Cursor.getmulti() initital implementation (jnwatson#201)

lmdb/cpython.c

@@ -2094,6 +2094,112 @@ cursor_first_dup(CursorObject *self)
 static PyObject *
 cursor_value(CursorObject *self);
 
+/**
+ * Cursor.getmulti() -> Array of (key, value)
+ */
+static PyObject *
+cursor_get_multi(CursorObject *self, PyObject *args, PyObject *kwds)
+{
+    struct cursor_get {
+        PyObject *keys;  // TODO Define as PyObject and cast later?
+        int dupdata;
+    } arg = {Py_None, 0};
+
+    PyObject *iter;
+    PyObject *item;
+
+    static const struct argspec argspec[] = {
+        {"keys", ARG_OBJ, OFFSET(cursor_get, keys)},
+        {"dupdata", ARG_BOOL, OFFSET(cursor_get, dupdata)}
+    };
+
+    static PyObject *cache = NULL;
+    if(parse_args(self->valid, SPECSIZE(), argspec, &cache, args, kwds, &arg)) {
+        return NULL;
+    }
+
+    if(! ((iter = PyObject_GetIter(arg.keys)))) {
+        return NULL;
+    }
+
+    PyObject *tup;
+    PyObject *key;
+    PyObject *val;
+    PyObject *ret = PyList_New(0);
+    int as_buffer = self->trans->flags & TRANS_BUFFERS;
+    bool done;
+
+    while((item = PyIter_Next(iter))) {
+        MDB_val mkey;
+
+        if(val_from_buffer(&mkey, item)) {
+            Py_DECREF(item);
+            Py_DECREF(iter);
+            return NULL;
+        } /* val_from_buffer sets exception */
+
+        //TODO validate key?
+
+        done = false;
+        self->key = mkey;
+        if(_cursor_get_c(self, MDB_SET_KEY)) { // MDB_SET?
+            Py_DECREF(item);
+            Py_DECREF(iter);
+            return NULL;
+        }
+
+        while (!done){
+            //TODO valid cursor check?
+
+            if(! self->positioned) {
+                done = true;
+            }
+            // TODO check for mutation and refresh key?
+            else if(_cursor_get_c(self, MDB_GET_CURRENT)) {
+                Py_DECREF(item);
+                Py_DECREF(iter);
+                return NULL;
+            }
+            else{
+                key = obj_from_val(&self->key, as_buffer);
+                PRELOAD_UNLOCKED(0, self->val.mv_data, self->val.mv_size);
+                val = obj_from_val(&self->val, as_buffer);
+                tup = PyTuple_New(2);
+                if (tup && key && val) {
+                    PyTuple_SET_ITEM(tup, 0, key);
+                    PyTuple_SET_ITEM(tup, 1, val);
+                    PyList_Append(ret, tup);
+                    Py_DECREF(tup);
+                }
+                else {
+                    Py_DECREF(key);
+                    Py_DECREF(val);
+                }
+            }
+
+            if(arg.dupdata){
+                if(_cursor_get_c(self, MDB_NEXT_DUP)) {
+                    Py_DECREF(item);
+                    Py_DECREF(iter);
+                    return NULL;
+                }
+            }
+            else {
+                done = true;
+            }
+        }
+        Py_DECREF(item);
+    }
+
+
+    Py_DECREF(iter);
+    if(PyErr_Occurred()) {
+        return NULL;
+    }
+
+    return ret;
+}
+
 /**
  * Cursor.get() -> result
  */
@@ -2829,6 +2935,7 @@ static struct PyMethodDef cursor_methods[] = {
     {"first", (PyCFunction)cursor_first, METH_NOARGS},
     {"first_dup", (PyCFunction)cursor_first_dup, METH_NOARGS},
     {"get", (PyCFunction)cursor_get, METH_VARARGS|METH_KEYWORDS},
+    {"getmulti", (PyCFunction)cursor_get_multi, METH_VARARGS|METH_KEYWORDS},
     {"item", (PyCFunction)cursor_item, METH_NOARGS},
     {"iternext", (PyCFunction)cursor_iternext, METH_VARARGS|METH_KEYWORDS},
     {"iternext_dup", (PyCFunction)cursor_iternext_dup, METH_VARARGS|METH_KEYWORDS},