text: // Copyright 2006-2008 the V8 project authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #include <cctype>
  #include <cstdlib>
  #include <sstream>
  
  #include "src/v8.h"
  
  #include "src/assembler.h"
  #include "src/base/functional.h"
  #include "src/base/platform/platform.h"
  #include "src/ostreams.h"
  
  namespace v8 {
  namespace internal {
  
  // Define all of our flags.
  #define FLAG_MODE_DEFINE
  #include "src/flag-definitions.h"  // NOLINT
  
  // Define all of our flags default values.
  #define FLAG_MODE_DEFINE_DEFAULTS
  #include "src/flag-definitions.h"  // NOLINT
  
  namespace {
  
  // This structure represents a single entry in the flag system, with a pointer
  // to the actual flag, default value, comment, etc.  This is designed to be POD
  // initialized as to avoid requiring static constructors.
  struct Flag {
    enum FlagType { TYPE_BOOL, TYPE_MAYBE_BOOL, TYPE_INT, TYPE_FLOAT,
                    TYPE_STRING, TYPE_ARGS };
  
    FlagType type_;           // What type of flag, bool, int, or string.
    const char* name_;        // Name of the flag, ex "my_flag".
    void* valptr_;            // Pointer to the global flag variable.
    const void* defptr_;      // Pointer to the default value.
    const char* cmt_;         // A comment about the flags purpose.
    bool owns_ptr_;           // Does the flag own its string value?
  
    FlagType type() const { return type_; }
  
    const char* name() const { return name_; }
  
    const char* comment() const { return cmt_; }
  
    bool* bool_variable() const {
      DCHECK(type_ == TYPE_BOOL);
      return reinterpret_cast<bool*>(valptr_);
    }
  
    MaybeBoolFlag* maybe_bool_variable() const {
      DCHECK(type_ == TYPE_MAYBE_BOOL);
      return reinterpret_cast<MaybeBoolFlag*>(valptr_);
    }
  
    int* int_variable() const {
      DCHECK(type_ == TYPE_INT);
      return reinterpret_cast<int*>(valptr_);
    }
  
    double* float_variable() const {
      DCHECK(type_ == TYPE_FLOAT);
      return reinterpret_cast<double*>(valptr_);
    }
  
    const char* string_value() const {
      DCHECK(type_ == TYPE_STRING);
      return *reinterpret_cast<const char**>(valptr_);
    }
  
    void set_string_value(const char* value, bool owns_ptr) {
      DCHECK(type_ == TYPE_STRING);
      const char** ptr = reinterpret_cast<const char**>(valptr_);
      if (owns_ptr_ && *ptr != NULL) DeleteArray(*ptr);
      *ptr = value;
      owns_ptr_ = owns_ptr;
    }
  
    JSArguments* args_variable() const {
      DCHECK(type_ == TYPE_ARGS);
      return reinterpret_cast<JSArguments*>(valptr_);
    }
  
    bool bool_default() const {
      DCHECK(type_ == TYPE_BOOL);
      return *reinterpret_cast<const bool*>(defptr_);
    }
  
    int int_default() const {
      DCHECK(type_ == TYPE_INT);
      return *reinterpret_cast<const int*>(defptr_);
    }
  
    double float_default() const {
      DCHECK(type_ == TYPE_FLOAT);
      return *reinterpret_cast<const double*>(defptr_);
    }
  
    const char* string_default() const {
      DCHECK(type_ == TYPE_STRING);
      return *reinterpret_cast<const char* const *>(defptr_);
    }
  
    JSArguments args_default() const {
      DCHECK(type_ == TYPE_ARGS);
      return *reinterpret_cast<const JSArguments*>(defptr_);
    }
  
    // Compare this flag's current value against the default.
    bool IsDefault() const {
      switch (type_) {
        case TYPE_BOOL:
          return *bool_variable() == bool_default();
        case TYPE_MAYBE_BOOL:
          return maybe_bool_variable()->has_value == false;
        case TYPE_INT:
          return *int_variable() == int_default();
        case TYPE_FLOAT:
          return *float_variable() == float_default();
        case TYPE_STRING: {
          const char* str1 = string_value();
          const char* str2 = string_default();
          if (str2 == NULL) return str1 == NULL;
          if (str1 == NULL) return str2 == NULL;
          return strcmp(str1, str2) == 0;
        }
        case TYPE_ARGS:
          return args_variable()->argc == 0;
      }
      UNREACHABLE();
      return true;
    }
  
