--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/lib/pingpong.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,517 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ *   'pingpong' is for generic back-and-forth support functions used by FTP,
+ *   IMAP, POP3, SMTP and whatever more that likes them.
+ *
+ ***************************************************************************/
+
+#include "curl_setup.h"
+
+#include "urldata.h"
+#include "sendf.h"
+#include "select.h"
+#include "progress.h"
+#include "speedcheck.h"
+#include "pingpong.h"
+#include "multiif.h"
+#include "non-ascii.h"
+#include "vtls/vtls.h"
+
+/* The last 3 #include files should be in this order */
+#include "curl_printf.h"
+#include "curl_memory.h"
+#include "memdebug.h"
+
+#ifdef USE_PINGPONG
+
+/* Returns timeout in ms. 0 or negative number means the timeout has already
+   triggered */
+time_t Curl_pp_state_timeout(struct pingpong *pp, bool disconnecting)
+{
+  struct connectdata *conn = pp->conn;
+  struct Curl_easy *data = conn->data;
+  time_t timeout_ms; /* in milliseconds */
+  long response_time = (data->set.server_response_timeout)?
+    data->set.server_response_timeout: pp->response_time;
+
+  /* if CURLOPT_SERVER_RESPONSE_TIMEOUT is set, use that to determine
+     remaining time, or use pp->response because SERVER_RESPONSE_TIMEOUT is
+     supposed to govern the response for any given server response, not for
+     the time from connect to the given server response. */
+
+  /* Without a requested timeout, we only wait 'response_time' seconds for the
+     full response to arrive before we bail out */
+  timeout_ms = response_time -
+    (time_t)Curl_timediff(Curl_now(), pp->response); /* spent time */
+
+  if(data->set.timeout && !disconnecting) {
+    /* if timeout is requested, find out how much remaining time we have */
+    time_t timeout2_ms = data->set.timeout - /* timeout time */
+      (time_t)Curl_timediff(Curl_now(), conn->now); /* spent time */
+
+    /* pick the lowest number */
+    timeout_ms = CURLMIN(timeout_ms, timeout2_ms);
+  }
+
+  return timeout_ms;
+}
+
+/*
+ * Curl_pp_statemach()
+ */
+CURLcode Curl_pp_statemach(struct pingpong *pp, bool block,
+                           bool disconnecting)
+{
+  struct connectdata *conn = pp->conn;
+  curl_socket_t sock = conn->sock[FIRSTSOCKET];
+  int rc;
+  time_t interval_ms;
+  time_t timeout_ms = Curl_pp_state_timeout(pp, disconnecting);
+  struct Curl_easy *data = conn->data;
+  CURLcode result = CURLE_OK;
+
+  if(timeout_ms <= 0) {
+    failf(data, "server response timeout");
+    return CURLE_OPERATION_TIMEDOUT; /* already too little time */
+  }
+
+  if(block) {
+    interval_ms = 1000;  /* use 1 second timeout intervals */
+    if(timeout_ms < interval_ms)
+      interval_ms = timeout_ms;
+  }
+  else
+    interval_ms = 0; /* immediate */
+
+  if(Curl_ssl_data_pending(conn, FIRSTSOCKET))
+    rc = 1;
+  else if(Curl_pp_moredata(pp))
+    /* We are receiving and there is data in the cache so just read it */
+    rc = 1;
+  else if(!pp->sendleft && Curl_ssl_data_pending(conn, FIRSTSOCKET))
+    /* We are receiving and there is data ready in the SSL library */
+    rc = 1;
+  else
+    rc = Curl_socket_check(pp->sendleft?CURL_SOCKET_BAD:sock, /* reading */
+                           CURL_SOCKET_BAD,
+                           pp->sendleft?sock:CURL_SOCKET_BAD, /* writing */
+                           interval_ms);
+
+  if(block) {
+    /* if we didn't wait, we don't have to spend time on this now */
+    if(Curl_pgrsUpdate(conn))
+      result = CURLE_ABORTED_BY_CALLBACK;
+    else
+      result = Curl_speedcheck(data, Curl_now());
+
+    if(result)
+      return result;
+  }
+
+  if(rc == -1) {
+    failf(data, "select/poll error");
+    result = CURLE_OUT_OF_MEMORY;
+  }
+  else if(rc)
+    result = pp->statemach_act(conn);
+
+  return result;
+}
+
+/* initialize stuff to prepare for reading a fresh new response */
+void Curl_pp_init(struct pingpong *pp)
+{
+  struct connectdata *conn = pp->conn;
+  pp->nread_resp = 0;
+  pp->linestart_resp = conn->data->state.buffer;
+  pp->pending_resp = TRUE;
+  pp->response = Curl_now(); /* start response time-out now! */
+}
+
+
+
+/***********************************************************************
+ *
+ * Curl_pp_vsendf()
+ *
+ * Send the formatted string as a command to a pingpong server. Note that
+ * the string should not have any CRLF appended, as this function will
+ * append the necessary things itself.
