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https://github.com/jart/cosmopolitan.git
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0a24b4fc3c
The *NSYNC linked list API is good enough that it deserves to be part of the C libray, so this change writes an improved version of it which uses that offsetof() trick from the Linux Kernel. We vendor all of the *NSYNC tests in third_party which helped confirm the needed refactoring is safe This change also deletes more old code that didn't pan out. My goal here is to work towards a vision where the Cosmopolitan core libraries become less experimental and more focused on curation. This better reflects the current level of quality we've managed to achieve.
99 lines
4.3 KiB
C
99 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8 -*-│
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│vi: set et ft=c ts=8 tw=8 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2016 Google Inc. │
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│ │
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│ Licensed under the Apache License, Version 2.0 (the "License"); │
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│ you may not use this file except in compliance with the License. │
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│ You may obtain a copy of the License at │
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│ │
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│ http://www.apache.org/licenses/LICENSE-2.0 │
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│ │
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│ Unless required by applicable law or agreed to in writing, software │
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│ distributed under the License is distributed on an "AS IS" BASIS, │
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│ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. │
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│ See the License for the specific language governing permissions and │
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│ limitations under the License. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/assert.h"
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#include "libc/errno.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/runtime/syslib.internal.h"
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#include "libc/str/str.h"
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#include "libc/thread/thread.h"
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#include "third_party/nsync/atomic.h"
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#include "third_party/nsync/atomic.internal.h"
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#include "third_party/nsync/futex.internal.h"
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#include "third_party/nsync/mu_semaphore.internal.h"
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#include "third_party/nsync/time.h"
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// clang-format off
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/**
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* @fileoverview Semaphores w/ Apple's Grand Central Dispatch API.
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*/
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#define DISPATCH_TIME_FOREVER ~0ull
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static dispatch_semaphore_t dispatch_semaphore_create(long count) {
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dispatch_semaphore_t ds;
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ds = __syslib->dispatch_semaphore_create (count);
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STRACE ("dispatch_semaphore_create(%ld) → %#lx", count, ds);
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return (ds);
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}
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static long dispatch_semaphore_wait (dispatch_semaphore_t ds,
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dispatch_time_t dt) {
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long rc = __syslib->dispatch_semaphore_wait (ds, dt);
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STRACE ("dispatch_semaphore_wait(%#lx, %ld) → %ld", ds, dt, rc);
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return (rc);
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}
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static long dispatch_semaphore_signal (dispatch_semaphore_t ds) {
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long rc = __syslib->dispatch_semaphore_signal (ds);
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STRACE ("dispatch_semaphore_signal(%#lx) → %ld", ds, rc);
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return (ds);
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}
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static dispatch_time_t dispatch_walltime (const struct timespec *base,
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int64_t offset) {
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return __syslib->dispatch_walltime (base, offset);
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}
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/* Initialize *s; the initial value is 0. */
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void nsync_mu_semaphore_init_gcd (nsync_semaphore *s) {
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*(dispatch_semaphore_t *)s = dispatch_semaphore_create (0);
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}
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/* Wait until the count of *s exceeds 0, and decrement it. */
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errno_t nsync_mu_semaphore_p_gcd (nsync_semaphore *s) {
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dispatch_semaphore_wait (*(dispatch_semaphore_t *)s,
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DISPATCH_TIME_FOREVER);
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return (0);
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}
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/* Wait until one of:
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the count of *s is non-zero, in which case decrement *s and return 0;
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or abs_deadline expires, in which case return ETIMEDOUT. */
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errno_t nsync_mu_semaphore_p_with_deadline_gcd (nsync_semaphore *s,
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nsync_time abs_deadline) {
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errno_t result = 0;
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if (nsync_time_cmp (abs_deadline, nsync_time_no_deadline) == 0) {
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dispatch_semaphore_wait (*(dispatch_semaphore_t *)s,
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DISPATCH_TIME_FOREVER);
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} else {
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struct timespec ts;
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bzero (&ts, sizeof (ts));
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ts.tv_sec = NSYNC_TIME_SEC (abs_deadline);
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ts.tv_nsec = NSYNC_TIME_NSEC (abs_deadline);
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if (dispatch_semaphore_wait (*(dispatch_semaphore_t *)s,
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dispatch_walltime (&abs_deadline, 0)) != 0) {
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result = ETIMEDOUT;
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}
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}
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return (result);
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}
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/* Ensure that the count of *s is at least 1. */
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void nsync_mu_semaphore_v_gcd (nsync_semaphore *s) {
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dispatch_semaphore_signal (*(dispatch_semaphore_t *)s);
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}
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