Correct a mis-cast in the JNI wrapper which just happened to accidentally work. Update JNI binding of sqlite3_context_db_handle() to return the bound-at-open() db instance instead of a new/temp proxy object.

FossilOrigin-Name: 9faca5d9ed4a749421e08bd1da8b7672c0fd31366124fdb613c46e19dece0fc1

ext/jni/src/c/sqlite3-jni.c

@@ -748,18 +748,29 @@ static void PerDbStateJni_dump(PerDbStateJni *s){
    true then a new instance will be allocated if no mapping currently
    exists, else NULL is returned if no mapping is found.
 
-   The 3rd and 4th args should only be non-0 for
-   sqlite3_open(_v2)(). For all other cases, they must be 0, in which
+   The 3rd and 4th args should normally only be non-0 for
+   sqlite3_open(_v2)(). For most other cases, they must be 0, in which
    case the db handle will be fished out of the jDb object and NULL is
    returned if jDb does not have any associated PerDbStateJni.
+
+   If called with a NULL jDb and non-NULL pDb then allocIfNeeded MUST
+   be false and it will look for a matching db object. That usage is
+   required for functions, like sqlite3_context_db_handle(), which
+   return a (sqlite3*).
 */
 FIXME_THREADING
 static PerDbStateJni * PerDbStateJni_for_db(JNIEnv *env, jobject jDb, sqlite3 *pDb, int allocIfNeeded){
   PerDbStateJni * s = S3Global.perDb.aUsed;
-  if(!jDb) return 0;
+  if(!jDb){
+    if(pDb){
+      assert(!allocIfNeeded);
+    }else{
+      return 0;
+    }
+  }
   assert(allocIfNeeded ? !!pDb : 1);
   if(!allocIfNeeded && !pDb){
-    pDb = PtrGet_sqlite3_value(jDb);
+    pDb = PtrGet_sqlite3(jDb);
   }
   for( ; pDb && s; s = s->pNext){
     if(s->pDb == pDb) return s;
@@ -1024,10 +1035,6 @@ static jobject new_sqlite3_context_wrapper(JNIEnv *env, sqlite3_context *sv){
   return new_NativePointerHolder_object(env, "org/sqlite/jni/sqlite3_context", sv);
 }
 
-static jobject new_sqlite3_wrapper(JNIEnv *env, sqlite3 *sv){
-  return new_NativePointerHolder_object(env, "org/sqlite/jni/sqlite3", sv);
-}
-
 enum UDFType {
   UDF_SCALAR = 1,
   UDF_AGGREGATE,
@@ -1670,8 +1677,9 @@ JDECL(jboolean,1compileoption_1used)(JENV_JSELF, jstring name){
 }
 
 JDECL(jobject,1context_1db_1handle)(JENV_JSELF, jobject jpCx){
-  sqlite3 * const db = sqlite3_context_db_handle(PtrGet_sqlite3_context(jpCx));
-  return db ? new_sqlite3_wrapper(env, db) : NULL;
+  sqlite3 * const pDb = sqlite3_context_db_handle(PtrGet_sqlite3_context(jpCx));
+  PerDbStateJni * const ps = pDb ? PerDbStateJni_for_db(env, 0, pDb, 0) : 0;
+  return ps ? ps->jDb : 0;
 }
 
 JDECL(jint,1create_1collation)(JENV_JSELF, jobject jDb,

ext/jni/src/org/sqlite/jni/SQLite3Jni.java

@@ -271,6 +271,10 @@ public final class SQLite3Jni {
   public static native int sqlite3_collation_needed(@NotNull sqlite3 db,
                                                     @Nullable CollationNeeded callback);
 
+  /**
+     Returns the db handle passed to sqlite3_open() or
+     sqlite3_open_v2(), as opposed to a new wrapper object.
+  */
   public static native sqlite3 sqlite3_context_db_handle(@NotNull sqlite3_context cx);
 
   public static native CommitHook sqlite3_commit_hook(@NotNull sqlite3 db, @Nullable CommitHook hook);

ext/jni/src/org/sqlite/jni/Tester1.java

@@ -457,8 +457,7 @@ public class Tester1 {
       // Java...
       new SQLFunction.Scalar(){
         public void xFunc(sqlite3_context cx, sqlite3_value[] args){
-          affirm(db.getNativePointer()
-                   == sqlite3_context_db_handle(cx).getNativePointer());
+          affirm(db == sqlite3_context_db_handle(cx));
           int result = 0;
           for( sqlite3_value v : args ) result += sqlite3_value_int(v);
           xFuncAccum.value += result;// just for post-run testing