// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

#include "vm/globals.h"
#if defined(HOST_OS_FUCHSIA)

#include "vm/os.h"

#include <errno.h>
#include <zircon/process.h>
#include <zircon/syscalls.h>
#include <zircon/syscalls/object.h>
#include <zircon/types.h>

#include "platform/assert.h"
#include "vm/zone.h"

namespace dart {

#ifndef PRODUCT

DEFINE_FLAG(bool,
            generate_perf_events_symbols,
            false,
            "Generate events symbols for profiling with perf");

#endif  // !PRODUCT

const char* OS::Name() {
  return "fuchsia";
}

intptr_t OS::ProcessId() {
  return static_cast<intptr_t>(getpid());
}

static bool LocalTime(int64_t seconds_since_epoch, tm* tm_result) {
  time_t seconds = static_cast<time_t>(seconds_since_epoch);
  if (seconds != seconds_since_epoch) {
    return false;
  }
  struct tm* error_code = localtime_r(&seconds, tm_result);
  return error_code != NULL;
}

const char* OS::GetTimeZoneName(int64_t seconds_since_epoch) {
  tm decomposed;
  bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
  // If unsuccessful, return an empty string like V8 does.
  return (succeeded && (decomposed.tm_zone != NULL)) ? decomposed.tm_zone : "";
}

int OS::GetTimeZoneOffsetInSeconds(int64_t seconds_since_epoch) {
  tm decomposed;
  bool succeeded = LocalTime(seconds_since_epoch, &decomposed);
  // Even if the offset was 24 hours it would still easily fit into 32 bits.
  // If unsuccessful, return zero like V8 does.
  return succeeded ? static_cast<int>(decomposed.tm_gmtoff) : 0;
}

int OS::GetLocalTimeZoneAdjustmentInSeconds() {
  // TODO(floitsch): avoid excessive calls to tzset?
  tzset();
  // Even if the offset was 24 hours it would still easily fit into 32 bits.
  // Note that Unix and Dart disagree on the sign.
  return static_cast<int>(-timezone);
}

int64_t OS::GetCurrentTimeMillis() {
  return GetCurrentTimeMicros() / 1000;
}

int64_t OS::GetCurrentTimeMicros() {
  return zx_time_get(ZX_CLOCK_UTC) / kNanosecondsPerMicrosecond;
}

int64_t OS::GetCurrentMonotonicTicks() {
  return zx_time_get(ZX_CLOCK_MONOTONIC);
}

int64_t OS::GetCurrentMonotonicFrequency() {
  return kNanosecondsPerSecond;
}

int64_t OS::GetCurrentMonotonicMicros() {
  int64_t ticks = GetCurrentMonotonicTicks();
  ASSERT(GetCurrentMonotonicFrequency() == kNanosecondsPerSecond);
  return ticks / kNanosecondsPerMicrosecond;
}

int64_t OS::GetCurrentThreadCPUMicros() {
  return zx_time_get(ZX_CLOCK_THREAD) / kNanosecondsPerMicrosecond;
}

// TODO(5411554):  May need to hoist these architecture dependent code
// into a architecture specific file e.g: os_ia32_fuchsia.cc
intptr_t OS::ActivationFrameAlignment() {
#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64) ||                   \
    defined(TARGET_ARCH_ARM64)
  const int kMinimumAlignment = 16;
#elif defined(TARGET_ARCH_ARM) || defined(TARGET_ARCH_DBC)
  const int kMinimumAlignment = 8;
#else
#error Unsupported architecture.
#endif
  intptr_t alignment = kMinimumAlignment;
  // TODO(5411554): Allow overriding default stack alignment for
  // testing purposes.
  // Flags::DebugIsInt("stackalign", &alignment);
  ASSERT(Utils::IsPowerOfTwo(alignment));
  ASSERT(alignment >= kMinimumAlignment);
  return alignment;
}

intptr_t OS::PreferredCodeAlignment() {
#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64) ||                   \
    defined(TARGET_ARCH_ARM64) || defined(TARGET_ARCH_DBC)
  const int kMinimumAlignment = 32;
#elif defined(TARGET_ARCH_ARM)
  const int kMinimumAlignment = 16;
#else
#error Unsupported architecture.
#endif
  intptr_t alignment = kMinimumAlignment;
  // TODO(5411554): Allow overriding default code alignment for
  // testing purposes.
  // Flags::DebugIsInt("codealign", &alignment);
  ASSERT(Utils::IsPowerOfTwo(alignment));
  ASSERT(alignment >= kMinimumAlignment);
  ASSERT(alignment <= OS::kMaxPreferredCodeAlignment);
  return alignment;
}

