/*
 * curl.c
 * $Id$
 *
 * Copyright (c) 2005 Paul Guyot, The MacPorts Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of MacPorts Team nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#if HAVE_CONFIG_H
#include <config.h>
#endif

#include <ctype.h>
#include <errno.h>
#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <utime.h>

#include <curl/curl.h>

#include <tcl.h>

#include "curl.h"

/*
 * Some compiled-in constants that we may wish to change later, given more
 * empirical data.  These represent "best guess" values for now.
 */
#define _CURL_CONNECTION_TIMEOUT	((long)(30))		/* 30 seconds */
#define _CURL_MINIMUM_XFER_SPEED	((long)1024)		/* 1Kb/sec */
#define _CURL_MINIMUM_XFER_TIMEOUT	((long)(60))		/* 1 minute */

/* ========================================================================= **
 * Definitions
 * ========================================================================= */
#pragma mark Definitions

/* ------------------------------------------------------------------------- **
 * Prototypes
 * ------------------------------------------------------------------------- */
int SetResultFromCurlErrorCode(Tcl_Interp* interp, CURLcode inErrorCode);
int CurlFetchCmd(Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[]);
int CurlIsNewerCmd(Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[]);
int CurlGetSizeCmd(Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[]);

void CurlInit(void);

/* ========================================================================= **
 * Entry points
 * ========================================================================= */
#pragma mark -
#pragma mark Entry points

/**
 * Set the result if a libcurl error occurred return TCL_ERROR.
 * Otherwise, set the result to "" and return TCL_OK.
 *
 * @param interp		pointer to the interpreter.
 * @param inErrorCode	code of the error.
 * @return TCL_OK if inErrorCode is 0, TCL_ERROR otherwise.
 */
int
SetResultFromCurlErrorCode(Tcl_Interp *interp, CURLcode inErrorCode)
{
	int result = TCL_ERROR;

	if (inErrorCode == CURLE_OK) {
		Tcl_SetResult(interp, "", TCL_STATIC);
		result = TCL_OK;
	} else {
		Tcl_SetResult(interp, (char *)curl_easy_strerror(inErrorCode), TCL_VOLATILE);
	}

	return result;
}

/**
 * curl fetch subcommand entry point.
 *
 * syntax: curl fetch [-v] [--disable-epsv] [--ignore-ssl-cert] [--remote-time] [-u userpass] [--effective-url lasturlvar] url filename
 *
 * @param interp		current interpreter
 * @param objc			number of parameters
 * @param objv			parameters
 */
int
CurlFetchCmd(Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[])
{
	int theResult = TCL_OK;
	CURL* theHandle = NULL;
	FILE* theFile = NULL;
	bool performFailed = false;
	char theErrorString[CURL_ERROR_SIZE];

	do {
		int noprogress = 1;
		int useepsv = 1;
		int ignoresslcert = 0;
		int remotetime = 0;
		const char* theUserPassString = NULL;
		const char* effectiveURLVarName = NULL;
		char* effectiveURL = NULL;
		char* userAgent = PACKAGE_STRING " libcurl/" LIBCURL_VERSION;
		int optioncrsr;
		int lastoption;
		const char* theURL;
		const char* theFilePath;
		long theFileTime = 0;
		CURLcode theCurlCode;
		struct curl_slist *headers = NULL;

		/* we might have options and then the url and the file */
		/* let's process the options first */

		optioncrsr = 2;
		lastoption = objc - 3;
		while (optioncrsr <= lastoption) {
			/* get the option */
			const char* theOption = Tcl_GetString(objv[optioncrsr]);