    // Set a flag back to it's default value.
    void Reset() {
      switch (type_) {
        case TYPE_BOOL:
          *bool_variable() = bool_default();
          break;
        case TYPE_MAYBE_BOOL:
          *maybe_bool_variable() = MaybeBoolFlag::Create(false, false);
          break;
        case TYPE_INT:
          *int_variable() = int_default();
          break;
        case TYPE_FLOAT:
          *float_variable() = float_default();
          break;
        case TYPE_STRING:
          set_string_value(string_default(), false);
          break;
        case TYPE_ARGS:
          *args_variable() = args_default();
          break;
      }
    }
  };
  
  Flag flags[] = {
  #define FLAG_MODE_META
  #include "src/flag-definitions.h"
  };
  
  const size_t num_flags = sizeof(flags) / sizeof(*flags);
  
  }  // namespace
  
  
  static const char* Type2String(Flag::FlagType type) {
    switch (type) {
      case Flag::TYPE_BOOL: return "bool";
      case Flag::TYPE_MAYBE_BOOL: return "maybe_bool";
      case Flag::TYPE_INT: return "int";
      case Flag::TYPE_FLOAT: return "float";
      case Flag::TYPE_STRING: return "string";
      case Flag::TYPE_ARGS: return "arguments";
    }
    UNREACHABLE();
    return NULL;
  }
  
  
  std::ostream& operator<<(std::ostream& os, const Flag& flag) {  // NOLINT
    switch (flag.type()) {
      case Flag::TYPE_BOOL:
        os << (*flag.bool_variable() ? "true" : "false");
        break;
      case Flag::TYPE_MAYBE_BOOL:
        os << (flag.maybe_bool_variable()->has_value
                   ? (flag.maybe_bool_variable()->value ? "true" : "false")
                   : "unset");
        break;
      case Flag::TYPE_INT:
        os << *flag.int_variable();
        break;
      case Flag::TYPE_FLOAT:
        os << *flag.float_variable();
        break;
      case Flag::TYPE_STRING: {
        const char* str = flag.string_value();
        os << (str ? str : "NULL");
        break;
      }
      case Flag::TYPE_ARGS: {
        JSArguments args = *flag.args_variable();
        if (args.argc > 0) {
          os << args[0];
          for (int i = 1; i < args.argc; i++) {
            os << args[i];
          }
        }
        break;
      }
    }
    return os;
  }
  
  
  // static
  List<const char*>* FlagList::argv() {
    List<const char*>* args = new List<const char*>(8);
    Flag* args_flag = NULL;
    for (size_t i = 0; i < num_flags; ++i) {
      Flag* f = &flags[i];
      if (!f->IsDefault()) {
        if (f->type() == Flag::TYPE_ARGS) {
          DCHECK(args_flag == NULL);
          args_flag = f;  // Must be last in arguments.
          continue;
        }
        {
          bool disabled = f->type() == Flag::TYPE_BOOL && !*f->bool_variable();
          std::ostringstream os;
          os << (disabled ? "--no" : "--") << f->name();
          args->Add(StrDup(os.str().c_str()));
        }
        if (f->type() != Flag::TYPE_BOOL) {
          std::ostringstream os;
          os << *f;
          args->Add(StrDup(os.str().c_str()));
        }
      }
    }
    if (args_flag != NULL) {
      std::ostringstream os;
      os << "--" << args_flag->name();
      args->Add(StrDup(os.str().c_str()));
      JSArguments jsargs = *args_flag->args_variable();
      for (int j = 0; j < jsargs.argc; j++) {
        args->Add(StrDup(jsargs[j]));
      }
    }
    return args;
  }
  
  
  inline char NormalizeChar(char ch) {
    return ch == '_' ? '-' : ch;
  }
  
  
  // Helper function to parse flags: Takes an argument arg and splits it into
  // a flag name and flag value (or NULL if they are missing). is_bool is set
  // if the arg started with "-no" or "--no". The buffer may be used to NUL-
  // terminate the name, it must be large enough to hold any possible name.
  static void SplitArgument(const char* arg,
                            char* buffer,
                            int buffer_size,
                            const char** name,
                            const char** value,
                            bool* is_bool) {
    *name = NULL;
    *value = NULL;
    *is_bool = false;
  
    if (arg != NULL && *arg == '-') {
      // find the begin of the flag name
      arg++;  // remove 1st '-'
      if (*arg == '-') {
        arg++;  // remove 2nd '-'
        if (arg[0] == '\0') {
          const char* kJSArgumentsFlagName = "js_arguments";
          *name = kJSArgumentsFlagName;
          return;
        }
      }
      if (arg[0] == 'n' && arg[1] == 'o') {
        arg += 2;  // remove "no"
        if (NormalizeChar(arg[0]) == '-') arg++;  // remove dash after "no".
        *is_bool = true;
      }
      *name = arg;
  
