/* -------------------------------------------------------------------------- *\
 *
 * Patron HTTP Client: Interface to libcurl
 * Copyright (c) 2008 The Hive http://www.thehive.com/
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
\* -------------------------------------------------------------------------- */
#include <ruby.h>
#if defined(USE_TBR) && defined(HAVE_THREAD_H)
#include <ruby/thread.h>
#endif
#include <curl/curl.h>
#include "membuffer.h"
#include "sglib.h"  /* Simple Generic Library -> http://sglib.sourceforge.net */

#define UNUSED_ARGUMENT(x) (void)x

static VALUE mPatron = Qnil;
static VALUE mProxyType = Qnil;
static VALUE cSession = Qnil;
static VALUE cRequest = Qnil;
static VALUE ePatronError = Qnil;
static VALUE eUnsupportedProtocol = Qnil;
static VALUE eURLFormatError = Qnil;
static VALUE eHostResolutionError = Qnil;
static VALUE eConnectionFailed = Qnil;
static VALUE ePartialFileError = Qnil;
static VALUE eTimeoutError = Qnil;
static VALUE eTooManyRedirects = Qnil;


struct curl_state {
  CURL* handle;
  char* upload_buf;
  FILE* download_file;
  FILE* upload_file;
  FILE* debug_file;
  char error_buf[CURL_ERROR_SIZE];
  struct curl_slist* headers;
  struct curl_httppost* post;
  struct curl_httppost* last;
  membuffer header_buffer;
  membuffer body_buffer;
  int interrupt;
};


/*----------------------------------------------------------------------------*/
/* Curl Callbacks                                                             */

/* Takes data streamed from libcurl and writes it to a Ruby string buffer. */
static size_t session_write_handler(char* stream, size_t size, size_t nmemb, membuffer* buf) {
  int rc = membuffer_append(buf, stream, size * nmemb);

  /* return 0 to signal that we could not append data to our buffer */
  if (MB_OK != rc) { return 0; }

  /* otherwise, return the number of bytes appended */
  return size * nmemb;
}

static size_t session_read_handler(char* stream, size_t size, size_t nmemb, char **buffer) {
  size_t result = 0;

  if (buffer != NULL && *buffer != NULL) {
    size_t len = size * nmemb;
    char *s1 = strncpy(stream, *buffer, len);
    result = strlen(s1);
    *buffer += result;
  }

  return result;
}

/* A non-zero return value from the progress handler will terminate the current
 * request. We use this fact in order to interrupt any request when either the
 * user calls the "interrupt" method on the session or when the Ruby interpreter
 * is attempting to exit.
 */
static int session_progress_handler(void *clientp, double dltotal, double dlnow, double ultotal, double ulnow) {
  struct curl_state* state = (struct curl_state*) clientp;
  UNUSED_ARGUMENT(dltotal);
  UNUSED_ARGUMENT(dlnow);
  UNUSED_ARGUMENT(ultotal);
  UNUSED_ARGUMENT(ulnow);
  return state->interrupt;
}


/*----------------------------------------------------------------------------*/
/* List of active curl sessions                                               */

struct curl_state_list {
  struct curl_state       *state;
  struct curl_state_list  *next;
};

#define CS_LIST_COMPARATOR(p, _state_) (p->state - _state_)

static struct curl_state_list *cs_list = NULL;

static void cs_list_append( struct curl_state *state ) {
  struct curl_state_list *item = NULL;

  assert(state != NULL);
  item = ruby_xmalloc(sizeof(struct curl_state_list));
  item->state = state;
  item->next = NULL;

  SGLIB_LIST_ADD(struct curl_state_list, cs_list, item, next);
}

static void cs_list_remove(struct curl_state *state) {
  struct curl_state_list *item = NULL;

  assert(state != NULL);

  SGLIB_LIST_DELETE_IF_MEMBER(struct curl_state_list, cs_list, state, CS_LIST_COMPARATOR, next, item);
  if (item) {
    ruby_xfree(item);
  }
}

static void cs_list_interrupt(VALUE data) {
  UNUSED_ARGUMENT(data);

