add a function to delete all locations

cmdline/cmdline.c

@@ -458,6 +458,7 @@ char* dc_cmdline(dc_context_t* context, const char* cmdline)
 				"chatinfo\n"
 				"sendlocations <seconds>\n"
 				"setlocation <lat> <lng>\n"
+				"dellocations\n"
 				"getlocations\n"
 				"send <text>\n"
 				"sendimage <file> [<text>]\n"
@@ -954,6 +955,10 @@ char* dc_cmdline(dc_context_t* context, const char* cmdline)
 			ret = dc_strdup("ERROR: Latitude or longitude not given.");
 		}
 	}
+	else if (strcmp(cmd, "dellocations")==0) {
+		dc_delete_all_locations(context);
+		ret = COMMAND_SUCCEEDED;
+	}
 	else if (strcmp(cmd, "send")==0)
 	{
 		if (sel_chat) {

src/dc_location.c

@@ -401,6 +401,9 @@ cleanup:
  * The location is sent to all chats where location streaming is enabled
  * using dc_send_locations_to_chat().
  *
+ * Typically results in the event #DC_EVENT_LOCATION_CHANGED with
+ * contact_id set to DC_CONTACT_ID_SELF.
+ *
  * @memberof dc_context_t
  * @param context The context object.
  * @param latitude North-south position of the location.
@@ -530,5 +533,36 @@ dc_array_t* dc_get_locations(dc_context_t* context, uint32_t chat_id, uint32_t
 	}
 
 cleanup:
+	sqlite3_finalize(stmt);
 	return ret;
 }
+
+
+/**
+ * Delete all locations on the current device.
+ * Locations already sent cannot be deleted.
+ *
+ * Typically results in the event #DC_EVENT_LOCATION_CHANGED
+ * with contact_id set to 0.
+ *
+ * @memberof dc_context_t
+ * @param context The context object.
+ * @return None.
+ */
+void dc_delete_all_locations(dc_context_t* context)
+{
+	sqlite3_stmt* stmt = NULL;
+
+	if (context==NULL || context->magic!=DC_CONTEXT_MAGIC) {
+		goto cleanup;
+	}
+
+	stmt = dc_sqlite3_prepare(context->sql,
+		"DELETE FROM locations;");
+	sqlite3_step(stmt);
+
+	context->cb(context, DC_EVENT_LOCATION_CHANGED, 0, 0);
+
+cleanup:
+	sqlite3_finalize(stmt);
+}

src/deltachat.h

@@ -365,6 +365,7 @@ void        dc_send_locations_to_chat       (dc_context_t*, uint32_t chat_id, in
 int         dc_is_sending_locations_to_chat (dc_context_t*, uint32_t chat_id);
 int         dc_set_location                 (dc_context_t*, double latitude, double longitude, double accuracy);
 dc_array_t* dc_get_locations                (dc_context_t*, uint32_t chat_id, uint32_t  contact_id);
+void        dc_delete_all_locations         (dc_context_t*);
 
 
 /**
@@ -1000,6 +1001,8 @@ time_t          dc_lot_get_timestamp     (const dc_lot_t*);
  * Location of one or more contact has changed.
  *
  * @param data1 (int) contact_id of the contact for which the location has changed.
+ *     If the locations of several contacts have been changed,
+ *     eg. after calling dc_delete_all_locations(), this parameter is set to 0.
  * @param data2 0
  * @return 0
  */