include/cripts/Context.hpp

/*
  Licensed to the Apache Software Foundation (ASF) under one
  or more contributor license agreements.  See the NOTICE file
  distributed with this work for additional information
  regarding copyright ownership.  The ASF licenses this file
  to you 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.
*/
#pragma once

#include <array>
#include <variant>
#include "ts/ts.h"
#include "ts/remap.h"

#include "cripts/Instance.hpp"
#include "cripts/Headers.hpp"
#include "cripts/Urls.hpp"
#include "cripts/Connections.hpp"

// These are pretty arbitrary for now
constexpr int CONTEXT_DATA_SLOTS = 4;

namespace cripts
{
class Context
{
  using self_type = Context;
  using DataType  = std::variant<integer, double, boolean, void *, cripts::string>;

public:
  Context()                         = delete;
  Context(const self_type &)        = delete;
  void operator=(const self_type &) = delete;

  // This will, and should, only be called via the ProxyAllocator as used in the factory.
  Context(TSHttpTxn txn_ptr, TSHttpSsn ssn_ptr, TSRemapRequestInfo *rri_ptr, cripts::Instance &inst)
    : rri(rri_ptr), p_instance(inst), _client(this), _server(this), _cache(this), _urls(this, _client.url)
  {
    state.txnp    = txn_ptr;
    state.ssnp    = ssn_ptr;
    state.context = this;
  }

  // Clear the cached header mloc's etc.
  void reset();

  // This uses the ProxyAllocator to create a new Context object.
  static self_type *Factory(TSHttpTxn txn_ptr, TSHttpSsn ssn_ptr, TSRemapRequestInfo *rri_ptr, cripts::Instance &inst);
  void              Release();

  // These fields are preserving the parameters as setup in DoRemap()
  cripts::Transaction                      state;           // This is the transaction state
  std::array<DataType, CONTEXT_DATA_SLOTS> data;            // Context data
  TSCont                                   contp = nullptr; // Remap or global continuation
  TSRemapRequestInfo                      *rri   = nullptr; // This may be nullptr, if not a remap
  cripts::Instance                        &p_instance;      // p_ == public_, since we can't use "instance"

  bool
  rriValid() const
  {
    return rri && rri->requestBufp && rri->requestHdrp && rri->requestUrl;
  }

  // These are private, but needs to be visible to our friend classes that
  // depends on the Context.
  friend class Client::Request;
  friend class Client::Response;
  friend class Client::Connection;
  friend class Client::URL;
  friend class Remap::From::URL;
  friend class Remap::To::URL;
  friend class Server::Request;
  friend class Server::Response;
  friend class Server::Connection;
  friend class Server::Response;
  friend class Cache::Response;
  friend class Cache::URL;
  friend class Pristine::URL;
  friend class Parent::URL;
  friend class Plugin::Remap;

  // These are "pre-allocated", but not initialized. They will be initialized
  // when used via a factory.
  struct _ClientBlock {
    cripts::Client::Response   response;
    cripts::Client::Request    request;
    cripts::Client::Connection connection;
    cripts::Client::URL        url;

    _ClientBlock(Context *ctx)
    {
      response.set_state(&ctx->state);
      request.set_state(&ctx->state);
      connection.set_state(&ctx->state);
    }
  } _client;

  struct _ServerBlock {
    cripts::Server::Response   response;
    cripts::Server::Request    request;
    cripts::Server::Connection connection;

    _ServerBlock(Context *ctx)
    {
      response.set_state(&ctx->state);
      request.set_state(&ctx->state);
      connection.set_state(&ctx->state);
    }

  } _server;

  struct _CacheBlock {
    cripts::Cache::Response response;
    cripts::Cache::URL      url;

    _CacheBlock(Context *ctx)
    {
      response.set_state(&ctx->state);
      url.set_context(ctx);
    }

  } _cache;

  struct _UrlBlock {
    cripts::Client::URL  &request;
    cripts::Pristine::URL pristine;
    cripts::Parent::URL   parent;

    struct {
      cripts::Remap::From::URL from;
      cripts::Remap::To::URL   to;
    } remap;

    _UrlBlock(Context *ctx, cripts::Client::URL &alias) : request(alias)
    {
      request.set_context(ctx);
      pristine.set_context(ctx);
      parent.set_context(ctx);
      remap.from.set_context(ctx);
      remap.to.set_context(ctx);
    }

  } _urls;
}; // End class Context

} // namespace cripts

// This may be weird, but oh well for now.
#define Get()               _get(context)
#define Set(_value, ...)    _set(context, _value __VA_OPT__(, ) __VA_ARGS__)
#define Update()            _update(context)
#define RunRemap()          _runRemap(context)
#define Activate()          _activate(context->p_instance)
#define CDebug(...)         context->p_instance.debug(__VA_ARGS__)
#define CDebugOn()          context->p_instance.debugOn()
#define DisableCallback(cb) context->state.disableCallback(cb)
#define transaction         context->state
#define txn_data            context->data
#define instance            context->p_instance