text: /*
   *
   * Copyright 2015 gRPC authors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   */
  
  #include <grpc/support/port_platform.h>
  
  #include "src/core/lib/channel/channel_args.h"
  
  #include <limits.h>
  #include <string.h>
  
  #include <map>
  #include <vector>
  
  #include "absl/strings/match.h"
  #include "absl/strings/str_format.h"
  #include "absl/strings/str_join.h"
  
  #include <grpc/impl/codegen/grpc_types.h>
  #include <grpc/support/alloc.h>
  #include <grpc/support/log.h>
  #include <grpc/support/string_util.h>
  
  #include "src/core/lib/gpr/string.h"
  #include "src/core/lib/gpr/useful.h"
  #include "src/core/lib/gprpp/match.h"
  
  namespace {
  
  int PointerCompare(void* a_ptr, const grpc_arg_pointer_vtable* a_vtable,
                     void* b_ptr, const grpc_arg_pointer_vtable* b_vtable) {
    int c = grpc_core::QsortCompare(a_ptr, b_ptr);
    if (c == 0) return 0;
    c = grpc_core::QsortCompare(a_vtable, b_vtable);
    if (c != 0) return c;
    return a_vtable->cmp(a_ptr, b_ptr);
  }
  
  }  // namespace
  
  namespace grpc_core {
  
  bool ChannelArgs::Pointer::operator==(const Pointer& rhs) const {
    return PointerCompare(p_, vtable_, rhs.p_, rhs.vtable_) == 0;
  }
  
  bool ChannelArgs::Pointer::operator<(const Pointer& rhs) const {
    return PointerCompare(p_, vtable_, rhs.p_, rhs.vtable_) < 0;
  }
  
  ChannelArgs::ChannelArgs() = default;
  
  ChannelArgs ChannelArgs::Set(grpc_arg arg) const {
    switch (arg.type) {
      case GRPC_ARG_INTEGER:
        return Set(arg.key, arg.value.integer);
      case GRPC_ARG_STRING:
        if (arg.value.string != nullptr) return Set(arg.key, arg.value.string);
        return Set(arg.key, "");
      case GRPC_ARG_POINTER:
        return Set(arg.key,
                   Pointer(arg.value.pointer.vtable->copy(arg.value.pointer.p),
                           arg.value.pointer.vtable));
    }
    GPR_UNREACHABLE_CODE(return ChannelArgs());
  }
  
  ChannelArgs ChannelArgs::FromC(const grpc_channel_args* args) {
    ChannelArgs result;
    if (args != nullptr) {
      for (size_t i = 0; i < args->num_args; i++) {
        result = result.Set(args->args[i]);
      }
    }
    return result;
  }
  
  const grpc_channel_args* ChannelArgs::ToC() const {
    std::vector<grpc_arg> c_args;
    args_.ForEach([&c_args](const std::string& key, const Value& value) {
      char* name = const_cast<char*>(key.c_str());
      c_args.push_back(Match(
          value,
          [name](int i) { return grpc_channel_arg_integer_create(name, i); },
          [name](const std::string& s) {
            return grpc_channel_arg_string_create(name,
                                                  const_cast<char*>(s.c_str()));
          },
          [name](const Pointer& p) {
            return grpc_channel_arg_pointer_create(name, p.c_pointer(),
                                                   p.c_vtable());
          }));
    });
    return grpc_channel_args_copy_and_add(nullptr, c_args.data(), c_args.size());
  }
  
  ChannelArgs ChannelArgs::Set(absl::string_view key, Value value) const {
    return ChannelArgs(args_.Add(std::string(key), std::move(value)));
  }
  
  ChannelArgs ChannelArgs::Set(absl::string_view key,
                               absl::string_view value) const {
    return Set(key, std::string(value));
  }
  
  ChannelArgs ChannelArgs::Set(absl::string_view key, const char* value) const {
    return Set(key, std::string(value));
  }
  
  ChannelArgs ChannelArgs::Set(absl::string_view key, std::string value) const {
    return Set(key, Value(std::move(value)));
  }
  
