Fix small bug in StreamBuffer

luprex/core/cpp/luasnap.cpp

@@ -134,6 +134,7 @@ void LuaSnap::snapshot() {
 void LuaSnap::rollback() {
     assert(snapshot_.write_count() != 0);
     deserialize(&snapshot_);
+    assert(snapshot_.at_eof());
     snapshot_.clear();
 }
 

luprex/core/cpp/streambuffer.cpp

@@ -54,6 +54,11 @@ void StreamBuffer::make_space_slow(int64_t bytes) {
     int64_t existing_size = (buf_hi_ - buf_lo_);
     int64_t desired_size = 8192 + ((data_size + bytes) * 2);
 
+    // Update some simple things.
+    pre_read_count_ += (read_cursor_ - buf_lo_);
+    lua_reader_data_ = 0;
+    lua_reader_size_ = 0;
+
     // Move the data to the beginning of the buffer, or to
     // the beginning of a new buffer.
     if (fixed_size_) {
@@ -70,13 +75,8 @@ void StreamBuffer::make_space_slow(int64_t bytes) {
     }
 
     // Update the pointers to the data region.
-    pre_read_count_ += (read_cursor_ - buf_lo_);
     read_cursor_ = buf_lo_;
     write_cursor_ = buf_lo_ + data_size;
-
-    // Flush the lua reader data, if any.
-    lua_reader_data_ = 0;
-    lua_reader_size_ = 0;
 }
 
 char *StreamBuffer::get_overwrite(int64_t size, int64_t write_count_after) {

luprex/core/cpp/streambuffer.hpp

@@ -344,7 +344,7 @@ public:
 
     // Rewind the read cursor to a previous position.
     void unread_to(int64_t read_count);
-
+    
     // Use the stream buffer as a lua_Writer.
     static int lua_writer(lua_State *L, const void* p, size_t sz, void* ud);
     void *lua_writer_ud();