			if (strcmp(theOption, "-v") == 0) {
				noprogress = 0;
			} else if (strcmp(theOption, "--disable-epsv") == 0) {
				useepsv = 0;
			} else if (strcmp(theOption, "--ignore-ssl-cert") == 0) {
				ignoresslcert = 1;
			} else if (strcmp(theOption, "--remote-time") == 0) {
				remotetime = 1;
			} else if (strcmp(theOption, "-u") == 0) {
				/* check we also have the parameter */
				if (optioncrsr < lastoption) {
					optioncrsr++;
					theUserPassString = Tcl_GetString(objv[optioncrsr]);
				} else {
					Tcl_SetResult(interp,
						"curl fetch: -u option requires a parameter",
						TCL_STATIC);
					theResult = TCL_ERROR;
					break;
				}
			} else if (strcmp(theOption, "--effective-url") == 0) {
				/* check we also have the parameter */
				if (optioncrsr < lastoption) {
					optioncrsr++;
					effectiveURLVarName = Tcl_GetString(objv[optioncrsr]);
				} else {
					Tcl_SetResult(interp,
						"curl fetch: --effective-url option requires a parameter",
						TCL_STATIC);
					theResult = TCL_ERROR;
					break;
				}
			} else if (strcmp(theOption, "--user-agent") == 0) {
				/* check we also have the parameter */
				if (optioncrsr < lastoption) {
					optioncrsr++;
					userAgent = Tcl_GetString(objv[optioncrsr]);
				} else {
					Tcl_SetResult(interp,
						"curl fetch: --user-agent option requires a parameter",
						TCL_STATIC);
					theResult = TCL_ERROR;
					break;
				}
			} else {
				Tcl_ResetResult(interp);
				Tcl_AppendResult(interp, "curl fetch: unknown option ", theOption, NULL);
				theResult = TCL_ERROR;
				break;
			}

			optioncrsr++;
		}

		if (optioncrsr <= lastoption) {
			/* something went wrong */
			break;
		}

		/*	first (second) parameter is -v or the url,
			second (third) parameter is the file */

		if (objc >= 4) {
			/* Retrieve the url */
			theURL = Tcl_GetString(objv[objc - 2]);

			/* Retrieve the file path */
			theFilePath = Tcl_GetString(objv[objc - 1]);
		} else {
			Tcl_WrongNumArgs(interp, 1, objv, "fetch [options] url file");
			theResult = TCL_ERROR;
			break;
		}

		/* Open the file */
		theFile = fopen( theFilePath, "w" );
		if (theFile == NULL) {
			Tcl_SetResult(interp, strerror(errno), TCL_VOLATILE);
			theResult = TCL_ERROR;
			break;
		}

		/* Create the CURL handle */
		theHandle = curl_easy_init();

		/* Setup the handle */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_URL, theURL);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

#if LIBCURL_VERSION_NUM >= 0x071304 && LIBCURL_VERSION_NUM <= 0x071307
        /* FTP_PROXY workaround for Snow Leopard */
        if (strncmp(theURL, "ftp:", 4) == 0) {
            char *ftp_proxy = getenv("FTP_PROXY");
            if (ftp_proxy) {
                theCurlCode = curl_easy_setopt(theHandle, CURLOPT_PROXY, ftp_proxy);
                if (theCurlCode != CURLE_OK) {
                    theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
                    break;
                }
            }
        }
#endif

		/* -L option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FOLLOWLOCATION, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* --max-redirs option, same default as curl command line */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_MAXREDIRS, 50);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* echo any cookies received on a redirect */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_COOKIEJAR, "/dev/null");
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* -f option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FAILONERROR, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* -A option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_USERAGENT, userAgent);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set timeout on connections */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_CONNECTTIMEOUT, _CURL_CONNECTION_TIMEOUT);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set minimum connection speed */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_LOW_SPEED_LIMIT, _CURL_MINIMUM_XFER_SPEED);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set timeout interval for connections < min xfer speed */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_LOW_SPEED_TIME, _CURL_MINIMUM_XFER_TIMEOUT);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* skip the header data */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_HEADER, 0);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* write to the file */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_WRITEDATA, theFile);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we want/don't want progress */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_NOPROGRESS, noprogress);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we want/don't want to use epsv */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FTP_USE_EPSV, useepsv);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we may want to ignore ssl errors */
		if (ignoresslcert) {
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_SSL_VERIFYPEER, (long) 0);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_SSL_VERIFYHOST, (long) 0);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
		}

		/* we want/don't want remote time */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FILETIME, remotetime);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set the l/p, if any */
		if (theUserPassString) {
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_USERPWD, theUserPassString);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
		}

		/* Clear the Pragma: no-cache header */
		headers = curl_slist_append(headers, "Pragma:");
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_HTTPHEADER, headers);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_ERRORBUFFER, theErrorString);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* actually fetch the resource */
		theCurlCode = curl_easy_perform(theHandle);
		if (theCurlCode != CURLE_OK) {
			performFailed = true;
			break;
		}

		/* close the file */
		(void) fclose( theFile );
		theFile = NULL;

