/*
 * Copyright (C) 1999, 2000  Internet Software Consortium.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* $Id: dir.c,v 1.4 2000/02/03 23:08:11 halley Exp $ */

/* Principal Authors: DCL */

#include <string.h>

#include <isc/dir.h>
#include <isc/assertions.h>

#define ISC_DIR_MAGIC		0x4449522aU	/* DIR*. */
#define VALID_DIR(dir)		((dir) != NULL && \
				 (dir)->magic == ISC_DIR_MAGIC)

static isc_result_t
start_directory(isc_dir_t *p);

void
isc_dir_init(isc_dir_t *dir) {
	REQUIRE(dir != NULL);

	dir->dirname[0] = '\0';

	dir->entry.name[0] = '\0';
	dir->entry.length = 0;
	memset(&(dir->entry.find_data), 0, sizeof(dir->entry.find_data));

	dir->entry_filled = ISC_FALSE;
	dir->search_handle = INVALID_HANDLE_VALUE;

	dir->magic = ISC_DIR_MAGIC;
}

/*
 * Allocate workspace and open directory stream. If either one fails, 
 * NULL will be returned.
 */
isc_result_t
isc_dir_open(isc_dir_t *dir, const char *dirname) {
	char *p;
	isc_result_t result;

	REQUIRE(dirname != NULL);
	REQUIRE(VALID_DIR(dir) && dir->search_handle == INVALID_HANDLE_VALUE);

	/*
	 * Copy directory name.  Need to have enough space for the name,
	 * a possible path separator, the wildcard, and the final NUL.
	 */
	if (strlen(dirname) + 3 > sizeof(dir->dirname))
		/* XXXDCL ? */
		return (ISC_R_NOSPACE);
	strcpy(dir->dirname, dirname);

	/*
	 * Append path separator, if needed, and "*".
	 */
	p = dir->dirname + strlen(dir->dirname);
	if (dir->dirname < p && *(p - 1) != '\\' && *(p - 1) != ':')
		*p++ = '\\';
	*p++ = '*';
	*p++ = '\0';

	/*
	 * Open stream.
	 */
	result = start_directory(dir);

	return (result);
}

/*
 * Return previously retrieved file or get next one.  Unix's dirent has
 * separate open and read functions, but the Win32 and DOS interfaces open
 * the dir stream and reads the first file in one operation.
 */
isc_result_t
isc_dir_read(isc_dir_t *dir) {
	REQUIRE(VALID_DIR(dir) && dir->search_handle != INVALID_HANDLE_VALUE);

	if (dir->entry_filled)
		/*
		 * start_directory() already filled in the first entry.
		 */
		dir->entry_filled = ISC_FALSE;

	else {
		/*
		 * Fetch next file in directory.
		 */
		if (FindNextFile(dir->search_handle,
				 &dir->entry.find_data) == FALSE)
			/*
			 * Either the last file has been processed or
			 * an error has occured.  The former is not
			 * really an error, but the latter is.
			 */
			if (GetLastError() == ERROR_NO_MORE_FILES)
				return (ISC_R_NOMORE);
			else
				return (ISC_R_UNEXPECTED);
	}

	/*
	 * Make sure that the space for the name is long enough. 
	 */
	strcpy(dir->entry.name, dir->entry.find_data.cFileName);
	dir->entry.length = strlen(dir->entry.name);

	return (ISC_R_SUCCESS);
}

/*
 * Close directory stream.
 */
void
isc_dir_close(isc_dir_t *dir) {
       REQUIRE(VALID_DIR(dir) && dir->search_handle != INVALID_HANDLE_VALUE);

       FindClose(dir->search_handle);
       dir->search_handle = INVALID_HANDLE_VALUE;
}

/*
 * Reposition directory stream at start.
 */
isc_result_t
isc_dir_reset(isc_dir_t *dir) {
	isc_result_t result;

	REQUIRE(VALID_DIR(dir) && dir->search_handle != INVALID_HANDLE_VALUE);
	REQUIRE(dir->dirname != NULL);

	/*
	 * NT cannot reposition the seek pointer to the beginning of the
	 * the directory stream, but rather the directory needs to be
	 * closed and reopened.  The latter might fail.
	 */

	isc_dir_close(dir);

	result = start_directory(dir);

	return (result);
}

/*
 * Initialize isc_dir_t structure with new directory. The function
 * returns 0 on failure and nonzero on success.
 *
 * Note:
 * - Be sure to close previous stream before opening new one
 */
static isc_result_t
start_directory(isc_dir_t *dir)
{ 
	REQUIRE(VALID_DIR(dir));
	REQUIRE(dir->search_handle == INVALID_HANDLE_VALUE);

	dir->entry_filled = ISC_FALSE;

	/*
	 * Open stream and retrieve first file.
	 */
	dir->search_handle = FindFirstFile(dir->dirname,
					    &dir->entry.find_data);

	if (dir->search_handle == INVALID_HANDLE_VALUE) {
		/*
		 * Something went wrong but we don't know what. GetLastError()
		 * could give us more information about the error, but the
		 * MSDN documentation is frustratingly thin about what
		 * possible errors could have resulted.  (Score one for
		 * the Unix manual pages.)  So there is just this lame error
		 * instead of being able to differentiate ISC_R_NOTFOUND
		 * from ISC_R_UNEXPECTED.
		 */
		return (ISC_R_FAILURE);
	}

	/*
	 * Make sure that the space for the name is long enough. 
	 */
	INSIST(sizeof(dir->entry.name) >
	       strlen(dir->entry.find_data.cFileName));

	/*
	 * Fill in the data for the first entry of the directory.
	 */
	strcpy(dir->entry.name, dir->entry.find_data.cFileName);
	dir->entry.length = strlen(dir->entry.name);

	dir->entry_filled = ISC_TRUE;

	return (ISC_R_SUCCESS);
}

isc_result_t
isc_dir_chdir(const char *dirname) {
	/*
	 * Change the current directory to 'dirname'.
	 */

	REQUIRE(dirname != NULL);

	return (ISC_R_NOTIMPLEMENTED);
}