      // find the end of the flag name
      while (*arg != '\0' && *arg != '=')
        arg++;
  
      // get the value if any
      if (*arg == '=') {
        // make a copy so we can NUL-terminate flag name
        size_t n = arg - *name;
        CHECK(n < static_cast<size_t>(buffer_size));  // buffer is too small
        MemCopy(buffer, *name, n);
        buffer[n] = '\0';
        *name = buffer;
        // get the value
        *value = arg + 1;
      }
    }
  }
  
  
  static bool EqualNames(const char* a, const char* b) {
    for (int i = 0; NormalizeChar(a[i]) == NormalizeChar(b[i]); i++) {
      if (a[i] == '\0') {
        return true;
      }
    }
    return false;
  }
  
  
  static Flag* FindFlag(const char* name) {
    for (size_t i = 0; i < num_flags; ++i) {
      if (EqualNames(name, flags[i].name()))
        return &flags[i];
    }
    return NULL;
  }
  
  
  // static
  int FlagList::SetFlagsFromCommandLine(int* argc,
                                        char** argv,
                                        bool remove_flags) {
    int return_code = 0;
    // parse arguments
    for (int i = 1; i < *argc;) {
      int j = i;  // j > 0
      const char* arg = argv[i++];
  
      // split arg into flag components
      char buffer[1*KB];
      const char* name;
      const char* value;
      bool is_bool;
      SplitArgument(arg, buffer, sizeof buffer, &name, &value, &is_bool);
  
      if (name != NULL) {
        // lookup the flag
        Flag* flag = FindFlag(name);
        if (flag == NULL) {
          if (remove_flags) {
            // We don't recognize this flag but since we're removing
            // the flags we recognize we assume that the remaining flags
            // will be processed somewhere else so this flag might make
            // sense there.
            continue;
          } else {
            PrintF(stderr, "Error: unrecognized flag %s\n"
                   "Try --help for options\n", arg);
            return_code = j;
            break;
          }
        }
  
        // if we still need a flag value, use the next argument if available
        if (flag->type() != Flag::TYPE_BOOL &&
            flag->type() != Flag::TYPE_MAYBE_BOOL &&
            flag->type() != Flag::TYPE_ARGS &&
            value == NULL) {
          if (i < *argc) {
            value = argv[i++];
          }
          if (!value) {
            PrintF(stderr, "Error: missing value for flag %s of type %s\n"
                   "Try --help for options\n",
                   arg, Type2String(flag->type()));
            return_code = j;
            break;
          }
        }
  
        // set the flag
        char* endp = const_cast<char*>("");  // *endp is only read
        switch (flag->type()) {
          case Flag::TYPE_BOOL:
            *flag->bool_variable() = !is_bool;
            break;
          case Flag::TYPE_MAYBE_BOOL:
            *flag->maybe_bool_variable() = MaybeBoolFlag::Create(true, !is_bool);
            break;
          case Flag::TYPE_INT:
            *flag->int_variable() = strtol(value, &endp, 10);  // NOLINT
            break;
          case Flag::TYPE_FLOAT:
            *flag->float_variable() = strtod(value, &endp);
            break;
          case Flag::TYPE_STRING:
            flag->set_string_value(value ? StrDup(value) : NULL, true);
            break;
          case Flag::TYPE_ARGS: {
            int start_pos = (value == NULL) ? i : i - 1;
            int js_argc = *argc - start_pos;
            const char** js_argv = NewArray<const char*>(js_argc);
            if (value != NULL) {
              js_argv[0] = StrDup(value);
            }
            for (int k = i; k < *argc; k++) {
              js_argv[k - start_pos] = StrDup(argv[k]);
            }
            *flag->args_variable() = JSArguments::Create(js_argc, js_argv);
            i = *argc;  // Consume all arguments
            break;
          }
        }
  