+ *
+ * made to never block
+ */
+CURLcode Curl_pp_vsendf(struct pingpong *pp,
+                        const char *fmt,
+                        va_list args)
+{
+  ssize_t bytes_written;
+  size_t write_len;
+  char *fmt_crlf;
+  char *s;
+  CURLcode result;
+  struct connectdata *conn = pp->conn;
+  struct Curl_easy *data;
+
+#ifdef HAVE_GSSAPI
+  enum protection_level data_sec;
+#endif
+
+  DEBUGASSERT(pp->sendleft == 0);
+  DEBUGASSERT(pp->sendsize == 0);
+  DEBUGASSERT(pp->sendthis == NULL);
+
+  if(!conn)
+    /* can't send without a connection! */
+    return CURLE_SEND_ERROR;
+
+  data = conn->data;
+
+  fmt_crlf = aprintf("%s\r\n", fmt); /* append a trailing CRLF */
+  if(!fmt_crlf)
+    return CURLE_OUT_OF_MEMORY;
+
+  s = vaprintf(fmt_crlf, args); /* trailing CRLF appended */
+  free(fmt_crlf);
+  if(!s)
+    return CURLE_OUT_OF_MEMORY;
+
+  bytes_written = 0;
+  write_len = strlen(s);
+
+  Curl_pp_init(pp);
+
+  result = Curl_convert_to_network(data, s, write_len);
+  /* Curl_convert_to_network calls failf if unsuccessful */
+  if(result) {
+    free(s);
+    return result;
+  }
+
+#ifdef HAVE_GSSAPI
+  conn->data_prot = PROT_CMD;
+#endif
+  result = Curl_write(conn, conn->sock[FIRSTSOCKET], s, write_len,
+                     &bytes_written);
+#ifdef HAVE_GSSAPI
+  data_sec = conn->data_prot;
+  DEBUGASSERT(data_sec > PROT_NONE && data_sec < PROT_LAST);
+  conn->data_prot = data_sec;
+#endif
+
+  if(result) {
+    free(s);
+    return result;
+  }
+
+  if(conn->data->set.verbose)
+    Curl_debug(conn->data, CURLINFO_HEADER_OUT, s, (size_t)bytes_written);
+
+  if(bytes_written != (ssize_t)write_len) {
+    /* the whole chunk was not sent, keep it around and adjust sizes */
+    pp->sendthis = s;
+    pp->sendsize = write_len;
+    pp->sendleft = write_len - bytes_written;
+  }
+  else {
+    free(s);
+    pp->sendthis = NULL;
+    pp->sendleft = pp->sendsize = 0;
+    pp->response = Curl_now();
+  }
+
+  return CURLE_OK;
+}
+
+
+/***********************************************************************
+ *
+ * Curl_pp_sendf()
+ *
+ * Send the formatted string as a command to a pingpong server. Note that
+ * the string should not have any CRLF appended, as this function will
+ * append the necessary things itself.
+ *
+ * made to never block
+ */
+CURLcode Curl_pp_sendf(struct pingpong *pp,
+                       const char *fmt, ...)
+{
+  CURLcode result;
+  va_list ap;
+  va_start(ap, fmt);
+
+  result = Curl_pp_vsendf(pp, fmt, ap);
+
+  va_end(ap);
+
+  return result;
+}
+
+/*
+ * Curl_pp_readresp()
+ *
+ * Reads a piece of a server response.