#if LIBCURL_VERSION_NUM == 0x070d01 /* work around broken Tiger version of cURL */
		if (remotetime) {
			FILE *fp;
			char *tmp, *p;
			char buf[BUFSIZ];
			size_t size;

			tmp = tmpnam(NULL);
			fp = fopen(tmp, "w");
			if (fp == NULL) {
				Tcl_SetResult(interp, strerror(errno), TCL_VOLATILE);
				theResult = TCL_ERROR;
				break;
			}
			theFile = fopen( theFilePath, "r");
			if (theFile == NULL) {
				Tcl_SetResult(interp, strerror(errno), TCL_VOLATILE);
				theResult = TCL_ERROR;
				break;
			}
			if ( (p = fgets(buf, BUFSIZ, theFile)) != NULL) {
				/* skip stray header escaping into output */
				if (strncmp(p, "Last-Modified:", 14) != 0)
					rewind(theFile);
			}
			while ( (size = fread(buf, 1, BUFSIZ, theFile)) > 0) {
				fwrite(buf, 1, size, fp);
			}
			(void) fclose( theFile );
			theFile = NULL;
			fclose(fp);
			if (rename(tmp, theFilePath) != 0) {
				Tcl_SetResult(interp, strerror(errno), TCL_VOLATILE);
				theResult = TCL_ERROR;
				break;
			}
		}
#endif

		if (remotetime) {
			theCurlCode = curl_easy_getinfo(theHandle, CURLINFO_FILETIME, &theFileTime);
			if (theCurlCode == CURLE_OK && theFileTime > 0) {
				struct utimbuf times;
				times.actime = (time_t)theFileTime;
				times.modtime = (time_t)theFileTime;
				utime(theFilePath, &times); /* set the time we got */
			}
		}

		/* free header memory */
		curl_slist_free_all(headers);

		/* If --effective-url option was given, set given variable name to last effective url used by curl */
		if (effectiveURLVarName != NULL) {
			theCurlCode = curl_easy_getinfo(theHandle, CURLINFO_EFFECTIVE_URL, &effectiveURL);
			Tcl_SetVar(interp, effectiveURLVarName,
				(effectiveURL == NULL || theCurlCode != CURLE_OK) ? "" : effectiveURL,
				0);
		}

		/* clean up */
		curl_easy_cleanup( theHandle );
		theHandle = NULL;
	} while (0);

	if (performFailed) {
		Tcl_SetResult(interp, theErrorString, TCL_VOLATILE);
		theResult = TCL_ERROR;
	}

	if (theHandle != NULL) {
		curl_easy_cleanup( theHandle );
	}
	if (theFile != NULL) {
		fclose( theFile );
	}

	return theResult;
}

/**
 * curl isnewer subcommand entry point.
 *
 * @param interp		current interpreter
 * @param objc			number of parameters
 * @param objv			parameters
 */
int
CurlIsNewerCmd(Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[])
{
	int theResult = TCL_OK;
	CURL* theHandle = NULL;
	FILE* theFile = NULL;

	do {
		int optioncrsr;
		int lastoption;
		int ignoresslcert = 0;
		long theResponseCode = 0;
		const char* theURL;
		CURLcode theCurlCode;
		long theModDate;
		long userModDate;

		optioncrsr = 2;
		lastoption = objc - 3;
		while (optioncrsr <= lastoption) {
			/* get the option */
			const char* theOption = Tcl_GetString(objv[optioncrsr]);

			if (strcmp(theOption, "--ignore-ssl-cert") == 0) {
				ignoresslcert = 1;
			} else {
				Tcl_ResetResult(interp);
				Tcl_AppendResult(interp, "curl isnewer: unknown option ", theOption, NULL);
				theResult = TCL_ERROR;
				break;
			}

			optioncrsr++;
                }

		if (optioncrsr <= lastoption) {
			/* something went wrong */
			break;
		}

		/* first (second) parameter is the url, second (third) parameter is the date */
		if (objc < 4 || objc > 5) {
			Tcl_WrongNumArgs(interp, 1, objv, "isnewer [--ignore-ssl-cert] url date");
			theResult = TCL_ERROR;
			break;
		}

		/* Retrieve the url */
		theURL = Tcl_GetString(objv[objc - 2]);