  SGLIB_LIST_MAP_ON_ELEMENTS(struct curl_state_list, cs_list, item, next, {
    item->state->interrupt = 1;
  });
}


/*----------------------------------------------------------------------------*/
/* Object allocation                                                          */

static void session_close_debug_file(struct curl_state *curl) {
  if (curl->debug_file && stderr != curl->debug_file) {
    fclose(curl->debug_file);
  }
  curl->debug_file = NULL;
}

/* Cleans up the Curl handle when the Session object is garbage collected. */
void session_free(struct curl_state *curl) {
  if (curl->handle) {
    curl_easy_cleanup(curl->handle);
    curl->handle = NULL;
  }

  session_close_debug_file(curl);

  membuffer_destroy( &curl->header_buffer );
  membuffer_destroy( &curl->body_buffer );

  cs_list_remove(curl);

  free(curl);
}

/* Allocates curl_state data needed for a new Session object. */
VALUE session_alloc(VALUE klass) {
  struct curl_state* curl;
  VALUE obj = Data_Make_Struct(klass, struct curl_state, NULL, session_free, curl);

  membuffer_init( &curl->header_buffer );
  membuffer_init( &curl->body_buffer );
  cs_list_append(curl);

  return obj;
}

/* Return the curl_state from the ruby VALUE which is the Session instance. */
static struct curl_state* get_curl_state(VALUE self) {
  struct curl_state *state;
  Data_Get_Struct(self, struct curl_state, state);

  if (NULL == state->handle) {
    state->handle = curl_easy_init();
    curl_easy_setopt(state->handle, CURLOPT_NOSIGNAL, 1);
    curl_easy_setopt(state->handle, CURLOPT_NOPROGRESS, 0);
    curl_easy_setopt(state->handle, CURLOPT_PROGRESSFUNCTION, &session_progress_handler);
    curl_easy_setopt(state->handle, CURLOPT_PROGRESSDATA, state);
  }

  return state;
}


/*----------------------------------------------------------------------------*/
/* Method implementations                                                     */

/* call-seq:
 *    Patron.libcurl_version   -> version string
 *
 * Returns the version of the embedded libcurl as a string.
 */
static VALUE libcurl_version(VALUE klass) {
  char* value = curl_version();
  UNUSED_ARGUMENT(klass);
  return rb_str_new2(value);
}

/* call-seq:
 *    Session.escape( string )   -> escaped string
 *
 * URL escapes the provided string.
 */
static VALUE session_escape(VALUE self, VALUE value) {
  struct curl_state *state = get_curl_state(self);
  VALUE string = StringValue(value);
  char* escaped = NULL;
  VALUE retval = Qnil;

  escaped = curl_easy_escape(state->handle,
                             RSTRING_PTR(string),
                             (int) RSTRING_LEN(string));

  retval = rb_str_new2(escaped);
  curl_free(escaped);

  return retval;
}

/* call-seq:
 *    Session.unescape( string )   -> unescaped string
 *
 * Unescapes the provided string.
 */
static VALUE session_unescape(VALUE self, VALUE value) {
  struct curl_state *state = get_curl_state(self);
  VALUE string = StringValue(value);
  char* unescaped = NULL;
  VALUE retval = Qnil;

  unescaped = curl_easy_unescape(state->handle,
                                 RSTRING_PTR(string),
                                 (int) RSTRING_LEN(string),
                                 NULL);

  retval = rb_str_new2(unescaped);
  curl_free(unescaped);

  return retval;
}

/* Callback used to iterate over the HTTP headers and store them in an slist. */
static int each_http_header(VALUE header_key, VALUE header_value, VALUE self) {
  struct curl_state *state = get_curl_state(self);
  CURL* curl = state->handle;