        // handle errors
        bool is_bool_type = flag->type() == Flag::TYPE_BOOL ||
            flag->type() == Flag::TYPE_MAYBE_BOOL;
        if ((is_bool_type && value != NULL) || (!is_bool_type && is_bool) ||
            *endp != '\0') {
          PrintF(stderr, "Error: illegal value for flag %s of type %s\n"
                 "Try --help for options\n",
                 arg, Type2String(flag->type()));
          return_code = j;
          break;
        }
  
        // remove the flag & value from the command
        if (remove_flags) {
          while (j < i) {
            argv[j++] = NULL;
          }
        }
      }
    }
  
    // shrink the argument list
    if (remove_flags) {
      int j = 1;
      for (int i = 1; i < *argc; i++) {
        if (argv[i] != NULL)
          argv[j++] = argv[i];
      }
      *argc = j;
    }
  
    if (FLAG_help) {
      PrintHelp();
      exit(0);
    }
    // parsed all flags successfully
    return return_code;
  }
  
  
  static char* SkipWhiteSpace(char* p) {
    while (*p != '\0' && isspace(*p) != 0) p++;
    return p;
  }
  
  
  static char* SkipBlackSpace(char* p) {
    while (*p != '\0' && isspace(*p) == 0) p++;
    return p;
  }
  
  
  // static
  int FlagList::SetFlagsFromString(const char* str, int len) {
    // make a 0-terminated copy of str
    ScopedVector<char> copy0(len + 1);
    MemCopy(copy0.start(), str, len);
    copy0[len] = '\0';
  
    // strip leading white space
    char* copy = SkipWhiteSpace(copy0.start());
  
    // count the number of 'arguments'
    int argc = 1;  // be compatible with SetFlagsFromCommandLine()
    for (char* p = copy; *p != '\0'; argc++) {
      p = SkipBlackSpace(p);
      p = SkipWhiteSpace(p);
    }
  
    // allocate argument array
    ScopedVector<char*> argv(argc);
  
    // split the flags string into arguments
    argc = 1;  // be compatible with SetFlagsFromCommandLine()
    for (char* p = copy; *p != '\0'; argc++) {
      argv[argc] = p;
      p = SkipBlackSpace(p);
      if (*p != '\0') *p++ = '\0';  // 0-terminate argument
      p = SkipWhiteSpace(p);
    }
  
    // set the flags
    int result = SetFlagsFromCommandLine(&argc, argv.start(), false);
  
    return result;
  }
  
  
  // static
  void FlagList::ResetAllFlags() {
    for (size_t i = 0; i < num_flags; ++i) {
      flags[i].Reset();
    }
  }
  
  
  // static
  void FlagList::PrintHelp() {
    CpuFeatures::Probe(false);
    CpuFeatures::PrintTarget();
    CpuFeatures::PrintFeatures();
  
    OFStream os(stdout);
    os << "Usage:\n"
       << "  shell [options] -e string\n"
       << "    execute string in V8\n"
       << "  shell [options] file1 file2 ... filek\n"
       << "    run JavaScript scripts in file1, file2, ..., filek\n"
       << "  shell [options]\n"
       << "  shell [options] --shell [file1 file2 ... filek]\n"
       << "    run an interactive JavaScript shell\n"
       << "  d8 [options] file1 file2 ... filek\n"
       << "  d8 [options]\n"
       << "  d8 [options] --shell [file1 file2 ... filek]\n"
       << "    run the new debugging shell\n\n"
       << "Options:\n";
    for (size_t i = 0; i < num_flags; ++i) {
      Flag* f = &flags[i];
      os << "  --" << f->name() << " (" << f->comment() << ")\n"
         << "        type: " << Type2String(f->type()) << "  default: " << *f
         << "\n";
    }
  }
  
  
  // static
  void FlagList::EnforceFlagImplications() {
  #define FLAG_MODE_DEFINE_IMPLICATIONS
  #include "src/flag-definitions.h"
  #undef FLAG_MODE_DEFINE_IMPLICATIONS
  }
  
  
  uint32_t FlagList::Hash() {
    std::ostringstream modified_args_as_string;
  #ifdef DEBUG
    modified_args_as_string << "debug";
  #endif  // DEBUG
    for (size_t i = 0; i < num_flags; ++i) {
      Flag* current = &flags[i];
      if (!current->IsDefault()) {
        modified_args_as_string << i;
        modified_args_as_string << *current;
      }
    }
    std::string args(modified_args_as_string.str());
    return static_cast<uint32_t>(
        base::hash_range(args.c_str(), args.c_str() + args.length()));
  }
  } }  // namespace v8::internal
  