# vector_gdb.py
import gdb # type: ignore
from gdb.printing import PrettyPrinter # type: ignore

class VectorPrinter:
    """兼容新旧注册方式的最终方案"""
    
    def __init__(self, val: gdb.Value):
        self.val:gdb.Value = val
        
    def check_type(self) -> bool:
        """类型检查（兼容匿名结构体）"""
        try:
            if self.val.type.code != gdb.TYPE_CODE_STRUCT:
                return False
            fields = self.val.type.fields()
            if not fields:
                return False
            exp = ['size', 'cap', 'data']
            for t in fields:
                if t.name in exp:
                    exp.remove(t.name)
                else:
                    return False
            return True
        except gdb.error:
            return False
    
    def to_string(self):
        if not self.check_type():
            return "Not a vector"
            
        return "vector({} size={}, cap={})".format(
            self.val.address,
            self.val['size'],
            self.val['cap'],
        )
    
    def display_hint(self):
        return 'array'
    
    def children(self):
        """生成数组元素（关键改进点）"""
        if not self.check_type():
            return []
            
        size = int(self.val['size'])
        cap = int(self.val['cap'])
        data_ptr = self.val['data']
        
        if cap == 0 or data_ptr == 0:
            return []
        
        # 使用 GDB 内置数组转换
        array = data_ptr.dereference()
        array = array.cast(data_ptr.type.target().array(cap - 1))
        
        for i in range(size):
            # state = "<used>" if i < size else "<unused>"
            try:
                value = array[i]
                yield (f"[{i}] {value.type} {value.address}", value)
            except gdb.MemoryError:
                yield (f"[{i}]", "<invalid>")

# 注册方式一：传统append方法（您之前有效的方式）self
def append_printer():
    gdb.pretty_printers.append(
        lambda val: VectorPrinter(val) if VectorPrinter(val).check_type() else None
    )

# 注册方式二：新版注册方法（备用方案）  
def register_new_printer():
    class VectorPrinterLocator(PrettyPrinter):
        def __init__(self):
            super().__init__("vector_printer")
            
        def __call__(self, val):
            ret = VectorPrinter(val).check_type()
            print(f"ret {ret}, type {val.type}, {[(i.name, i.type) for i in  val.type.fields()]}")
            return None
    
    gdb.printing.register_pretty_printer(
        gdb.current_objfile(),
        VectorPrinterLocator()
    )

# 双重注册保证兼容性
append_printer()  # 保留您原来有效的方式
# register_new_printer()  # 添加新版注册

class VectorInfoCommand(gdb.Command):
    """保持原有命令不变"""
    def __init__(self):
        super().__init__("vector_info", gdb.COMMAND_USER)
        
    def invoke(self, argument, from_tty):
        val = gdb.parse_and_eval(argument)
        printer = VectorPrinter(val)
        
        if not printer.check_type():
            print("Invalid vector")
            return
            
        print("=== Vector Details ===")
        print("Size:", val['size'])
        print("Capacity:", val['cap'])
        print("Elements:")
        for name, value in printer.children():
            print(f"  {name}: {value}")

VectorInfoCommand()