#!/usr/bin/env python3
"""Run a test repeatedly with mallocfail.

Usage: run_mallocfail [--ctest=<cost>] [<exe>...]

This runs the programs with mallocfail until there are no more additional
stack hashes for mallocfail to try out.

Passing "--ctest" additionally runs all the tests with a cost lower than the
given flag value. Cost is measured in seconds of runtime.

You need to build mallocfail (https://github.com/ralight/mallocfail) and install
it to /usr/local/lib/mallocfail. Change _MALLOCFAIL_SO below if you want it
elsewhere.
"""
import glob
import multiprocessing
import os
import shutil
import subprocess
import sys
import tempfile
import time
from typing import Dict
from typing import List
from typing import NoReturn
from typing import Optional
from typing import Tuple

_PRIMER = "./unit_util_test"
_MALLOCFAIL_SO = "/usr/local/lib/mallocfail.so"
_HASHES = "mallocfail_hashes"
_HASHES_PREV = "mallocfail_hashes.prev"
_TIMEOUT = 3.0

_ENV = {
    "LD_PRELOAD": _MALLOCFAIL_SO,
    "UBSAN_OPTIONS": "color=always,print_stacktrace=1,exitcode=11",
}


def run_mallocfail(tmpdir: str, timeout: float, exe: str,
                   iteration: int) -> bool:
    """Run a program with mallocfail."""
    print(f"\x1b[1;33mmallocfail '{exe}' run #{iteration}\x1b[0m")
    hashes = os.path.join(tmpdir, _HASHES)
    hashes_prev = os.path.join(tmpdir, _HASHES_PREV)
    if os.path.exists(hashes):
        shutil.copy(hashes, hashes_prev)
    try:
        proc = subprocess.run([exe], timeout=timeout, env=_ENV, cwd=tmpdir)
    except subprocess.TimeoutExpired:
        print(f"\x1b[1;34mProgram {exe} timed out\x1b[0m")
        return True
    finally:
        assert os.path.exists(hashes)
        if os.path.exists(hashes_prev):
            with open(hashes_prev, "r") as prev:
                with open(hashes, "r") as cur:
                    if prev.read() == cur.read():
                        # Done: no new stack hashes.
                        return False

    if proc.returncode in (0, 1):
        # Process exited cleanly (success or failure).
        pass
    elif proc.returncode == -6:
        # Assertion failed.
        pass
    elif proc.returncode == -14:
        print(f"\x1b[0;34mProgram '{exe}' timed out\x1b[0m")
    else:
        print(
            f"\x1b[1;34mProgram '{exe}' failed to handle OOM situation cleanly\x1b[0m"
        )
        raise Exception("Aborting test")

    return True


def ctest_costs() -> Dict[str, float]:
    with open("Testing/Temporary/CTestCostData.txt", "r") as fh:
        costs = {}
        for line in fh.readlines():
            if line.startswith("---"):
                break
            prog, _, cost = line.rstrip().split(" ")
            costs[prog] = float(cost)
        return costs


def find_prog(name: str) -> Tuple[Optional[str], ...]:
    def attempt(path: str) -> Optional[str]:
        if os.path.exists(path):
            return path
        return None

    return (attempt(f"./unit_{name}_test"), attempt(f"./auto_{name}_test"))


def parse_flags(args: List[str]) -> Tuple[Dict[str, str], List[str]]:
    flags: Dict[str, str] = {}
    exes: List[str] = []
    for arg in args:
        if arg.startswith("--"):
            flag, value = arg.split("=", 1)
            flags[flag] = value
        else:
            exes.append(arg)
    return flags, exes


def loop_mallocfail(tmpdir: str, timeout: float, exe: str) -> None:
    i = 1
    while run_mallocfail(tmpdir, timeout, exe, i):
        i += 1


def isolated_mallocfail(timeout: int, exe: str) -> None:
    with tempfile.TemporaryDirectory(prefix="mallocfail") as tmpdir:
        print(f"\x1b[1;33mRunning for {exe} in isolated path {tmpdir}\x1b[0m")
        shutil.copy(exe, os.path.join(tmpdir, exe))
        shutil.copy(_HASHES, os.path.join(tmpdir, _HASHES))
        loop_mallocfail(tmpdir, timeout, exe)


def main(args: List[str]) -> None:
    """Run a program repeatedly under mallocfail."""
    if len(args) == 1:
        print(f"Usage: {args[0]} <exe>")
        sys.exit(1)

    flags, exes = parse_flags(args[1:])

    timeout = _TIMEOUT
    if "--ctest" in flags:
        costs = ctest_costs()
        max_cost = float(flags["--ctest"])
        timeout = max(max_cost + 1, timeout)
        exes.extend(prog for test in costs.keys() for prog in find_prog(test)
                    if costs[test] <= max_cost and prog)
    if "--jobs" in flags:
        jobs = int(flags["--jobs"])
    else:
        jobs = 1

    # Start by running util_test, which allocates no memory of its own, just
    # to prime the mallocfail hashes so it doesn't make global initialisers
    # such as llvm_gcov_init fail.
    if os.path.exists(_PRIMER):
        print(f"\x1b[1;33mPriming hashes with unit_util_test\x1b[0m")
        loop_mallocfail(".", timeout, _PRIMER)

    print(f"\x1b[1;33m--------------------------------\x1b[0m")
    print(f"\x1b[1;33mStarting mallocfail for {len(exes)} programs:\x1b[0m")
    print(f"\x1b[1;33m{exes}\x1b[0m")
    print(f"\x1b[1;33m--------------------------------\x1b[0m")
    time.sleep(1)
    with multiprocessing.Pool(jobs) as p:
        done = tuple(
            p.starmap(isolated_mallocfail, ((timeout, exe) for exe in exes)))
        print(f"\x1b[1;32mCompleted {len(done)} programs\x1b[0m")


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