int OS::NumberOfAvailableProcessors() {
  return sysconf(_SC_NPROCESSORS_CONF);
}

void OS::Sleep(int64_t millis) {
  SleepMicros(millis * kMicrosecondsPerMillisecond);
}

void OS::SleepMicros(int64_t micros) {
  zx_nanosleep(zx_deadline_after(micros * kNanosecondsPerMicrosecond));
}

void OS::DebugBreak() {
  UNIMPLEMENTED();
}

uintptr_t DART_NOINLINE OS::GetProgramCounter() {
  return reinterpret_cast<uintptr_t>(
      __builtin_extract_return_addr(__builtin_return_address(0)));
}

char* OS::StrNDup(const char* s, intptr_t n) {
  return strndup(s, n);
}

intptr_t OS::StrNLen(const char* s, intptr_t n) {
  return strnlen(s, n);
}

void OS::Print(const char* format, ...) {
  va_list args;
  va_start(args, format);
  VFPrint(stdout, format, args);
  va_end(args);
}

void OS::VFPrint(FILE* stream, const char* format, va_list args) {
  vfprintf(stream, format, args);
  fflush(stream);
}

int OS::SNPrint(char* str, size_t size, const char* format, ...) {
  va_list args;
  va_start(args, format);
  int retval = VSNPrint(str, size, format, args);
  va_end(args);
  return retval;
}

int OS::VSNPrint(char* str, size_t size, const char* format, va_list args) {
  int retval = vsnprintf(str, size, format, args);
  if (retval < 0) {
    FATAL1("Fatal error in OS::VSNPrint with format '%s'", format);
  }
  return retval;
}

char* OS::SCreate(Zone* zone, const char* format, ...) {
  va_list args;
  va_start(args, format);
  char* buffer = VSCreate(zone, format, args);
  va_end(args);
  return buffer;
}

char* OS::VSCreate(Zone* zone, const char* format, va_list args) {
  // Measure.
  va_list measure_args;
  va_copy(measure_args, args);
  intptr_t len = VSNPrint(NULL, 0, format, measure_args);
  va_end(measure_args);

  char* buffer;
  if (zone) {
    buffer = zone->Alloc<char>(len + 1);
  } else {
    buffer = reinterpret_cast<char*>(malloc(len + 1));
  }
  ASSERT(buffer != NULL);

  // Print.
  va_list print_args;
  va_copy(print_args, args);
  VSNPrint(buffer, len + 1, format, print_args);
  va_end(print_args);
  return buffer;
}

bool OS::StringToInt64(const char* str, int64_t* value) {
  ASSERT(str != NULL && strlen(str) > 0 && value != NULL);
  int32_t base = 10;
  char* endptr;
  int i = 0;
  if (str[0] == '-') {
    i = 1;
  }
  if ((str[i] == '0') && (str[i + 1] == 'x' || str[i + 1] == 'X') &&
      (str[i + 2] != '\0')) {
    base = 16;
  }
  errno = 0;
  *value = strtoll(str, &endptr, base);
  return ((errno == 0) && (endptr != str) && (*endptr == 0));
}

void OS::RegisterCodeObservers() {
#ifndef PRODUCT
  if (FLAG_generate_perf_events_symbols) {
    UNIMPLEMENTED();
  }
#endif  // !PRODUCT
}

void OS::PrintErr(const char* format, ...) {
  va_list args;
  va_start(args, format);
  VFPrint(stderr, format, args);
  va_end(args);
}

void OS::InitOnce() {
  // TODO(5411554): For now we check that initonce is called only once,
  // Once there is more formal mechanism to call InitOnce we can move
  // this check there.
  static bool init_once_called = false;
  ASSERT(init_once_called == false);
  init_once_called = true;
}

void OS::Shutdown() {}

void OS::Abort() {
  abort();
}

void OS::Exit(int code) {
  UNIMPLEMENTED();
}

}  // namespace dart

#endif  // defined(HOST_OS_FUCHSIA)