+ */
+CURLcode Curl_pp_readresp(curl_socket_t sockfd,
+                          struct pingpong *pp,
+                          int *code, /* return the server code if done */
+                          size_t *size) /* size of the response */
+{
+  ssize_t perline; /* count bytes per line */
+  bool keepon = TRUE;
+  ssize_t gotbytes;
+  char *ptr;
+  struct connectdata *conn = pp->conn;
+  struct Curl_easy *data = conn->data;
+  char * const buf = data->state.buffer;
+  CURLcode result = CURLE_OK;
+
+  *code = 0; /* 0 for errors or not done */
+  *size = 0;
+
+  ptr = buf + pp->nread_resp;
+
+  /* number of bytes in the current line, so far */
+  perline = (ssize_t)(ptr-pp->linestart_resp);
+
+  while((pp->nread_resp < (size_t)data->set.buffer_size) &&
+        (keepon && !result)) {
+
+    if(pp->cache) {
+      /* we had data in the "cache", copy that instead of doing an actual
+       * read
+       *
+       * pp->cache_size is cast to ssize_t here.  This should be safe, because
+       * it would have been populated with something of size int to begin
+       * with, even though its datatype may be larger than an int.
+       */
+      if((ptr + pp->cache_size) > (buf + data->set.buffer_size + 1)) {
+        failf(data, "cached response data too big to handle");
+        return CURLE_RECV_ERROR;
+      }
+      memcpy(ptr, pp->cache, pp->cache_size);
+      gotbytes = (ssize_t)pp->cache_size;
+      free(pp->cache);    /* free the cache */
+      pp->cache = NULL;   /* clear the pointer */
+      pp->cache_size = 0; /* zero the size just in case */
+    }
+    else {
+#ifdef HAVE_GSSAPI
+      enum protection_level prot = conn->data_prot;
+      conn->data_prot = PROT_CLEAR;
+#endif
+      DEBUGASSERT((ptr + data->set.buffer_size - pp->nread_resp) <=
+                  (buf + data->set.buffer_size + 1));
+      result = Curl_read(conn, sockfd, ptr,
+                         data->set.buffer_size - pp->nread_resp,
+                         &gotbytes);
+#ifdef HAVE_GSSAPI
+      DEBUGASSERT(prot  > PROT_NONE && prot < PROT_LAST);
+      conn->data_prot = prot;
+#endif
+      if(result == CURLE_AGAIN)
+        return CURLE_OK; /* return */
+
+      if(!result && (gotbytes > 0))
+        /* convert from the network encoding */
+        result = Curl_convert_from_network(data, ptr, gotbytes);
+      /* Curl_convert_from_network calls failf if unsuccessful */
+
+      if(result)
+        /* Set outer result variable to this error. */
+        keepon = FALSE;
+    }
+
+    if(!keepon)
+      ;
+    else if(gotbytes <= 0) {
+      keepon = FALSE;
+      result = CURLE_RECV_ERROR;
+      failf(data, "response reading failed");
+    }
+    else {
+      /* we got a whole chunk of data, which can be anything from one
+       * byte to a set of lines and possible just a piece of the last
+       * line */
+      ssize_t i;
+      ssize_t clipamount = 0;
+      bool restart = FALSE;
+
+      data->req.headerbytecount += (long)gotbytes;
+
+      pp->nread_resp += gotbytes;
+      for(i = 0; i < gotbytes; ptr++, i++) {
+        perline++;
+        if(*ptr == '\n') {
+          /* a newline is CRLF in pp-talk, so the CR is ignored as
+             the line isn't really terminated until the LF comes */
+
+          /* output debug output if that is requested */
+#ifdef HAVE_GSSAPI
+          if(!conn->sec_complete)
+#endif
+            if(data->set.verbose)
+              Curl_debug(data, CURLINFO_HEADER_IN,
+                         pp->linestart_resp, (size_t)perline);
+
+          /*
+           * We pass all response-lines to the callback function registered
+           * for "headers". The response lines can be seen as a kind of
+           * headers.