  VALUE name = rb_obj_as_string(header_key);
  VALUE value = rb_obj_as_string(header_value);
  VALUE header_str = Qnil;

  if (rb_str_cmp(name, rb_str_new2("Accept-Encoding")) == 0) {
    if (rb_funcall(value, rb_intern("include?"), 1, rb_str_new2("gzip"))) {
      #ifdef CURLOPT_ACCEPT_ENCODING
        curl_easy_setopt(curl, CURLOPT_ACCEPT_ENCODING, "gzip");
      #elif defined CURLOPT_ENCODING
        curl_easy_setopt(curl, CURLOPT_ENCODING, "gzip");
      #else
        rb_raise(rb_eArgError,
                "The libcurl version installed doesn't support 'gzip'.");
      #endif
    }
  }

  header_str = rb_str_plus(name, rb_str_new2(": "));
  header_str = rb_str_plus(header_str, value);

  state->headers = curl_slist_append(state->headers, StringValuePtr(header_str));

  return 0;
}

static int formadd_values(VALUE data_key, VALUE data_value, VALUE self) {
  struct curl_state *state = get_curl_state(self);
  VALUE name = rb_obj_as_string(data_key);
  VALUE value = rb_obj_as_string(data_value);

  curl_formadd(&state->post, &state->last, CURLFORM_PTRNAME, RSTRING_PTR(name),
                CURLFORM_PTRCONTENTS, RSTRING_PTR(value), CURLFORM_END);

  return 0;
}

static int formadd_files(VALUE data_key, VALUE data_value, VALUE self) {
  struct curl_state *state = get_curl_state(self);
  VALUE name = rb_obj_as_string(data_key);
  VALUE value = rb_obj_as_string(data_value);

  curl_formadd(&state->post, &state->last, CURLFORM_PTRNAME, RSTRING_PTR(name),
                CURLFORM_FILE, RSTRING_PTR(value), CURLFORM_END);

  return 0;
}

static void set_chunked_encoding(struct curl_state *state) {
  state->headers = curl_slist_append(state->headers, "Transfer-Encoding: chunked");
}

static FILE* open_file(VALUE filename, const char* perms) {
  FILE* handle = fopen(StringValuePtr(filename), perms);
  if (!handle) {
    rb_raise(rb_eArgError, "Unable to open specified file.");
  }

  return handle;
}

/* Set the options on the Curl handle from a Request object. Takes each field
 * in the Request object and uses it to set the appropriate option on the Curl
 * handle.
 */
static void set_options_from_request(VALUE self, VALUE request) {
  struct curl_state *state = get_curl_state(self);
  CURL* curl = state->handle;

  ID    action                = Qnil;
  VALUE headers               = Qnil;
  VALUE url                   = Qnil;
  VALUE timeout               = Qnil;
  VALUE redirects             = Qnil;
  VALUE proxy                 = Qnil;
  VALUE proxy_type            = Qnil;
  VALUE credentials           = Qnil;
  VALUE ignore_content_length = Qnil;
  VALUE insecure              = Qnil;
  VALUE cacert                = Qnil;
  VALUE ssl_version           = Qnil;
  VALUE buffer_size           = Qnil;
  VALUE action_name           = rb_iv_get(request, "@action");

  headers = rb_iv_get(request, "@headers");
  if (!NIL_P(headers)) {
    if (rb_type(headers) != T_HASH) {
      rb_raise(rb_eArgError, "Headers must be passed in a hash.");
    }

    rb_hash_foreach(headers, each_http_header, self);
  }

  action = SYM2ID(action_name);
  if(rb_iv_get(request, "@force_ipv4")) {
    curl_easy_setopt(curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);
  }
  if (action == rb_intern("get")) {
    VALUE data = rb_iv_get(request, "@upload_data");
    VALUE download_file = rb_iv_get(request, "@file_name");

    curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
    if (!NIL_P(data)) {
      long len = RSTRING_LEN(data);
      state->upload_buf = StringValuePtr(data);
      curl_easy_setopt(curl, CURLOPT_UPLOAD, 1);
      curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "GET");
      curl_easy_setopt(curl, CURLOPT_READFUNCTION, &session_read_handler);
      curl_easy_setopt(curl, CURLOPT_READDATA, &state->upload_buf);
      curl_easy_setopt(curl, CURLOPT_INFILESIZE, len);
    }
    if (!NIL_P(download_file)) {
      state->download_file = open_file(download_file, "wb");
      curl_easy_setopt(curl, CURLOPT_WRITEDATA, state->download_file);
    } else {
      state->download_file = NULL;
    }
  } else if (action == rb_intern("post") || action == rb_intern("put")) {
    VALUE data = rb_iv_get(request, "@upload_data");
    VALUE filename = rb_iv_get(request, "@file_name");
    VALUE multipart = rb_iv_get(request, "@multipart");

    if (!NIL_P(data) && NIL_P(multipart)) {
      long len = RSTRING_LEN(data);

      state->upload_buf = StringValuePtr(data);

      if (action == rb_intern("post")) {
        curl_easy_setopt(curl, CURLOPT_POST, 1);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, state->upload_buf);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, len);
      } else {
        curl_easy_setopt(curl, CURLOPT_UPLOAD, 1);
        curl_easy_setopt(curl, CURLOPT_READFUNCTION, &session_read_handler);
        curl_easy_setopt(curl, CURLOPT_READDATA, &state->upload_buf);
        curl_easy_setopt(curl, CURLOPT_INFILESIZE, len);
      }
    } else if (!NIL_P(filename) && NIL_P(multipart)) {
      set_chunked_encoding(state);

      curl_easy_setopt(curl, CURLOPT_UPLOAD, 1);

      if (action == rb_intern("post")) {
        curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
      }

      state->upload_file = open_file(filename, "rb");
      curl_easy_setopt(curl, CURLOPT_READDATA, state->upload_file);
    } else if (!NIL_P(multipart)) {
      if (action == rb_intern("post")) {
        if(!NIL_P(data) && !NIL_P(filename)) {
          if (rb_type(data) == T_HASH && rb_type(filename) == T_HASH) {
            rb_hash_foreach(data, formadd_values, self);
            rb_hash_foreach(filename, formadd_files, self);
        } else {   rb_raise(rb_eArgError, "Data and Filename must be passed in a hash.");}
        }
        curl_easy_setopt(curl, CURLOPT_HTTPPOST, state->post);

      } else {
         rb_raise(rb_eArgError, "Multipart PUT not supported");
      }

    } else {
      rb_raise(rb_eArgError, "Must provide either data or a filename when doing a PUT or POST");
    }

  // support for data passed with a DELETE request (e.g.: used by elasticsearch)
  } else if (action == rb_intern("delete")) {
      VALUE data = rb_iv_get(request, "@upload_data");

      if (!NIL_P(data)) {
        long len = RSTRING_LEN(data);
        state->upload_buf = StringValuePtr(data);
        curl_easy_setopt(curl, CURLOPT_POST, 1);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDS, state->upload_buf);
        curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, len);
      }
      curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "DELETE");

  } else if (action == rb_intern("head")) {
    curl_easy_setopt(curl, CURLOPT_NOBODY, 1);
  } else {
    VALUE action_name = rb_funcall(request, rb_intern("action_name"), 0);
    curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, StringValuePtr(action_name));
  }

  curl_easy_setopt(curl, CURLOPT_HTTPHEADER, state->headers);
  curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, state->error_buf);

  url = rb_iv_get(request, "@url");
  if (NIL_P(url)) {
    rb_raise(rb_eArgError, "Must provide a URL");
  }
  curl_easy_setopt(curl, CURLOPT_URL, StringValuePtr(url));

  timeout = rb_iv_get(request, "@timeout");
  if (!NIL_P(timeout)) {
    curl_easy_setopt(curl, CURLOPT_TIMEOUT, FIX2INT(timeout));
  }

  timeout = rb_iv_get(request, "@connect_timeout");
  if (!NIL_P(timeout)) {
    curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, FIX2INT(timeout));
  }

  redirects = rb_iv_get(request, "@max_redirects");
  if (!NIL_P(redirects)) {
    int r = FIX2INT(redirects);
    curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, r == 0 ? 0 : 1);
    curl_easy_setopt(curl, CURLOPT_MAXREDIRS, r);
  }

