) {
-			CNativePlugin.log(String.format("Unable to get value for %s in %s", name, subkey), e); //$NON-NLS-1$
+			if (DEBUG) {
+				CNativePlugin.log(String.format("Unable to get value for %s in %s", name, subkey), e); //$NON-NLS-1$
+			}
 			return null;
 		}
 	}
@@ -82,7 +87,9 @@ private String getKeyName(HKEY key, String subkey, int index) {
 				Advapi32Util.registryCloseKey(phkKey.getValue());
 			}
 		} catch (Win32Exception e) {
-			CNativePlugin.log(String.format("Unable to get keyname for %s at index %d", subkey, index), e); //$NON-NLS-1$
+			if (DEBUG) {
+				CNativePlugin.log(String.format("Unable to get keyname for %s at index %d", subkey, index), e); //$NON-NLS-1$
+			}
 			return null;
 		}
 	}
@@ -105,7 +112,9 @@ private String getValueName(HKEY key, String subkey, int index) {
 				Advapi32Util.registryCloseKey(phkKey.getValue());
 			}
 		} catch (Win32Exception e) {
-			CNativePlugin.log(String.format("Unable to get valuename for %s at index %d", subkey, index), e); //$NON-NLS-1$
+			if (DEBUG) {
+				CNativePlugin.log(String.format("Unable to get valuename for %s at index %d", subkey, index), e); //$NON-NLS-1$
+			}
 			return null;
 		}
 	}