ccls/src/platform_posix.cc

// Copyright 2017-2018 ccls Authors
// SPDX-License-Identifier: Apache-2.0

#if defined(__unix__) || defined(__APPLE__)
#include "platform.h"

#include "utils.h"

#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/types.h> // required for stat.h
#include <sys/wait.h>
#include <unistd.h>
#ifdef __GLIBC__
#include <malloc.h>
#endif

#include <llvm/ADT/SmallString.h>
#include <llvm/Support/Path.h>

#include <string>

std::string NormalizePath(const std::string &path) {
  llvm::SmallString<256> P(path);
  llvm::sys::path::remove_dots(P, true);
  return {P.data(), P.size()};
}

void FreeUnusedMemory() {
#ifdef __GLIBC__
  malloc_trim(4 * 1024 * 1024);
#endif
}

void TraceMe() {
  // If the environment variable is defined, wait for a debugger.
  // In gdb, you need to invoke `signal SIGCONT` if you want ccls to continue
  // after detaching.
  const char *traceme = getenv("CCLS_TRACEME");
  if (traceme)
    raise(traceme[0] == 's' ? SIGSTOP : SIGTSTP);
}

std::string GetExternalCommandOutput(const std::vector<std::string> &command,
                                     std::string_view input) {
  int pin[2], pout[2];
  if (pipe(pin) < 0) {
    perror("pipe(stdin)");
    return "";
  }
  if (pipe(pout) < 0) {
    perror("pipe(stdout)");
    close(pin[0]);
    close(pin[1]);
    return "";
  }
  pid_t child = fork();
  if (child == 0) {
    dup2(pout[0], 0);
    dup2(pin[1], 1);
    close(pin[0]);
    close(pin[1]);
    close(pout[0]);
    close(pout[1]);
    auto argv = new char *[command.size() + 1];
    for (size_t i = 0; i < command.size(); i++)
      argv[i] = const_cast<char *>(command[i].c_str());
    argv[command.size()] = nullptr;
    execvp(argv[0], argv);
    _Exit(127);
  }
  close(pin[1]);
  close(pout[0]);
  // O_NONBLOCK is disabled, write(2) blocks until all bytes are written.
  (void)write(pout[1], input.data(), input.size());
  close(pout[1]);
  std::string ret;
  char buf[4096];
  ssize_t n;
  while ((n = read(pin[0], buf, sizeof buf)) > 0)
    ret.append(buf, n);
  close(pin[0]);
  waitpid(child, NULL, 0);
  return ret;
}

void SpawnThread(void *(*fn)(void *), void *arg) {
  pthread_t thd;
  pthread_attr_t attr;
  struct rlimit rlim;
  size_t stack_size = 4 * 1024 * 1024;
  if (getrlimit(RLIMIT_STACK, &rlim) == 0 &&
      rlim.rlim_cur != RLIM_INFINITY)
    stack_size = rlim.rlim_cur;
  pthread_attr_init(&attr);
  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
  pthread_attr_setstacksize(&attr, stack_size);
  pthread_create(&thd, &attr, fn, arg);
  pthread_attr_destroy(&attr);
}

#endif