  proxy = rb_iv_get(request, "@proxy");
  if (!NIL_P(proxy)) {
    curl_easy_setopt(curl, CURLOPT_PROXY, StringValuePtr(proxy));
  }

  proxy_type = rb_iv_get(request, "@proxy_type");
  if (!NIL_P(proxy_type)) {
    curl_easy_setopt(curl, CURLOPT_PROXYTYPE, FIX2INT(proxy_type));
  }

  credentials = rb_funcall(request, rb_intern("credentials"), 0);
  if (!NIL_P(credentials)) {
    curl_easy_setopt(curl, CURLOPT_HTTPAUTH, FIX2INT(rb_iv_get(request, "@auth_type")));
    curl_easy_setopt(curl, CURLOPT_USERPWD, StringValuePtr(credentials));
  }

  ignore_content_length = rb_iv_get(request, "@ignore_content_length");
  if (!NIL_P(ignore_content_length)) {
    curl_easy_setopt(curl, CURLOPT_IGNORE_CONTENT_LENGTH, 1);
  }

  insecure = rb_iv_get(request, "@insecure");
  if(!NIL_P(insecure)) {
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0);
    curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0);
  }

  ssl_version = rb_iv_get(request, "@ssl_version");
  if(!NIL_P(ssl_version)) {
    char* version = StringValuePtr(ssl_version);
    if(strcmp(version, "SSLv2") == 0) {
      curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_SSLv2);
    } else if(strcmp(version, "SSLv3") == 0) {
      curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_SSLv3);
    } else if(strcmp(version, "TLSv1") == 0) {
      curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);
    }
  }

  cacert = rb_iv_get(request, "@cacert");
  if(!NIL_P(cacert)) {
    curl_easy_setopt(curl, CURLOPT_CAINFO, StringValuePtr(cacert));
  }

  buffer_size = rb_iv_get(request, "@buffer_size");
  if (!NIL_P(buffer_size)) {
     curl_easy_setopt(curl, CURLOPT_BUFFERSIZE, FIX2INT(buffer_size));
  }

  if(state->debug_file) {
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
    curl_easy_setopt(curl, CURLOPT_STDERR, state->debug_file);
  }
}

/* Use the info in a Curl handle to create a new Response object. */
static VALUE create_response(VALUE self, CURL* curl, VALUE header_buffer, VALUE body_buffer) {
  VALUE args[6] = { Qnil, Qnil, Qnil, Qnil, Qnil, Qnil };
  char* effective_url = NULL;
  long code = 0;
  long count = 0;

  curl_easy_getinfo(curl, CURLINFO_EFFECTIVE_URL, &effective_url);
  args[0] = rb_str_new2(effective_url);

  curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
  args[1] = INT2NUM(code);

  curl_easy_getinfo(curl, CURLINFO_REDIRECT_COUNT, &count);
  args[2] = INT2NUM(count);

  args[3] = header_buffer;
  args[4] = body_buffer;
  args[5] = rb_iv_get(self, "@default_response_charset");

  return rb_class_new_instance(6, args, rb_const_get(mPatron, rb_intern("Response")));
}

/* Raise an exception based on the Curl error code. */
static VALUE select_error(CURLcode code) {
  VALUE error = Qnil;
  switch (code) {
    case CURLE_UNSUPPORTED_PROTOCOL:  error = eUnsupportedProtocol; break;
    case CURLE_URL_MALFORMAT:         error = eURLFormatError;      break;
    case CURLE_COULDNT_RESOLVE_HOST:  error = eHostResolutionError; break;
    case CURLE_COULDNT_CONNECT:       error = eConnectionFailed;    break;
    case CURLE_PARTIAL_FILE:          error = ePartialFileError;    break;
    case CURLE_OPERATION_TIMEDOUT:    error = eTimeoutError;        break;
    case CURLE_TOO_MANY_REDIRECTS:    error = eTooManyRedirects;    break;

    default: error = ePatronError;
  }

  return error;
}

/* Perform the actual HTTP request by calling libcurl. */
static VALUE perform_request(VALUE self) {
  struct curl_state *state = get_curl_state(self);
  CURL* curl = state->handle;
  membuffer* header_buffer = NULL;
  membuffer* body_buffer = NULL;
  CURLcode ret = 0;

  state->interrupt = 0;  /* clear any interrupt flags */

  header_buffer = &state->header_buffer;
  body_buffer = &state->body_buffer;

  membuffer_clear(header_buffer);
  membuffer_clear(body_buffer);

