squirrel.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "../stdafx.h"
#include "../debug.h"
#include "squirrel_std.hpp"
#include "../fileio_func.h"
#include "../string_func.h"
#include "script_fatalerror.hpp"
#include "../settings_type.h"
#include <sqstdaux.h>
#include <../squirrel/sqpcheader.h>
#include <../squirrel/sqvm.h>
#include "../core/alloc_func.hpp"
 
/*
 * If changing the call paths into the scripting engine, define this symbol to enable full debugging of allocations.
 * This lets you track whether the allocator context is being switched correctly in all call paths.
#define SCRIPT_DEBUG_ALLOCATIONS
 */
 
struct ScriptAllocator {
  size_t allocated_size;   
  size_t allocation_limit; 
 
  bool error_thrown;
 
  static const size_t SAFE_LIMIT = 0x8000000; 
 
#ifdef SCRIPT_DEBUG_ALLOCATIONS
  std::map<void *, size_t> allocations;
#endif
 
  void CheckLimit() const
  {
    if (this->allocated_size > this->allocation_limit) throw Script_FatalError("Maximum memory allocation exceeded");
  }
 
  void CheckAllocation(size_t requested_size, void *p)
  {
    if (this->allocated_size + requested_size > this->allocation_limit && !this->error_thrown) {
      /* Do not allow allocating more than the allocation limit, except when an error is
       * already as then the allocation is for throwing that error in Squirrel, the
       * associated stack trace information and while cleaning up the AI. */
      this->error_thrown = true;
      std::string msg = fmt::format("Maximum memory allocation exceeded by {} bytes when allocating {} bytes",
        this->allocated_size + requested_size - this->allocation_limit, requested_size);
      /* Don't leak the rejected allocation. */
      free(p);
      throw Script_FatalError(msg);
    }
 
    if (p == nullptr) {
      /* The OS did not have enough memory to allocate the object, regardless of the
       * limit imposed by OpenTTD on the amount of memory that may be allocated. */
      if (this->error_thrown) {
        /* The allocation is called in the error handling of a memory allocation
         * failure, then not being able to allocate that small amount of memory
         * means there is no other choice than to bug out completely. */
        MallocError(requested_size);
      }
 
      this->error_thrown = true;
      std::string msg = fmt::format("Out of memory. Cannot allocate {} bytes", requested_size);
      throw Script_FatalError(msg);
    }
  }
 
  void *Malloc(SQUnsignedInteger size)
  {
    void *p = malloc(size);
 
    this->CheckAllocation(size, p);
 
    this->allocated_size += size;
 
#ifdef SCRIPT_DEBUG_ALLOCATIONS
    assert(p != nullptr);
    assert(this->allocations.find(p) == this->allocations.end());
    this->allocations[p] = size;
#endif
 
    return p;
  }
 
  void *Realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size)
  {
    if (p == nullptr) {
      return this->Malloc(size);
    }
    if (size == 0) {
      this->Free(p, oldsize);
      return nullptr;
    }
 
#ifdef SCRIPT_DEBUG_ALLOCATIONS
    assert(this->allocations[p] == oldsize);
    this->allocations.erase(p);
#endif
    /* Can't use realloc directly because memory limit check.
     * If memory exception is thrown, the old pointer is expected
     * to be valid for engine cleanup.
     */
    void *new_p = malloc(size);
 
    this->CheckAllocation(size - oldsize, new_p);
 
    /* Memory limit test passed, we can copy data and free old pointer. */
    memcpy(new_p, p, std::min(oldsize, size));
    free(p);
 
    this->allocated_size -= oldsize;
    this->allocated_size += size;
 
#ifdef SCRIPT_DEBUG_ALLOCATIONS
    assert(new_p != nullptr);
    assert(this->allocations.find(p) == this->allocations.end());
    this->allocations[new_p] = size;
#endif
 
    return new_p;
  }
 
  void Free(void *p, SQUnsignedInteger size)
  {
    if (p == nullptr) return;
    free(p);
    this->allocated_size -= size;
 
#ifdef SCRIPT_DEBUG_ALLOCATIONS
    assert(this->allocations.at(p) == size);
    this->allocations.erase(p);
#endif
  }
 
  ScriptAllocator()
  {
    this->allocated_size = 0;
    this->allocation_limit = static_cast<size_t>(_settings_game.script.script_max_memory_megabytes) << 20;
    if (this->allocation_limit == 0) this->allocation_limit = SAFE_LIMIT; // in case the setting is somehow zero
    this->error_thrown = false;
  }
 