  ChannelArgs ChannelArgs::Remove(absl::string_view key) const {
    return ChannelArgs(args_.Remove(key));
  }
  
  absl::optional<int> ChannelArgs::GetInt(absl::string_view name) const {
    auto* v = Get(name);
    if (v == nullptr) return absl::nullopt;
    if (!absl::holds_alternative<int>(*v)) return absl::nullopt;
    return absl::get<int>(*v);
  }
  
  absl::optional<Duration> ChannelArgs::GetDurationFromIntMillis(
      absl::string_view name) const {
    auto ms = GetInt(name);
    if (!ms.has_value()) return absl::nullopt;
    if (*ms == INT_MAX) return Duration::Infinity();
    if (*ms == INT_MIN) return Duration::NegativeInfinity();
    return Duration::Milliseconds(*ms);
  }
  
  absl::optional<absl::string_view> ChannelArgs::GetString(
      absl::string_view name) const {
    auto* v = Get(name);
    if (v == nullptr) return absl::nullopt;
    if (!absl::holds_alternative<std::string>(*v)) return absl::nullopt;
    return absl::get<std::string>(*v);
  }
  
  void* ChannelArgs::GetVoidPointer(absl::string_view name) const {
    auto* v = Get(name);
    if (v == nullptr) return nullptr;
    if (!absl::holds_alternative<Pointer>(*v)) return nullptr;
    return absl::get<Pointer>(*v).c_pointer();
  }
  
  }  // namespace grpc_core
  
  static grpc_arg copy_arg(const grpc_arg* src) {
    grpc_arg dst;
    dst.type = src->type;
    dst.key = gpr_strdup(src->key);
    switch (dst.type) {
      case GRPC_ARG_STRING:
        dst.value.string = gpr_strdup(src->value.string);
        break;
      case GRPC_ARG_INTEGER:
        dst.value.integer = src->value.integer;
        break;
      case GRPC_ARG_POINTER:
        dst.value.pointer = src->value.pointer;
        dst.value.pointer.p =
            src->value.pointer.vtable->copy(src->value.pointer.p);
        break;
    }
    return dst;
  }
  
  grpc_channel_args* grpc_channel_args_copy_and_add(const grpc_channel_args* src,
                                                    const grpc_arg* to_add,
                                                    size_t num_to_add) {
    return grpc_channel_args_copy_and_add_and_remove(src, nullptr, 0, to_add,
                                                     num_to_add);
  }
  
  grpc_channel_args* grpc_channel_args_copy_and_remove(
      const grpc_channel_args* src, const char** to_remove,
      size_t num_to_remove) {
    return grpc_channel_args_copy_and_add_and_remove(src, to_remove,
                                                     num_to_remove, nullptr, 0);
  }
  
  static bool should_remove_arg(const grpc_arg* arg, const char** to_remove,
                                size_t num_to_remove) {
    for (size_t i = 0; i < num_to_remove; ++i) {
      if (strcmp(arg->key, to_remove[i]) == 0) return true;
    }
    return false;
  }
  
  grpc_channel_args* grpc_channel_args_copy_and_add_and_remove(
      const grpc_channel_args* src, const char** to_remove, size_t num_to_remove,
      const grpc_arg* to_add, size_t num_to_add) {
    // Figure out how many args we'll be copying.
    size_t num_args_to_copy = 0;
    if (src != nullptr) {
      for (size_t i = 0; i < src->num_args; ++i) {
        if (!should_remove_arg(&src->args[i], to_remove, num_to_remove)) {
          ++num_args_to_copy;
        }
      }
    }
    // Create result.
    grpc_channel_args* dst =
        static_cast<grpc_channel_args*>(gpr_malloc(sizeof(grpc_channel_args)));
    dst->num_args = num_args_to_copy + num_to_add;
    if (dst->num_args == 0) {
      dst->args = nullptr;
      return dst;
    }
    dst->args =
        static_cast<grpc_arg*>(gpr_malloc(sizeof(grpc_arg) * dst->num_args));
    // Copy args from src that are not being removed.
    size_t dst_idx = 0;
    if (src != nullptr) {
      for (size_t i = 0; i < src->num_args; ++i) {
        if (!should_remove_arg(&src->args[i], to_remove, num_to_remove)) {
          dst->args[dst_idx++] = copy_arg(&src->args[i]);
        }
      }
    }
    // Add args from to_add.
    for (size_t i = 0; i < num_to_add; ++i) {
      dst->args[dst_idx++] = copy_arg(&to_add[i]);
    }
    GPR_ASSERT(dst_idx == dst->num_args);
    return dst;
  }
  
