diff --git a/mozilla/mailnews/addrbook/src/nsAbDirectoryQuery.cpp b/mozilla/mailnews/addrbook/src/nsAbDirectoryQuery.cpp
index 70b7638eb61..8cd4eb76284 100644
--- a/mozilla/mailnews/addrbook/src/nsAbDirectoryQuery.cpp
+++ b/mozilla/mailnews/addrbook/src/nsAbDirectoryQuery.cpp
@@ -472,7 +472,7 @@ nsresult nsAbDirectoryQuery::matchCard (nsIAbCard* card,
     rv = matchCardExpression (card, expression, &matchFound);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    if (matchFound == PR_TRUE)
+    if (matchFound)
     {
         (*resultLimit)--;
         rv = queryMatch (card, arguments, listener);
@@ -530,14 +530,12 @@ nsresult nsAbDirectoryQuery::matchCardExpression (nsIAbCard* card,
             else
                 return NS_ERROR_FAILURE;
         }
-        if (operation == nsIAbBooleanOperationTypes::OR &&
-            value == PR_TRUE)
+        if (operation == nsIAbBooleanOperationTypes::OR && value)
             break;
-        else if (operation == nsIAbBooleanOperationTypes::AND &&
-            value == PR_FALSE)
+        else if (operation == nsIAbBooleanOperationTypes::AND && !value)
             break;
         else if (operation == nsIAbBooleanOperationTypes::NOT)
-            value = (value == PR_TRUE) ? PR_FALSE : PR_TRUE;
+            value = !value;
     }
     *result = value;
 
diff --git a/mozilla/mailnews/addrbook/src/nsAbDirectoryQueryProxy.cpp b/mozilla/mailnews/addrbook/src/nsAbDirectoryQueryProxy.cpp
index 7211f40915c..f47ef435ce6 100644
--- a/mozilla/mailnews/addrbook/src/nsAbDirectoryQueryProxy.cpp
+++ b/mozilla/mailnews/addrbook/src/nsAbDirectoryQueryProxy.cpp
@@ -53,7 +53,7 @@ nsAbDirectoryQueryProxy::~nsAbDirectoryQueryProxy()
 /* void initiate (in nsIAbDirectory directory); */
 NS_IMETHODIMP nsAbDirectoryQueryProxy::Initiate(nsIAbDirectory *directory)
 {
-    if (mInitiated == PR_TRUE)
+    if (mInitiated)
         return NS_OK;
 
     nsAbDirectoryQuery* _directoryQuery = new nsAbDirectoryQuery (directory);
diff --git a/mozilla/mailnews/addrbook/src/nsAbLDAPDirectoryQuery.cpp b/mozilla/mailnews/addrbook/src/nsAbLDAPDirectoryQuery.cpp
index 8312c122ee6..c2ca97f5c4b 100644
--- a/mozilla/mailnews/addrbook/src/nsAbLDAPDirectoryQuery.cpp
+++ b/mozilla/mailnews/addrbook/src/nsAbLDAPDirectoryQuery.cpp
@@ -148,7 +148,7 @@ nsAbQueryLDAPMessageListener::~nsAbQueryLDAPMessageListener ()
 
 nsresult nsAbQueryLDAPMessageListener::Initiate ()
 {
-    if(mInitialized == PR_TRUE)
+    if (mInitialized)
         return NS_OK;
                 
     mLock = PR_NewLock ();
@@ -171,7 +171,7 @@ nsresult nsAbQueryLDAPMessageListener::Cancel ()
 
     nsAutoLock lock(mLock);
 
-    if (mFinished == PR_TRUE || mCanceled == PR_TRUE)
+    if (mFinished || mCanceled)
         return NS_OK;
 
     mCanceled = PR_TRUE;
@@ -196,12 +196,12 @@ NS_IMETHODIMP nsAbQueryLDAPMessageListener::OnLDAPMessage(nsILDAPMessage *aMessa
     {
         nsAutoLock lock (mLock);
 
-        if (mFinished == PR_TRUE)
+        if (mFinished)
             return NS_OK;
 
         if (messageType == nsILDAPMessage::RES_SEARCH_RESULT)
             mFinished = PR_TRUE;
-        else if (mCanceled == PR_TRUE)
+        else if (mCanceled)
         {
             mFinished = PR_TRUE;
             cancelOperation = PR_TRUE;
@@ -210,7 +210,7 @@ NS_IMETHODIMP nsAbQueryLDAPMessageListener::OnLDAPMessage(nsILDAPMessage *aMessa
     // Leave lock
 
     nsCOMPtr<nsIAbDirectoryQueryResult> queryResult;
-    if (cancelOperation == PR_FALSE)
+    if (!cancelOperation)
     {
         switch (messageType)
         {
@@ -376,7 +376,7 @@ NS_IMETHODIMP nsAbQueryLDAPMessageListener::OnLDAPInit(nsILDAPConnection *aConn,
             NS_ConvertUTF8toUCS2(spec).get(),
             nsIAuthPrompt::SAVE_PASSWORD_PERMANENTLY, getter_Copies(passwd),
             &status);
-        if (NS_FAILED(rv) || status == PR_FALSE) {
+        if (NS_FAILED(rv) || !status) {
             return NS_ERROR_FAILURE;
         }
     }
@@ -405,7 +405,7 @@ NS_IMETHODIMP nsAbQueryLDAPMessageListener::OnLDAPInit(nsILDAPConnection *aConn,
 
 nsresult nsAbQueryLDAPMessageListener::OnLDAPMessageBind (nsILDAPMessage *aMessage)
 {
-    if (mBound == PR_TRUE)
+    if (mBound)
         return NS_OK;
 