+           */
+          result = Curl_client_write(conn, CLIENTWRITE_HEADER,
+                                     pp->linestart_resp, perline);
+          if(result)
+            return result;
+
+          if(pp->endofresp(conn, pp->linestart_resp, perline, code)) {
+            /* This is the end of the last line, copy the last line to the
+               start of the buffer and zero terminate, for old times sake */
+            size_t n = ptr - pp->linestart_resp;
+            memmove(buf, pp->linestart_resp, n);
+            buf[n] = 0; /* zero terminate */
+            keepon = FALSE;
+            pp->linestart_resp = ptr + 1; /* advance pointer */
+            i++; /* skip this before getting out */
+
+            *size = pp->nread_resp; /* size of the response */
+            pp->nread_resp = 0; /* restart */
+            break;
+          }
+          perline = 0; /* line starts over here */
+          pp->linestart_resp = ptr + 1;
+        }
+      }
+
+      if(!keepon && (i != gotbytes)) {
+        /* We found the end of the response lines, but we didn't parse the
+           full chunk of data we have read from the server. We therefore need
+           to store the rest of the data to be checked on the next invoke as
+           it may actually contain another end of response already! */
+        clipamount = gotbytes - i;
+        restart = TRUE;
+        DEBUGF(infof(data, "Curl_pp_readresp_ %d bytes of trailing "
+                     "server response left\n",
+                     (int)clipamount));
+      }
+      else if(keepon) {
+
+        if((perline == gotbytes) && (gotbytes > data->set.buffer_size/2)) {
+          /* We got an excessive line without newlines and we need to deal
+             with it. We keep the first bytes of the line then we throw
+             away the rest. */
+          infof(data, "Excessive server response line length received, "
+                "%zd bytes. Stripping\n", gotbytes);
+          restart = TRUE;
+
+          /* we keep 40 bytes since all our pingpong protocols are only
+             interested in the first piece */
+          clipamount = 40;
+        }
+        else if(pp->nread_resp > (size_t)data->set.buffer_size/2) {
+          /* We got a large chunk of data and there's potentially still
+             trailing data to take care of, so we put any such part in the
+             "cache", clear the buffer to make space and restart. */
+          clipamount = perline;
+          restart = TRUE;
+        }
+      }
+      else if(i == gotbytes)
+        restart = TRUE;
+
+      if(clipamount) {
+        pp->cache_size = clipamount;
+        pp->cache = malloc(pp->cache_size);
+        if(pp->cache)
+          memcpy(pp->cache, pp->linestart_resp, pp->cache_size);
+        else
+          return CURLE_OUT_OF_MEMORY;
+      }
+      if(restart) {
+        /* now reset a few variables to start over nicely from the start of
+           the big buffer */
+        pp->nread_resp = 0; /* start over from scratch in the buffer */
+        ptr = pp->linestart_resp = buf;
+        perline = 0;
+      }
+
+    } /* there was data */
+
+  } /* while there's buffer left and loop is requested */
+
+  pp->pending_resp = FALSE;
+
+  return result;
+}
+
+int Curl_pp_getsock(struct pingpong *pp,
+                    curl_socket_t *socks)
+{
+  struct connectdata *conn = pp->conn;
+  socks[0] = conn->sock[FIRSTSOCKET];
+
+  if(pp->sendleft) {
+    /* write mode */
+    return GETSOCK_WRITESOCK(0);
+  }
+
+  /* read mode */
+  return GETSOCK_READSOCK(0);
+}
+
+CURLcode Curl_pp_flushsend(struct pingpong *pp)
+{
+  /* we have a piece of a command still left to send */
+  struct connectdata *conn = pp->conn;
+  ssize_t written;
+  curl_socket_t sock = conn->sock[FIRSTSOCKET];
+  CURLcode result = Curl_write(conn, sock, pp->sendthis + pp->sendsize -
+                               pp->sendleft, pp->sendleft, &written);
+  if(result)
+    return result;
+
+  if(written != (ssize_t)pp->sendleft) {
+    /* only a fraction was sent */
+    pp->sendleft -= written;
+  }
+  else {
+    free(pp->sendthis);
+    pp->sendthis = NULL;
+    pp->sendleft = pp->sendsize = 0;
+    pp->response = Curl_now();
+  }
+  return CURLE_OK;
+}
+
+CURLcode Curl_pp_disconnect(struct pingpong *pp)
+{
+  free(pp->cache);
+  pp->cache = NULL;
+  return CURLE_OK;
+}
+
+bool Curl_pp_moredata(struct pingpong *pp)
+{
+  return (!pp->sendleft && pp->cache && pp->nread_resp < pp->cache_size) ?
+         TRUE : FALSE;
+}
+
+#endif