  grpc_channel_args* grpc_channel_args_copy(const grpc_channel_args* src) {
    return grpc_channel_args_copy_and_add(src, nullptr, 0);
  }
  
  grpc_channel_args* grpc_channel_args_union(const grpc_channel_args* a,
                                             const grpc_channel_args* b) {
    if (a == nullptr) return grpc_channel_args_copy(b);
    if (b == nullptr) return grpc_channel_args_copy(a);
    const size_t max_out = (a->num_args + b->num_args);
    grpc_arg* uniques =
        static_cast<grpc_arg*>(gpr_malloc(sizeof(*uniques) * max_out));
    for (size_t i = 0; i < a->num_args; ++i) uniques[i] = a->args[i];
  
    size_t uniques_idx = a->num_args;
    for (size_t i = 0; i < b->num_args; ++i) {
      const char* b_key = b->args[i].key;
      if (grpc_channel_args_find(a, b_key) == nullptr) {  // not found
        uniques[uniques_idx++] = b->args[i];
      }
    }
    grpc_channel_args* result =
        grpc_channel_args_copy_and_add(nullptr, uniques, uniques_idx);
    gpr_free(uniques);
    return result;
  }
  
  static int cmp_arg(const grpc_arg* a, const grpc_arg* b) {
    int c = grpc_core::QsortCompare(a->type, b->type);
    if (c != 0) return c;
    c = strcmp(a->key, b->key);
    if (c != 0) return c;
    switch (a->type) {
      case GRPC_ARG_STRING:
        return strcmp(a->value.string, b->value.string);
      case GRPC_ARG_INTEGER:
        return grpc_core::QsortCompare(a->value.integer, b->value.integer);
      case GRPC_ARG_POINTER:
        return PointerCompare(a->value.pointer.p, a->value.pointer.vtable,
                              b->value.pointer.p, b->value.pointer.vtable);
    }
    GPR_UNREACHABLE_CODE(return 0);
  }
  
  /* stabilizing comparison function: since channel_args ordering matters for
   * keys with the same name, we need to preserve that ordering */
  static int cmp_key_stable(const void* ap, const void* bp) {
    const grpc_arg* const* a = static_cast<const grpc_arg* const*>(ap);
    const grpc_arg* const* b = static_cast<const grpc_arg* const*>(bp);
    int c = strcmp((*a)->key, (*b)->key);
    if (c == 0) c = grpc_core::QsortCompare(*a, *b);
    return c;
  }
  
  grpc_channel_args* grpc_channel_args_normalize(const grpc_channel_args* src) {
    grpc_arg** args =
        static_cast<grpc_arg**>(gpr_malloc(sizeof(grpc_arg*) * src->num_args));
    for (size_t i = 0; i < src->num_args; i++) {
      args[i] = &src->args[i];
    }
    if (src->num_args > 1) {
      qsort(args, src->num_args, sizeof(grpc_arg*), cmp_key_stable);
    }
  
    grpc_channel_args* b =
        static_cast<grpc_channel_args*>(gpr_malloc(sizeof(grpc_channel_args)));
    b->num_args = src->num_args;
    b->args = static_cast<grpc_arg*>(gpr_malloc(sizeof(grpc_arg) * b->num_args));
    for (size_t i = 0; i < src->num_args; i++) {
      b->args[i] = copy_arg(args[i]);
    }
  