  /* headers */
  curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, &session_write_handler);
  curl_easy_setopt(curl, CURLOPT_HEADERDATA, header_buffer);

  /* body */
  if (!state->download_file) {
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, &session_write_handler);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, body_buffer);
  }

#if (defined(HAVE_TBR) || defined(HAVE_TCWOGVL)) && defined(USE_TBR)
#if defined(HAVE_TCWOGVL)
  ret = (CURLcode) rb_thread_call_without_gvl(
          (void *(*)(void *)) curl_easy_perform, curl,
          RUBY_UBF_IO, 0
        );
#else
  ret = (CURLcode) rb_thread_blocking_region(
          (rb_blocking_function_t*) curl_easy_perform, curl,
          RUBY_UBF_IO, 0
        );
#endif
#else
  ret = curl_easy_perform(curl);
#endif

  if (CURLE_OK == ret) {
    VALUE header_str = membuffer_to_rb_str(header_buffer);
    VALUE body_str = Qnil;
    if (!state->download_file) { body_str = membuffer_to_rb_str(body_buffer); }

    return create_response(self, curl, header_str, body_str);
  } else {
    rb_raise(select_error(ret), "%s", state->error_buf);
  }
}

/* Cleanup after each request by resetting the Curl handle and deallocating
 * all request related objects such as the header slist.
 */
static VALUE cleanup(VALUE self) {
  struct curl_state *state = get_curl_state(self);
  curl_easy_reset(state->handle);

  if (state->headers) {
    curl_slist_free_all(state->headers);
    state->headers = NULL;
  }

  if (state->download_file) {
    fclose(state->download_file);
    state->download_file = NULL;
  }

  if (state->upload_file) {
    fclose(state->upload_file);
    state->upload_file = NULL;
  }

  state->upload_buf = NULL;

  return Qnil;
}

/* call-seq:
 *    session.handle_request( request )   -> response
 *
 * Peform the actual HTTP request by calling libcurl. Each filed in the
 * +request+ object will be used to set the appropriate option on the libcurl
 * library. After the request completes, a Response object will be created and
 * returned.
 *
 * In the event of an error in the libcurl library, a Ruby exception will be
 * created and raised. The exception will return the libcurl error code and
 * error message.
 */
static VALUE session_handle_request(VALUE self, VALUE request) {
  set_options_from_request(self, request);
  return rb_ensure(&perform_request, self, &cleanup, self);
}

/* call-seq:
 *    session.reset   -> session
 *
 * Reset the underlying cURL session. This effectively closes all open
 * connections and disables debug output.
 */
static VALUE session_reset(VALUE self) {
  struct curl_state *state;
  Data_Get_Struct(self, struct curl_state, state);

  if (NULL != state->handle) {
    cleanup(self);
    curl_easy_cleanup(state->handle);
    state->handle = NULL;
    session_close_debug_file(state);
  }

  return self;
}

/* call-seq:
 *    session.interrupt   -> session
 *
 * Interrupt any currently executing request. This will cause the current
 * request to error and raise an exception.
 */
static VALUE session_interrupt(VALUE self) {
  struct curl_state *state = get_curl_state(self);
  state->interrupt = 1;
  return self;
}