		/* Get the date */
		theResult = Tcl_GetLongFromObj(interp, objv[objc - 1], &userModDate);
		if (theResult != TCL_OK) {
			break;
		}

		/* Open the file (dev/null) */
		theFile = fopen( "/dev/null", "a" );
		if (theFile == NULL) {
			Tcl_SetResult(interp, strerror(errno), TCL_VOLATILE);
			theResult = TCL_ERROR;
			break;
		}

		/* Create the CURL handle */
		theHandle = curl_easy_init();

		/* Setup the handle */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_URL, theURL);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* -L option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FOLLOWLOCATION, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* --max-redirs option, same default as curl command line */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_MAXREDIRS, 50);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* echo any cookies received on a redirect */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_COOKIEJAR, "/dev/null");
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* -f option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FAILONERROR, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set timeout on connections */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_CONNECTTIMEOUT, _CURL_CONNECTION_TIMEOUT);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set minimum connection speed */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_LOW_SPEED_LIMIT, _CURL_MINIMUM_XFER_SPEED);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set timeout interval for connections < min xfer speed */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_LOW_SPEED_TIME, _CURL_MINIMUM_XFER_TIMEOUT);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* write to the file */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_WRITEDATA, theFile);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we may want to ignore ssl errors */
		if (ignoresslcert) {
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_SSL_VERIFYPEER, (long) 0);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_SSL_VERIFYHOST, (long) 0);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
		}

		/* save the modification date */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FILETIME, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* skip the download if the file wasn't modified */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_TIMEVALUE, userModDate);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we do not want any progress */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_NOPROGRESS, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* actually fetch the resource */
		theCurlCode = curl_easy_perform(theHandle);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* close the file */
		(void) fclose( theFile );
		theFile = NULL;

		/* check everything went fine */
		theCurlCode = curl_easy_getinfo(theHandle, CURLINFO_HTTP_CODE, &theResponseCode);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		theModDate = -1;

		if (theResponseCode != 304) {
			/* get the modification date */
			theCurlCode = curl_easy_getinfo(theHandle, CURLINFO_FILETIME, &theModDate);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}

			/* clean up */
			curl_easy_cleanup( theHandle );
			theHandle = NULL;

			/* compare this with the date provided by user */
			if (theModDate < -1) {
				Tcl_SetResult(interp, "Couldn't get resource modification date", TCL_STATIC);
				theResult = TCL_ERROR;
				break;
			}
		}

		if (theModDate > userModDate) {
			Tcl_SetResult(interp, "1", TCL_STATIC);
		} else {
			Tcl_SetResult(interp, "0", TCL_STATIC);
		}
	} while (0);

	if (theHandle != NULL) {
		curl_easy_cleanup(theHandle);
	}

	if (theFile != NULL) {
		fclose(theFile);
	}

	return theResult;
}

/**
 * curl getsize subcommand entry point.
 *
 * @param interp		current interpreter
 * @param objc			number of parameters
 * @param objv			parameters
 */
int
CurlGetSizeCmd(Tcl_Interp* interp, int objc, Tcl_Obj* CONST objv[])
{
	int theResult = TCL_OK;
	CURL* theHandle = NULL;
	FILE* theFile = NULL;

	do {
		int optioncrsr;
		int lastoption;
		int ignoresslcert = 0;
		char theSizeString[32];
		const char* theURL;
		CURLcode theCurlCode;
		double theFileSize;

		optioncrsr = 2;
		lastoption = objc - 2;
		while (optioncrsr <= lastoption) {
			/* get the option */
			const char* theOption = Tcl_GetString(objv[optioncrsr]);

			if (strcmp(theOption, "--ignore-ssl-cert") == 0) {
				ignoresslcert = 1;
			} else {
				Tcl_ResetResult(interp);
				Tcl_AppendResult(interp, "curl getsize: unknown option ", theOption, NULL);
				theResult = TCL_ERROR;
				break;
			}

			optioncrsr++;
                }

		if (optioncrsr <= lastoption) {
			/* something went wrong */
			break;
		}

		/* first (second) parameter is the url */
		if (objc < 3 || objc > 4) {
			Tcl_WrongNumArgs(interp, 1, objv, "getsize [--ignore-ssl-cert] url");
			theResult = TCL_ERROR;
			break;
		}

		/* Retrieve the url */
		theURL = Tcl_GetString(objv[objc - 1]);