     // see whether the bind actually succeeded
@@ -521,7 +521,7 @@ nsresult nsAbQueryLDAPMessageListener::OnLDAPMessageSearchEntry (nsILDAPMessage
                     &hasSetCardProperty);
             NS_ENSURE_SUCCESS(rv, rv);
 
-            if (hasSetCardProperty == PR_FALSE)
+            if (!hasSetCardProperty)
                 continue;
 
             _propertyValue = new nsAbDirectoryQueryPropertyValue(propertyName.get (), card);
@@ -643,7 +643,7 @@ nsAbLDAPDirectoryQuery::~nsAbLDAPDirectoryQuery()
 }
 nsresult nsAbLDAPDirectoryQuery::Initiate ()
 {
-    if(mInitialized == PR_TRUE)
+    if (mInitialized)
         return NS_OK;
 
     mLock = PR_NewLock ();
@@ -673,7 +673,7 @@ NS_IMETHODIMP nsAbLDAPDirectoryQuery::DoQuery(nsIAbDirectoryQueryArguments* argu
     PRBool doSubDirectories;
     rv = arguments->GetQuerySubDirectories (&doSubDirectories);
     NS_ENSURE_SUCCESS(rv, rv);
-    if (doSubDirectories == PR_TRUE)
+    if (doSubDirectories)
         scope = "sub";
     else
         scope = "one";
diff --git a/mozilla/mailnews/addrbook/src/nsAbUtils.cpp b/mozilla/mailnews/addrbook/src/nsAbUtils.cpp
index c818ea69fac..d837c16984c 100644
--- a/mozilla/mailnews/addrbook/src/nsAbUtils.cpp
+++ b/mozilla/mailnews/addrbook/src/nsAbUtils.cpp
@@ -64,7 +64,7 @@ nsresult CStringArrayToCharPtrArray::Convert (nsCStringArray& array,
     for (PRUint32 i = 0; i < size; i++)
     {
 
-        if (copyElements == PR_TRUE)
+        if (copyElements)
             (*returnPropertiesArray)[i] = ToNewCString(*array[i]);
         else
             (*returnPropertiesArray)[i] = NS_CONST_CAST(char*, (*array[i]).get());
@@ -117,7 +117,7 @@ nsresult StringArrayToPRUnicharPtrArray::Convert (nsStringArray& array,
     for (PRUint32 i = 0; i < size; i++)
     {
 
-        if (copyElements == PR_TRUE)
+        if (copyElements)
           (*returnPropertiesArray)[i] = ToNewUnicode(*array[i]);
         else
           (*returnPropertiesArray)[i] = NS_CONST_CAST(PRUnichar*, (*array[i]).get());
diff --git a/mozilla/mailnews/addrbook/src/nsAbUtils.h b/mozilla/mailnews/addrbook/src/nsAbUtils.h
index 8c8d1030525..d17ec0a0f57 100644
--- a/mozilla/mailnews/addrbook/src/nsAbUtils.h
+++ b/mozilla/mailnews/addrbook/src/nsAbUtils.h
@@ -100,7 +100,7 @@ private:
         if (!mArray)
             return;
 
-        if (mFreeElements == PR_TRUE)
+        if (mFreeElements)
             NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(mSize, mArray);
         else
         {
@@ -194,7 +194,7 @@ private:
         if (!mArray)
             return;
 
-        if (mFreeElements == PR_TRUE)
+        if (mFreeElements)
           NS_FREE_XPCOM_ALLOCATED_POINTER_ARRAY(mSize, mArray);
         else
         {
diff --git a/mozilla/mailnews/addrbook/src/nsDirPrefs.cpp b/mozilla/mailnews/addrbook/src/nsDirPrefs.cpp
index fe85a8e79f0..2eaaad6dc4f 100644
--- a/mozilla/mailnews/addrbook/src/nsDirPrefs.cpp
+++ b/mozilla/mailnews/addrbook/src/nsDirPrefs.cpp
@@ -1602,7 +1602,8 @@ static PRBool dir_AreServersSame (DIR_Server *first, DIR_Server *second, PRBool
 		/* assume for right now one personal address book type where offline is PR_FALSE */
 		if ((first->dirType == PABDirectory) && (second->dirType == PABDirectory))
 		{
-			if ((first->isOffline == PR_FALSE) && (second->isOffline == PR_FALSE))  /* are they both really address books? */
+      /* are they both really address books? */
+      if (!first->isOffline && !second->isOffline)
 			{
 				PR_ASSERT(first->fileName && second->fileName);
 				if (first->fileName && second->fileName)
@@ -3245,11 +3246,9 @@ nsresult DIR_GetServerPreferences(nsVoidArray** list)
           /* Don't add servers which are in the old list and don't add a
           * second personal address book.
             */
-            if (   dir_AreServersSame(newServer, oldServer, PR_FALSE)
-              || (   oldServer->dirType == PABDirectory
-              && newServer->dirType == PABDirectory
-              && oldServer->isOffline == PR_FALSE
-              && newServer->isOffline == PR_FALSE))
+            if (dir_AreServersSame(newServer, oldServer, PR_FALSE) ||
+                (oldServer->dirType == PABDirectory && !oldServer->isOffline &&
+                 newServer->dirType == PABDirectory && !newServer->isOffline))
             {
             /* Copy any new prefs out of the new server.
               */