  ~ScriptAllocator()
  {
#ifdef SCRIPT_DEBUG_ALLOCATIONS
    assert(this->allocations.empty());
#endif
  }
};
 
#include "../safeguards.h"
 
ScriptAllocator *_squirrel_allocator = nullptr;
 
/* See 3rdparty/squirrel/squirrel/sqmem.cpp for the default allocator implementation, which this overrides */
#ifndef SQUIRREL_DEFAULT_ALLOCATOR
void *sq_vm_malloc(SQUnsignedInteger size) { return _squirrel_allocator->Malloc(size); }
void *sq_vm_realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size) { return _squirrel_allocator->Realloc(p, oldsize, size); }
void sq_vm_free(void *p, SQUnsignedInteger size) { _squirrel_allocator->Free(p, size); }
#endif
 
size_t Squirrel::GetAllocatedMemory() const noexcept
{
  assert(this->allocator != nullptr);
  return this->allocator->allocated_size;
}
 
 
void Squirrel::CompileError(HSQUIRRELVM vm, const SQChar *desc, const SQChar *source, SQInteger line, SQInteger column)
{
  std::string msg = fmt::format("Error {}:{}/{}: {}", source, line, column, desc);
 
  /* Check if we have a custom print function */
  Squirrel *engine = (Squirrel *)sq_getforeignptr(vm);
  engine->crashed = true;
  SQPrintFunc *func = engine->print_func;
  if (func == nullptr) {
    Debug(misc, 0, "[Squirrel] Compile error: {}", msg);
  } else {
    (*func)(true, msg);
  }
}
 
void Squirrel::ErrorPrintFunc(HSQUIRRELVM vm, const std::string &s)
{
  /* Check if we have a custom print function */
  SQPrintFunc *func = ((Squirrel *)sq_getforeignptr(vm))->print_func;
  if (func == nullptr) {
    fmt::print(stderr, "{}", s);
  } else {
    (*func)(true, s);
  }
}
 
void Squirrel::RunError(HSQUIRRELVM vm, const SQChar *error)
{
  /* Set the print function to something that prints to stderr */
  SQPRINTFUNCTION pf = sq_getprintfunc(vm);
  sq_setprintfunc(vm, &Squirrel::ErrorPrintFunc);
 
  /* Check if we have a custom print function */
  std::string msg = fmt::format("Your script made an error: {}\n", error);
  Squirrel *engine = (Squirrel *)sq_getforeignptr(vm);
  SQPrintFunc *func = engine->print_func;
  if (func == nullptr) {
    fmt::print(stderr, "{}", msg);
  } else {
    (*func)(true, msg);
  }
 
  /* Print below the error the stack, so the users knows what is happening */
  sqstd_printcallstack(vm);
  /* Reset the old print function */
  sq_setprintfunc(vm, pf);
}
 
SQInteger Squirrel::_RunError(HSQUIRRELVM vm)
{
  const SQChar *sErr = nullptr;
 
  if (sq_gettop(vm) >= 1) {
    if (SQ_SUCCEEDED(sq_getstring(vm, -1, &sErr))) {
      Squirrel::RunError(vm, sErr);
      return 0;
    }
  }
 
  Squirrel::RunError(vm, "unknown error");
  return 0;
}
 
void Squirrel::PrintFunc(HSQUIRRELVM vm, const std::string &s)
{
  /* Check if we have a custom print function */
  SQPrintFunc *func = ((Squirrel *)sq_getforeignptr(vm))->print_func;
  if (func == nullptr) {
    fmt::print("{}", s);
  } else {
    (*func)(false, s);
  }
}
 
void Squirrel::AddMethod(const char *method_name, SQFUNCTION proc, uint nparam, const char *params, void *userdata, int size)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushstring(this->vm, method_name, -1);
 
  if (size != 0) {
    void *ptr = sq_newuserdata(vm, size);
    memcpy(ptr, userdata, size);
  }
 
  sq_newclosure(this->vm, proc, size != 0 ? 1 : 0);
  if (nparam != 0) sq_setparamscheck(this->vm, nparam, params);
  sq_setnativeclosurename(this->vm, -1, method_name);
  sq_newslot(this->vm, -3, SQFalse);
}
 
void Squirrel::AddConst(const char *var_name, int value)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushstring(this->vm, var_name, -1);
  sq_pushinteger(this->vm, value);
  sq_newslot(this->vm, -3, SQTrue);
}
 