    gpr_free(args);
    return b;
  }
  
  void grpc_channel_args_destroy(grpc_channel_args* a) {
    size_t i;
    if (!a) return;
    for (i = 0; i < a->num_args; i++) {
      switch (a->args[i].type) {
        case GRPC_ARG_STRING:
          gpr_free(a->args[i].value.string);
          break;
        case GRPC_ARG_INTEGER:
          break;
        case GRPC_ARG_POINTER:
          a->args[i].value.pointer.vtable->destroy(a->args[i].value.pointer.p);
          break;
      }
      gpr_free(a->args[i].key);
    }
    gpr_free(a->args);
    gpr_free(a);
  }
  
  int grpc_channel_args_compare(const grpc_channel_args* a,
                                const grpc_channel_args* b) {
    if (a == nullptr && b == nullptr) return 0;
    if (a == nullptr || b == nullptr) return a == nullptr ? -1 : 1;
    int c = grpc_core::QsortCompare(a->num_args, b->num_args);
    if (c != 0) return c;
    for (size_t i = 0; i < a->num_args; i++) {
      c = cmp_arg(&a->args[i], &b->args[i]);
      if (c != 0) return c;
    }
    return 0;
  }
  
  const grpc_arg* grpc_channel_args_find(const grpc_channel_args* args,
                                         const char* name) {
    if (args != nullptr) {
      for (size_t i = 0; i < args->num_args; ++i) {
        if (strcmp(args->args[i].key, name) == 0) {
          return &args->args[i];
        }
      }
    }
    return nullptr;
  }
  
  int grpc_channel_arg_get_integer(const grpc_arg* arg,
                                   const grpc_integer_options options) {
    if (arg == nullptr) return options.default_value;
    if (arg->type != GRPC_ARG_INTEGER) {
      gpr_log(GPR_ERROR, "%s ignored: it must be an integer", arg->key);
      return options.default_value;
    }
    if (arg->value.integer < options.min_value) {
      gpr_log(GPR_ERROR, "%s ignored: it must be >= %d", arg->key,
              options.min_value);
      return options.default_value;
    }
    if (arg->value.integer > options.max_value) {
      gpr_log(GPR_ERROR, "%s ignored: it must be <= %d", arg->key,
              options.max_value);
      return options.default_value;
    }
    return arg->value.integer;
  }
  
  int grpc_channel_args_find_integer(const grpc_channel_args* args,
                                     const char* name,
                                     const grpc_integer_options options) {
    const grpc_arg* arg = grpc_channel_args_find(args, name);
    return grpc_channel_arg_get_integer(arg, options);
  }
  
  char* grpc_channel_arg_get_string(const grpc_arg* arg) {
    if (arg == nullptr) return nullptr;
    if (arg->type != GRPC_ARG_STRING) {
      gpr_log(GPR_ERROR, "%s ignored: it must be an string", arg->key);
      return nullptr;
    }
    return arg->value.string;
  }
  
  char* grpc_channel_args_find_string(const grpc_channel_args* args,
                                      const char* name) {
    const grpc_arg* arg = grpc_channel_args_find(args, name);
    return grpc_channel_arg_get_string(arg);
  }
  
  bool grpc_channel_arg_get_bool(const grpc_arg* arg, bool default_value) {
    if (arg == nullptr) return default_value;
    if (arg->type != GRPC_ARG_INTEGER) {
      gpr_log(GPR_ERROR, "%s ignored: it must be an integer", arg->key);
      return default_value;
    }
    switch (arg->value.integer) {
      case 0:
        return false;
      case 1:
        return true;
      default:
        gpr_log(GPR_ERROR, "%s treated as bool but set to %d (assuming true)",
                arg->key, arg->value.integer);
        return true;
    }
  }
  
  bool grpc_channel_args_find_bool(const grpc_channel_args* args,
                                   const char* name, bool default_value) {
    const grpc_arg* arg = grpc_channel_args_find(args, name);
    return grpc_channel_arg_get_bool(arg, default_value);
  }
  