/* call-seq:
 *    session.enable_cookie_session( file )   -> session
 *
 * Turn on cookie handling for this session, storing them in memory by
 * default or in +file+ if specified. The +file+ must be readable and
 * writable. Calling multiple times will add more files.
 */
static VALUE enable_cookie_session(VALUE self, VALUE file) {
  struct curl_state *state = get_curl_state(self);
  CURL* curl = state->handle;
  char* file_path = NULL;

  file_path = RSTRING_PTR(file);
  if (file_path != NULL && strlen(file_path) != 0) {
    curl_easy_setopt(curl, CURLOPT_COOKIEJAR, file_path);
  }
  curl_easy_setopt(curl, CURLOPT_COOKIEFILE, file_path);

  return self;
}

/* call-seq:
 *    session.set_debug_file( file )   -> session
 *
 * Enable debug output to stderr or to specified +file+.
 */
static VALUE set_debug_file(VALUE self, VALUE file) {
  struct curl_state *state = get_curl_state(self);
  char* file_path = RSTRING_PTR(file);

  session_close_debug_file(state);

  if(file_path != NULL && strlen(file_path) != 0) {
    state->debug_file = open_file(file, "wb");
  } else {
    state->debug_file = stderr;
  }

  return self;
}


/*----------------------------------------------------------------------------*/
/* Extension initialization                                                   */

void Init_session_ext() {
  curl_global_init(CURL_GLOBAL_ALL);
  rb_require("patron/error");

  rb_set_end_proc(&cs_list_interrupt, Qnil);

  mPatron = rb_define_module("Patron");

  ePatronError = rb_const_get(mPatron, rb_intern("Error"));

  eUnsupportedProtocol = rb_const_get(mPatron, rb_intern("UnsupportedProtocol"));
  eURLFormatError = rb_const_get(mPatron, rb_intern("URLFormatError"));
  eHostResolutionError = rb_const_get(mPatron, rb_intern("HostResolutionError"));
  eConnectionFailed = rb_const_get(mPatron, rb_intern("ConnectionFailed"));
  ePartialFileError = rb_const_get(mPatron, rb_intern("PartialFileError"));
  eTimeoutError = rb_const_get(mPatron, rb_intern("TimeoutError"));
  eTooManyRedirects = rb_const_get(mPatron, rb_intern("TooManyRedirects"));

  rb_define_module_function(mPatron, "libcurl_version", libcurl_version, 0);

  cSession = rb_define_class_under(mPatron, "Session", rb_cObject);
  cRequest = rb_define_class_under(mPatron, "Request", rb_cObject);
  rb_define_alloc_func(cSession, session_alloc);

  rb_define_method(cSession, "escape",         session_escape,         1);
  rb_define_method(cSession, "unescape",       session_unescape,       1);
  rb_define_method(cSession, "handle_request", session_handle_request, 1);
  rb_define_method(cSession, "reset",          session_reset,          0);
  rb_define_method(cSession, "interrupt",      session_interrupt,      0);
  rb_define_method(cSession, "enable_cookie_session", enable_cookie_session, 1);
  rb_define_method(cSession, "set_debug_file", set_debug_file, 1);
  rb_define_alias(cSession, "urlencode", "escape");
  rb_define_alias(cSession, "urldecode", "unescape");

  rb_define_const(cRequest, "AuthBasic",  INT2FIX(CURLAUTH_BASIC));
  rb_define_const(cRequest, "AuthDigest", INT2FIX(CURLAUTH_DIGEST));
  rb_define_const(cRequest, "AuthAny",    INT2FIX(CURLAUTH_ANY));

  mProxyType = rb_define_module_under(mPatron, "ProxyType");
  rb_define_const(mProxyType, "HTTP", INT2FIX(CURLPROXY_HTTP));
  rb_define_const(mProxyType, "HTTP_1_0", INT2FIX(CURLPROXY_HTTP_1_0));
  rb_define_const(mProxyType, "SOCKS4", INT2FIX(CURLPROXY_SOCKS4));
  rb_define_const(mProxyType, "SOCKS5", INT2FIX(CURLPROXY_SOCKS5));
  rb_define_const(mProxyType, "SOCKS4A", INT2FIX(CURLPROXY_SOCKS4A));
  rb_define_const(mProxyType, "SOCKS5_HOSTNAME", INT2FIX(CURLPROXY_SOCKS5_HOSTNAME));
}