void Squirrel::AddConst(const char *var_name, bool value)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushstring(this->vm, var_name, -1);
  sq_pushbool(this->vm, value);
  sq_newslot(this->vm, -3, SQTrue);
}
 
void Squirrel::AddClassBegin(const char *class_name)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushroottable(this->vm);
  sq_pushstring(this->vm, class_name, -1);
  sq_newclass(this->vm, SQFalse);
}
 
void Squirrel::AddClassBegin(const char *class_name, const char *parent_class)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushroottable(this->vm);
  sq_pushstring(this->vm, class_name, -1);
  sq_pushstring(this->vm, parent_class, -1);
  if (SQ_FAILED(sq_get(this->vm, -3))) {
    Debug(misc, 0, "[squirrel] Failed to initialize class '{}' based on parent class '{}'", class_name, parent_class);
    Debug(misc, 0, "[squirrel] Make sure that '{}' exists before trying to define '{}'", parent_class, class_name);
    return;
  }
  sq_newclass(this->vm, SQTrue);
}
 
void Squirrel::AddClassEnd()
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_newslot(vm, -3, SQFalse);
  sq_pop(vm, 1);
}
 
bool Squirrel::MethodExists(HSQOBJECT instance, const char *method_name)
{
  assert(!this->crashed);
  ScriptAllocatorScope alloc_scope(this);
 
  int top = sq_gettop(this->vm);
  /* Go to the instance-root */
  sq_pushobject(this->vm, instance);
  /* Find the function-name inside the script */
  sq_pushstring(this->vm, method_name, -1);
  if (SQ_FAILED(sq_get(this->vm, -2))) {
    sq_settop(this->vm, top);
    return false;
  }
  sq_settop(this->vm, top);
  return true;
}
 
bool Squirrel::Resume(int suspend)
{
  assert(!this->crashed);
  ScriptAllocatorScope alloc_scope(this);
 
  /* Did we use more operations than we should have in the
   * previous tick? If so, subtract that from the current run. */
  if (this->overdrawn_ops > 0 && suspend > 0) {
    this->overdrawn_ops -= suspend;
    /* Do we need to wait even more? */
    if (this->overdrawn_ops >= 0) return true;
 
    /* We can now only run whatever is "left". */
    suspend = -this->overdrawn_ops;
  }
 
  this->crashed = !sq_resumecatch(this->vm, suspend);
  this->overdrawn_ops = -this->vm->_ops_till_suspend;
  this->allocator->CheckLimit();
  return this->vm->_suspended != 0;
}
 
void Squirrel::ResumeError()
{
  assert(!this->crashed);
  ScriptAllocatorScope alloc_scope(this);
  sq_resumeerror(this->vm);
}
 
void Squirrel::CollectGarbage()
{
  ScriptAllocatorScope alloc_scope(this);
  sq_collectgarbage(this->vm);
}
 
bool Squirrel::CallMethod(HSQOBJECT instance, const char *method_name, HSQOBJECT *ret, int suspend)
{
  assert(!this->crashed);
  ScriptAllocatorScope alloc_scope(this);
  this->allocator->CheckLimit();
 
  /* Store the stack-location for the return value. We need to
   * restore this after saving or the stack will be corrupted
   * if we're in the middle of a DoCommand. */
  SQInteger last_target = this->vm->_suspended_target;
  /* Store the current top */
  int top = sq_gettop(this->vm);
  /* Go to the instance-root */
  sq_pushobject(this->vm, instance);
  /* Find the function-name inside the script */
  sq_pushstring(this->vm, method_name, -1);
  if (SQ_FAILED(sq_get(this->vm, -2))) {
    Debug(misc, 0, "[squirrel] Could not find '{}' in the class", method_name);
    sq_settop(this->vm, top);
    return false;
  }
  /* Call the method */
  sq_pushobject(this->vm, instance);
  if (SQ_FAILED(sq_call(this->vm, 1, ret == nullptr ? SQFalse : SQTrue, SQTrue, suspend))) return false;
  if (ret != nullptr) sq_getstackobj(vm, -1, ret);
  /* Reset the top, but don't do so for the script main function, as we need
   *  a correct stack when resuming. */
  if (suspend == -1 || !this->IsSuspended()) sq_settop(this->vm, top);
  /* Restore the return-value location. */
  this->vm->_suspended_target = last_target;
 