  bool grpc_channel_args_want_minimal_stack(const grpc_channel_args* args) {
    return grpc_channel_arg_get_bool(
        grpc_channel_args_find(args, GRPC_ARG_MINIMAL_STACK), false);
  }
  
  grpc_arg grpc_channel_arg_string_create(char* name, char* value) {
    grpc_arg arg;
    arg.type = GRPC_ARG_STRING;
    arg.key = name;
    arg.value.string = value;
    return arg;
  }
  
  grpc_arg grpc_channel_arg_integer_create(char* name, int value) {
    grpc_arg arg;
    arg.type = GRPC_ARG_INTEGER;
    arg.key = name;
    arg.value.integer = value;
    return arg;
  }
  
  grpc_arg grpc_channel_arg_pointer_create(
      char* name, void* value, const grpc_arg_pointer_vtable* vtable) {
    grpc_arg arg;
    arg.type = GRPC_ARG_POINTER;
    arg.key = name;
    arg.value.pointer.p = value;
    arg.value.pointer.vtable = vtable;
    return arg;
  }
  
  std::string grpc_channel_args_string(const grpc_channel_args* args) {
    if (args == nullptr) return "";
    std::vector<std::string> arg_strings;
    for (size_t i = 0; i < args->num_args; ++i) {
      const grpc_arg& arg = args->args[i];
      std::string arg_string;
      switch (arg.type) {
        case GRPC_ARG_INTEGER:
          arg_string = absl::StrFormat("%s=%d", arg.key, arg.value.integer);
          break;
        case GRPC_ARG_STRING:
          arg_string = absl::StrFormat("%s=%s", arg.key, arg.value.string);
          break;
        case GRPC_ARG_POINTER:
          arg_string = absl::StrFormat("%s=%p", arg.key, arg.value.pointer.p);
          break;
        default:
          arg_string = "arg with unknown type";
      }
      arg_strings.push_back(arg_string);
    }
    return absl::StrJoin(arg_strings, ", ");
  }
  
  namespace grpc_core {
  ChannelArgs ChannelArgsBuiltinPrecondition(const grpc_channel_args* src) {
    if (src == nullptr) return ChannelArgs();
    ChannelArgs output;
    std::map<absl::string_view, std::vector<absl::string_view>>
        concatenated_values;
    for (size_t i = 0; i < src->num_args; i++) {
      absl::string_view key = src->args[i].key;
      // User-agent strings were traditionally multi-valued and concatenated.
      // We preserve this behavior for backwards compatibility.
      if (key == GRPC_ARG_PRIMARY_USER_AGENT_STRING ||
          key == GRPC_ARG_SECONDARY_USER_AGENT_STRING) {
        if (src->args[i].type != GRPC_ARG_STRING) {
          gpr_log(GPR_ERROR, "Channel argument '%s' should be a string",
                  std::string(key).c_str());
        } else {
          concatenated_values[key].push_back(src->args[i].value.string);
        }
        continue;
      } else if (absl::StartsWith(key, "grpc.internal.")) {
        continue;
      }
      if (!output.Contains(key)) {
        output = output.Set(src->args[i]);
      } else {
        // Traditional grpc_channel_args_find behavior was to pick the first
        // value.
        // For compatibility with existing users, we will do the same here.
      }
    }
    // Concatenate the concatenated values.
    for (const auto& concatenated_value : concatenated_values) {
      output = output.Set(concatenated_value.first,
                          absl::StrJoin(concatenated_value.second, " "));
    }
    return output;
  }
  }  // namespace grpc_core
  
  namespace {
  grpc_channel_args_client_channel_creation_mutator g_mutator = nullptr;
  }  // namespace
  
  void grpc_channel_args_set_client_channel_creation_mutator(
      grpc_channel_args_client_channel_creation_mutator cb) {
    GPR_DEBUG_ASSERT(g_mutator == nullptr);
    g_mutator = cb;
  }
  grpc_channel_args_client_channel_creation_mutator
  grpc_channel_args_get_client_channel_creation_mutator() {
    return g_mutator;
  }
  