		/* Open the file (dev/null) */
		theFile = fopen( "/dev/null", "a" );
		if (theFile == NULL) {
			Tcl_SetResult(interp, strerror(errno), TCL_VOLATILE);
			theResult = TCL_ERROR;
			break;
		}

		/* Create the CURL handle */
		theHandle = curl_easy_init();

		/* Setup the handle */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_URL, theURL);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* -L option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FOLLOWLOCATION, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* --max-redirs option, same default as curl command line */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_MAXREDIRS, 50);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* echo any cookies received on a redirect */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_COOKIEJAR, "/dev/null");
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* -f option */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_FAILONERROR, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set timeout on connections */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_CONNECTTIMEOUT, _CURL_CONNECTION_TIMEOUT);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set minimum connection speed */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_LOW_SPEED_LIMIT, _CURL_MINIMUM_XFER_SPEED);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* set timeout interval for connections < min xfer speed */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_LOW_SPEED_TIME, _CURL_MINIMUM_XFER_TIMEOUT);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* write to the file */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_WRITEDATA, theFile);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we may want to ignore ssl errors */
		if (ignoresslcert) {
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_SSL_VERIFYPEER, (long) 0);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
			theCurlCode = curl_easy_setopt(theHandle, CURLOPT_SSL_VERIFYHOST, (long) 0);
			if (theCurlCode != CURLE_OK) {
				theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
				break;
			}
		}

		/* skip the header data */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_HEADER, 0);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* skip the body data */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_NOBODY, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* we do not want any progress */
		theCurlCode = curl_easy_setopt(theHandle, CURLOPT_NOPROGRESS, 1);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* actually fetch the resource */
		theCurlCode = curl_easy_perform(theHandle);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* close the file */
		(void) fclose( theFile );
		theFile = NULL;

		theFileSize = 0.0;

		/* get the file size */
		theCurlCode = curl_easy_getinfo(theHandle, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &theFileSize);
		if (theCurlCode != CURLE_OK) {
			theResult = SetResultFromCurlErrorCode(interp, theCurlCode);
			break;
		}

		/* clean up */
		curl_easy_cleanup( theHandle );
		theHandle = NULL;

		(void) snprintf(theSizeString, sizeof(theSizeString),
			"%.0f", theFileSize);
		Tcl_SetResult(interp, theSizeString, TCL_VOLATILE);
	} while (0);

	if (theHandle != NULL) {
		curl_easy_cleanup(theHandle);
	}

	if (theFile != NULL) {
		fclose(theFile);
	}

	return theResult;
}

/**
 * curl command entry point.
 *
 * @param clientData	custom data (ignored)
 * @param interp		current interpreter
 * @param objc			number of parameters
 * @param objv			parameters
 */
int
CurlCmd(
		ClientData clientData UNUSED,
		Tcl_Interp* interp,
		int objc,
		Tcl_Obj* CONST objv[])
{
	typedef enum {
		kCurlFetch,
		kCurlIsNewer,
		kCurlGetSize
	} EOption;

	static const char *options[] = {
		"fetch", "isnewer", "getsize", NULL
	};
	int theResult = TCL_OK;
	EOption theOptionIndex;
	static pthread_once_t once = PTHREAD_ONCE_INIT;

	/* TODO: use dispatch_once when we drop Leopard support */
	pthread_once(&once, CurlInit);

	if (objc < 3) {
		Tcl_WrongNumArgs(interp, 1, objv, "option ?arg ...?");
		return TCL_ERROR;
	}

	theResult = Tcl_GetIndexFromObj(
				interp,
				objv[1],
				options,
				"option",
				0,
				(int*) &theOptionIndex);
	if (theResult == TCL_OK) {
		switch (theOptionIndex) {
		case kCurlFetch:
			theResult = CurlFetchCmd(interp, objc, objv);
			break;
		case kCurlIsNewer:
			theResult = CurlIsNewerCmd(interp, objc, objv);
			break;
		case kCurlGetSize:
			theResult = CurlGetSizeCmd(interp, objc, objv);
			break;
		}
	}

	return theResult;
}

/**
 * curl init entry point.
 * libcurl will never be cleaned (where should I plug the hook?)
 */
void
CurlInit()
{
	curl_global_init(CURL_GLOBAL_ALL);
}