  return true;
}
 
bool Squirrel::CallStringMethod(HSQOBJECT instance, const char *method_name, std::string *res, int suspend)
{
  HSQOBJECT ret;
  if (!this->CallMethod(instance, method_name, &ret, suspend)) return false;
  if (ret._type != OT_STRING) return false;
  *res = StrMakeValid(ObjectToString(&ret));
  return true;
}
 
bool Squirrel::CallIntegerMethod(HSQOBJECT instance, const char *method_name, int *res, int suspend)
{
  HSQOBJECT ret;
  if (!this->CallMethod(instance, method_name, &ret, suspend)) return false;
  if (ret._type != OT_INTEGER) return false;
  *res = ObjectToInteger(&ret);
  return true;
}
 
bool Squirrel::CallBoolMethod(HSQOBJECT instance, const char *method_name, bool *res, int suspend)
{
  HSQOBJECT ret;
  if (!this->CallMethod(instance, method_name, &ret, suspend)) return false;
  if (ret._type != OT_BOOL) return false;
  *res = ObjectToBool(&ret);
  return true;
}
 
/* static */ bool Squirrel::CreateClassInstanceVM(HSQUIRRELVM vm, const std::string &class_name, void *real_instance, HSQOBJECT *instance, SQRELEASEHOOK release_hook, bool prepend_API_name)
{
  Squirrel *engine = (Squirrel *)sq_getforeignptr(vm);
 
  int oldtop = sq_gettop(vm);
 
  /* First, find the class */
  sq_pushroottable(vm);
 
  if (prepend_API_name) {
    std::string prepended_class_name = engine->GetAPIName();
    prepended_class_name += class_name;
    sq_pushstring(vm, prepended_class_name, -1);
  } else {
    sq_pushstring(vm, class_name, -1);
  }
 
  if (SQ_FAILED(sq_get(vm, -2))) {
    Debug(misc, 0, "[squirrel] Failed to find class by the name '{}{}'", prepend_API_name ? engine->GetAPIName() : "", class_name);
    sq_settop(vm, oldtop);
    return false;
  }
 
  /* Create the instance */
  if (SQ_FAILED(sq_createinstance(vm, -1))) {
    Debug(misc, 0, "[squirrel] Failed to create instance for class '{}{}'", prepend_API_name ? engine->GetAPIName() : "", class_name);
    sq_settop(vm, oldtop);
    return false;
  }
 
  if (instance != nullptr) {
    /* Find our instance */
    sq_getstackobj(vm, -1, instance);
    /* Add a reference to it, so it survives for ever */
    sq_addref(vm, instance);
  }
  sq_remove(vm, -2); // Class-name
  sq_remove(vm, -2); // Root-table
 
  /* Store it in the class */
  sq_setinstanceup(vm, -1, real_instance);
  if (release_hook != nullptr) sq_setreleasehook(vm, -1, release_hook);
 
  if (instance != nullptr) sq_settop(vm, oldtop);
 
  return true;
}
 
bool Squirrel::CreateClassInstance(const std::string &class_name, void *real_instance, HSQOBJECT *instance)
{
  ScriptAllocatorScope alloc_scope(this);
  return Squirrel::CreateClassInstanceVM(this->vm, class_name, real_instance, instance, nullptr);
}
 
Squirrel::Squirrel(const char *APIName) :
  APIName(APIName), allocator(new ScriptAllocator())
{
  this->Initialize();
}
 
void Squirrel::Initialize()
{
  ScriptAllocatorScope alloc_scope(this);
 
  this->global_pointer = nullptr;
  this->print_func = nullptr;
  this->crashed = false;
  this->overdrawn_ops = 0;
  this->vm = sq_open(1024);
 
  /* Handle compile-errors ourself, so we can display it nicely */
  sq_setcompilererrorhandler(this->vm, &Squirrel::CompileError);
  sq_notifyallexceptions(this->vm, _debug_script_level > 5);
  /* Set a good print-function */
  sq_setprintfunc(this->vm, &Squirrel::PrintFunc);
  /* Handle runtime-errors ourself, so we can display it nicely */
  sq_newclosure(this->vm, &Squirrel::_RunError, 0);
  sq_seterrorhandler(this->vm);
 
  /* Set the foreign pointer, so we can always find this instance from within the VM */
  sq_setforeignptr(this->vm, this);
 
  sq_pushroottable(this->vm);
  squirrel_register_global_std(this);
 
