From c14f38846e6180af139e9a3dfb13575455d6698f Mon Sep 17 00:00:00 2001
From: "valeski%netscape.com"
 <valeski%netscape.com@18797224-902f-48f8-a5cc-f745e15eee43>
Date: Fri, 1 Sep 2000 19:11:24 +0000
Subject: [PATCH] 32185. r=wan-teh. Fixing hashtable enumeration lossage.

git-svn-id: svn://10.0.0.236/trunk@77909 18797224-902f-48f8-a5cc-f745e15eee43
---
 mozilla/xpcom/ds/nsHashtable.cpp | 20 +++++++++++++++-----
 mozilla/xpcom/ds/nsHashtable.h   |  1 +
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/mozilla/xpcom/ds/nsHashtable.cpp b/mozilla/xpcom/ds/nsHashtable.cpp
index 9263eb79d1a..2275b92a86f 100644
--- a/mozilla/xpcom/ds/nsHashtable.cpp
+++ b/mozilla/xpcom/ds/nsHashtable.cpp
@@ -215,7 +215,7 @@ nsHashKey::~nsHashKey(void)
 MOZ_DECL_CTOR_COUNTER(nsHashtable);
 
 nsHashtable::nsHashtable(PRUint32 aInitSize, PRBool threadSafe)
-  : mLock(NULL)
+  : mLock(NULL), mEnumerating(PR_FALSE)
 {
   MOZ_COUNT_CTOR(nsHashtable);
   PRStatus status = PL_HashTableInit(&mHashtable,
@@ -259,7 +259,9 @@ PRBool nsHashtable::Exists(nsHashKey *aKey)
 
   if (mLock) PR_Lock(mLock);
 
-  PLHashEntry **hep = PL_HashTableRawLookup(&mHashtable, hash, (void *) aKey);
+  PLHashEntry *const*hep = mEnumerating ?
+    PL_HashTableRawLookupConst(&mHashtable, hash, (void *) aKey) :
+    PL_HashTableRawLookup(&mHashtable, hash, (void *) aKey);
 
   if (mLock) PR_Unlock(mLock);
 
@@ -273,6 +275,8 @@ void *nsHashtable::Put(nsHashKey *aKey, void *aData) {
 
   if (mLock) PR_Lock(mLock);
 
+  // shouldn't be adding an item during enumeration
+  PR_ASSERT(!mEnumerating);
   PLHashEntry **hep = PL_HashTableRawLookup(&mHashtable, hash, (void *) aKey);
 
   if ((he = *hep) != NULL) {
@@ -297,8 +301,9 @@ void *nsHashtable::Get(nsHashKey *aKey) {
 
   if (mLock) PR_Lock(mLock);
 
-  void *ret = PL_HashTableLookup(&mHashtable, (void *) aKey);
-
+  void *ret = mEnumerating ?
+    PL_HashTableLookupConst(&mHashtable, (void *) aKey) :
+    PL_HashTableLookup(&mHashtable, (void *) aKey);
   if (mLock) PR_Unlock(mLock);
 
   return ret;
@@ -309,7 +314,9 @@ void *nsHashtable::Remove(nsHashKey *aKey) {
   PLHashEntry *he;
 
   if (mLock) PR_Lock(mLock);
-
+  
+  // shouldn't be adding an item during enumeration
+  PR_ASSERT(!mEnumerating);
   PLHashEntry **hep = PL_HashTableRawLookup(&mHashtable, hash, (void *) aKey);
   void *res = NULL;
   
@@ -344,10 +351,13 @@ nsHashtable * nsHashtable::Clone() {
 }
 
 void nsHashtable::Enumerate(nsHashtableEnumFunc aEnumFunc, void* closure) {
+  PRBool wasEnumerating = mEnumerating;
+  mEnumerating = PR_TRUE;
   _HashEnumerateArgs thunk;
   thunk.fn = aEnumFunc;
   thunk.arg = closure;
   PL_HashTableEnumerateEntries(&mHashtable, _hashEnumerate, &thunk);
+  mEnumerating = wasEnumerating;
 }
 
 static PRIntn  PR_CALLBACK _hashEnumerateRemove(PLHashEntry *he, PRIntn i, void *arg)
diff --git a/mozilla/xpcom/ds/nsHashtable.h b/mozilla/xpcom/ds/nsHashtable.h
index 95582931ea1..740666a0e69 100644
--- a/mozilla/xpcom/ds/nsHashtable.h
+++ b/mozilla/xpcom/ds/nsHashtable.h
@@ -79,6 +79,7 @@ protected:
   // members  
   PRLock*               mLock;
   PLHashTable           mHashtable;
+  PRBool                mEnumerating;
 
 public:
   nsHashtable(PRUint32 aSize = 256, PRBool threadSafe = PR_FALSE);