ykxmz/_build/delete_methods.py

# -*- coding: utf-8 -*-
"""删掉指定名字的 Java 方法（按大括号配对，不用正则瞎猜）。

== 为什么不用正则 ==

方法体里可能有字符串、注释、嵌套大括号。正则很难正确跳过这些，
删一半会把文件搞坏。这里做一个**简单但正确**的扫描器：

  * 逐字符走
  * 跳过 `//` 行注释、`/* */` 块注释、`"..."` 字符串、`'c'` 字符字面量
  * 统计 `{` `}` 深度，深度回到 0 就是方法结束
  * 顺便把方法**前面的 javadoc / 注解行**一起删干净（否则留下一堆
    没头没脑的注释）

== 安全措施 ==

  * 名字必须能唯一定位到一个方法定义
  * 删完立刻检查大括号总数是否守恒（删之前总的 `{`/`}` 数减去
    这个方法里的数量，应该等于删之后的）
  * 任何一步不对就抛异常，不写文件
"""
from __future__ import annotations

import re
import sys
from pathlib import Path

JAVA = (Path(__file__).resolve().parent.parent
        / "android" / "src" / "com" / "lanremote" / "watch" / "MainActivity.java")


def find_method_span(text: str, name: str):
    """返回 (start, end) —— 整个方法（含前面的注释/注解）的字符区间。"""
    # 找到定义行
    pat = re.compile(
        r"^[ \t]*(?:@\w+(?:\([^)]*\))?\s*)*"
        r"(?:private|protected|public|static|final|synchronized|\s)*"
        r"(?:[\w<>\[\],.?\s]+?)\s+" + re.escape(name) + r"\s*\([^)]*\)\s*"
        r"(?:throws [\w,.\s]+)?\s*\{",
        re.M)
    matches = list(pat.finditer(text))
    if len(matches) != 1:
        raise SystemExit("✗ %s: 找到 %d 个定义（要恰好 1 个）"
                         % (name, len(matches)))
    m = matches[0]
    def_start = m.start()

    # 往上吃掉紧邻的注释行和注解行
    line_start = text.rfind("\n", 0, def_start) + 1
    start = line_start
    while True:
        prev_end = start - 1
        if prev_end <= 0:
            break
        prev_start = text.rfind("\n", 0, prev_end) + 1
        line = text[prev_start:prev_end].strip()
        if not line:
            break
        if (line.startswith(("*", "//", "/*")) or line.endswith("*/")
                or line.startswith("@")):
            start = prev_start
            continue
        break

    # 从 { 开始找匹配的 }
    i = text.index("{", m.start())
    depth = 0
    n = len(text)
    while i < n:
        ch = text[i]
        # 行注释
        if ch == "/" and i + 1 < n and text[i + 1] == "/":
            i = text.find("\n", i)
            if i < 0:
                raise SystemExit("✗ %s: 行注释没结束" % name)
            continue
        # 块注释
        if ch == "/" and i + 1 < n and text[i + 1] == "*":
            i = text.find("*/", i + 2)
            if i < 0:
                raise SystemExit("✗ %s: 块注释没结束" % name)
            i += 2
            continue
        # 字符串
        if ch == '"':
            i += 1
            while i < n and text[i] != '"':
                if text[i] == "\\":
                    i += 1
                i += 1
            i += 1
            continue
        # 字符字面量
        if ch == "'":
            i += 1
            while i < n and text[i] != "'":
                if text[i] == "\\":
                    i += 1
                i += 1
            i += 1
            continue
        if ch == "{":
            depth += 1
        elif ch == "}":
            depth -= 1
            if depth == 0:
                return start, i + 1
        i += 1
    raise SystemExit("✗ %s: 大括号没配平" % name)


def main() -> int:
    names = sys.argv[1:]
    if not names:
        print("用法: find_orphans.py <方法名> [方法名...]")
        return 1

    text = JAVA.read_text(encoding="utf-8")
    before_open = text.count("{")
    before_close = text.count("}")

    removed_total = 0
    for name in names:
        start, end = find_method_span(text, name)
        chunk = text[start:end]
        removed_total += chunk.count("{")
        # 连同后面的空行一起删
        tail = end
        while tail < len(text) and text[tail] in "\r\n":
            tail += 1
        text = text[:start] + text[tail:]
        print("  ✓ 删除 %-22s %4d 字符" % (name, tail - start))

    # 大括号守恒检查
    if text.count("{") != before_open - removed_total:
        raise SystemExit("✗ 大括号数量不对（删前 %d，删掉 %d，现在 %d）"
                         % (before_open, removed_total, text.count("{")))
    if text.count("{") != text.count("}"):
        raise SystemExit("✗ 大括号不配对：{ %d 个，} %d 个"
                         % (text.count("{"), text.count("}")))

    JAVA.write_text(text, encoding="utf-8", newline="\n")
    print()
    print("  大括号守恒 ✓（{%d / }%d）" % (text.count("{"), text.count("}")))
    return 0


if __name__ == "__main__":
    sys.exit(main())