  /* Set consts table as delegate of root table, so consts/enums defined via require() are accessible */
  sq_pushconsttable(this->vm);
  sq_setdelegate(this->vm, -2);
}
 
class SQFile {
private:
  FileHandle file;
  size_t size;
  size_t pos;
 
public:
  SQFile(FileHandle file, size_t size) : file(std::move(file)), size(size), pos(0) {}
 
  size_t Read(void *buf, size_t elemsize, size_t count)
  {
    assert(elemsize != 0);
    if (this->pos + (elemsize * count) > this->size) {
      count = (this->size - this->pos) / elemsize;
    }
    if (count == 0) return 0;
    size_t ret = fread(buf, elemsize, count, this->file);
    this->pos += ret * elemsize;
    return ret;
  }
};
 
static char32_t _io_file_lexfeed_ASCII(SQUserPointer file)
{
  unsigned char c;
  if (((SQFile *)file)->Read(&c, sizeof(c), 1) > 0) return c;
  return 0;
}
 
static char32_t _io_file_lexfeed_UTF8(SQUserPointer file)
{
  char buffer[5];
 
  /* Read the first character, and get the length based on UTF-8 specs. If invalid, bail out. */
  if (((SQFile *)file)->Read(buffer, sizeof(buffer[0]), 1) != 1) return 0;
  uint len = Utf8EncodedCharLen(buffer[0]);
  if (len == 0) return -1;
 
  /* Read the remaining bits. */
  if (len > 1 && ((SQFile *)file)->Read(buffer + 1, sizeof(buffer[0]), len - 1) != len - 1) return 0;
 
  /* Convert the character, and when definitely invalid, bail out as well. */
  char32_t c;
  if (Utf8Decode(&c, buffer) != len) return -1;
 
  return c;
}
 
static char32_t _io_file_lexfeed_UCS2_no_swap(SQUserPointer file)
{
  unsigned short c;
  if (((SQFile *)file)->Read(&c, sizeof(c), 1) > 0) return (char32_t)c;
  return 0;
}
 
static char32_t _io_file_lexfeed_UCS2_swap(SQUserPointer file)
{
  unsigned short c;
  if (((SQFile *)file)->Read(&c, sizeof(c), 1) > 0) {
    c = ((c >> 8) & 0x00FF)| ((c << 8) & 0xFF00);
    return (char32_t)c;
  }
  return 0;
}
 
static SQInteger _io_file_read(SQUserPointer file, SQUserPointer buf, SQInteger size)
{
  SQInteger ret = ((SQFile *)file)->Read(buf, 1, size);
  if (ret == 0) return -1;
  return ret;
}
 
SQRESULT Squirrel::LoadFile(HSQUIRRELVM vm, const std::string &filename, SQBool printerror)
{
  ScriptAllocatorScope alloc_scope(this);
 
  std::optional<FileHandle> file = std::nullopt;
  size_t size;
  if (strncmp(this->GetAPIName(), "AI", 2) == 0) {
    file = FioFOpenFile(filename, "rb", AI_DIR, &size);
    if (!file.has_value()) file = FioFOpenFile(filename, "rb", AI_LIBRARY_DIR, &size);
  } else if (strncmp(this->GetAPIName(), "GS", 2) == 0) {
    file = FioFOpenFile(filename, "rb", GAME_DIR, &size);
    if (!file.has_value()) file = FioFOpenFile(filename, "rb", GAME_LIBRARY_DIR, &size);
  } else {
    NOT_REACHED();
  }
 
  if (!file.has_value()) {
    return sq_throwerror(vm, "cannot open the file");
  }
  unsigned short bom = 0;
  if (size >= 2) {
    if (fread(&bom, 1, sizeof(bom), *file) != sizeof(bom)) return sq_throwerror(vm, "cannot read the file");;
  }
 
  SQLEXREADFUNC func;
  switch (bom) {
    case SQ_BYTECODE_STREAM_TAG: { // BYTECODE
      if (fseek(*file, -2, SEEK_CUR) < 0) {
        return sq_throwerror(vm, "cannot seek the file");
      }
 
      SQFile f(std::move(*file), size);
      if (SQ_SUCCEEDED(sq_readclosure(vm, _io_file_read, &f))) {
        return SQ_OK;
      }
      return sq_throwerror(vm, "Couldn't read bytecode");
    }
    case 0xFFFE:
      /* Either this file is encoded as big-endian and we're on a little-endian
       * machine, or this file is encoded as little-endian and we're on a big-endian
       * machine. Either way, swap the bytes of every word we read. */
      func = _io_file_lexfeed_UCS2_swap;
      size -= 2; // Skip BOM
      break;
    case 0xFEFF:
      func = _io_file_lexfeed_UCS2_no_swap;
      size -= 2; // Skip BOM
      break;
    case 0xBBEF:   // UTF-8
    case 0xEFBB: { // UTF-8 on big-endian machine
      /* Similarly, check the file is actually big enough to finish checking BOM */
      if (size < 3) {
        return sq_throwerror(vm, "I/O error");
      }
      unsigned char uc;
      if (fread(&uc, 1, sizeof(uc), *file) != sizeof(uc) || uc != 0xBF) {
        return sq_throwerror(vm, "Unrecognized encoding");
      }
      func = _io_file_lexfeed_UTF8;
      size -= 3; // Skip BOM
      break;
    }
    default: // ASCII
      func = _io_file_lexfeed_ASCII;
      /* Account for when we might not have fread'd earlier */
      if (size >= 2 && fseek(*file, -2, SEEK_CUR) < 0) {
        return sq_throwerror(vm, "cannot seek the file");
      }
      break;
  }
 
  SQFile f(std::move(*file), size);
  if (SQ_SUCCEEDED(sq_compile(vm, func, &f, filename.c_str(), printerror))) {
    return SQ_OK;
  }
  return SQ_ERROR;
}
 
bool Squirrel::LoadScript(HSQUIRRELVM vm, const std::string &script, bool in_root)
{
  ScriptAllocatorScope alloc_scope(this);
 
  /* Make sure we are always in the root-table */
  if (in_root) sq_pushroottable(vm);
 
  SQInteger ops_left = vm->_ops_till_suspend;
  /* Load and run the script */
  if (SQ_SUCCEEDED(LoadFile(vm, script, SQTrue))) {
    sq_push(vm, -2);
    if (SQ_SUCCEEDED(sq_call(vm, 1, SQFalse, SQTrue, 100000))) {
      sq_pop(vm, 1);
      /* After compiling the file we want to reset the amount of opcodes. */
      vm->_ops_till_suspend = ops_left;
      return true;
    }
  }
 
  vm->_ops_till_suspend = ops_left;
  Debug(misc, 0, "[squirrel] Failed to compile '{}'", script);
  return false;
}
 
bool Squirrel::LoadScript(const std::string &script)
{
  return LoadScript(this->vm, script);
}
 
Squirrel::~Squirrel()
{
  this->Uninitialize();
}
 
void Squirrel::Uninitialize()
{
  ScriptAllocatorScope alloc_scope(this);
 
  /* Remove the delegation */
  sq_pushroottable(this->vm);
  sq_pushnull(this->vm);
  sq_setdelegate(this->vm, -2);
  sq_pop(this->vm, 1);
 
  /* Clean up the stuff */
  sq_pop(this->vm, 1);
  sq_close(this->vm);
 
  assert(this->allocator->allocated_size == 0);
 
  /* Reset memory allocation errors. */
  this->allocator->error_thrown = false;
}
 
void Squirrel::Reset()
{
  this->Uninitialize();
  this->Initialize();
}
 
void Squirrel::InsertResult(bool result)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushbool(this->vm, result);
  if (this->IsSuspended()) { // Called before resuming a suspended script?
    vm->GetAt(vm->_stackbase + vm->_suspended_target) = vm->GetUp(-1);
    vm->Pop();
  }
}
 
void Squirrel::InsertResult(int result)
{
  ScriptAllocatorScope alloc_scope(this);
 
  sq_pushinteger(this->vm, result);
  if (this->IsSuspended()) { // Called before resuming a suspended script?
    vm->GetAt(vm->_stackbase + vm->_suspended_target) = vm->GetUp(-1);
    vm->Pop();
  }
}
 
/* static */ void Squirrel::DecreaseOps(HSQUIRRELVM vm, int ops)
{
  vm->DecreaseOps(ops);
}
 
bool Squirrel::IsSuspended()
{
  return this->vm->_suspended != 0;
}
 
bool Squirrel::HasScriptCrashed()
{
  return this->crashed;
}
 
void Squirrel::CrashOccurred()
{
  this->crashed = true;
}
 
bool Squirrel::CanSuspend()
{
  ScriptAllocatorScope alloc_scope(this);
  return sq_can_suspend(this->vm);
}
 
SQInteger Squirrel::GetOpsTillSuspend()
{
  return this->vm->_ops_till_suspend;
}