/*-
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
 *
 * @(#)suff.c	8.4 (Berkeley) 3/21/94
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/usr.bin/make/suff.c 187475 2009-01-20 17:15:12Z rdivacky $");

/*-
 * suff.c --
 *	Functions to maintain suffix lists and find implicit dependents
 *	using suffix transformation rules
 *
 * Interface:
 *	Suff_Init 	    	Initialize all things to do with suffixes.
 *
 *	Suff_DoPaths	    	This function is used to make life easier
 *	    	  	    	when searching for a file according to its
 *	    	  	    	suffix. It takes the global search path,
 *	    	  	    	as defined using the .PATH: target, and appends
 *	    	  	    	its directories to the path of each of the
 *	    	  	    	defined suffixes, as specified using
 *	    	  	    	.PATH<suffix>: targets. In addition, all
 *	    	  	    	directories given for suffixes labeled as
 *	    	  	    	include files or libraries, using the .INCLUDES
 *	    	  	    	or .LIBS targets, are played with using
 *	    	  	    	Dir_MakeFlags to create the .INCLUDES and
 *	    	  	    	.LIBS global variables.
 *
 *	Suff_ClearSuffixes  	Clear out all the suffixes and defined
 *	    	  	    	transformations.
 *
 *	Suff_IsTransform    	Return TRUE if the passed string is the lhs
 *	    	  	    	of a transformation rule.
 *
 *	Suff_AddSuffix	    	Add the passed string as another known suffix.
 *
 *	Suff_GetPath	    	Return the search path for the given suffix.
 *
 *	Suff_AddInclude	    	Mark the given suffix as denoting an include
 *	    	  	    	file.
 *
 *	Suff_AddLib	    	Mark the given suffix as denoting a library.
 *
 *	Suff_AddTransform   	Add another transformation to the suffix
 *	    	  	    	graph. Returns  GNode suitable for framing, I
 *	    	  	    	mean, tacking commands, attributes, etc. on.
 *
 *	Suff_SetNull	    	Define the suffix to consider the suffix of
 *	    	  	    	any file that doesn't have a known one.
 *
 *	Suff_FindDeps	    	Find implicit sources for and the location of
 *	    	  	    	a target based on its suffix. Returns the
 *	    	  	    	bottom-most node added to the graph or NULL
 *	    	  	    	if the target had no implicit sources.
 */

#include <sys/queue.h>
#include <assert.h>
#include <string.h>
#include <stdlib.h>

#include "arch.h"
#include "buf.h"
#include "config.h"
#include "dir.h"
#include "globals.h"
#include "GNode.h"
#include "lst.h"
#include "make.h"
#include "parse.h"
#include "str.h"
#include "suff.h"
#include "targ.h"
#include "util.h"
#include "var.h"

/* Lst of suffixes */
static Lst sufflist = Lst_Initializer(sufflist);

/* Lst of suffixes to be cleaned */
static Lst suffClean = Lst_Initializer(suffClean);

/* Lst of sources */
static Lst srclist = Lst_Initializer(srclist);

/* Lst of transformation rules */
static Lst transforms = Lst_Initializer(transforms);

/* Counter for assigning suffix numbers */
static int sNum = 0;

/*
 * Structure describing an individual suffix.
 */
typedef struct Suff {
	char	*name;		/* The suffix itself */
	int	nameLen;	/* Length of the suffix */
	short	flags;		/* Type of suffix */
#define	SUFF_INCLUDE	0x01	/* One which is #include'd */
#define	SUFF_LIBRARY	0x02	/* One which contains a library */
#define	SUFF_NULL	0x04	/* The empty suffix */
	struct Path searchPath;	/* Path for files with this suffix */
	int	sNum;		/* The suffix number */
	int	refCount;	/* Reference count of list membership */
	Lst	parents;	/* Suffixes we have a transformation to */
	Lst	children;	/* Suffixes we have a transformation from */
	Lst	ref;		/* List of lists this suffix is referenced */
} Suff;

/*
 * Structure used in the search for implied sources.
 */
typedef struct Src {
	char	*file;		/* The file to look for */
	char	*pref;		/* Prefix from which file was formed */
	Suff	*suff;		/* The suffix on the file */
	struct Src *parent;	/* The Src for which this is a source */
	GNode	*node;		/* The node describing the file */
	int	children;	/* Count of existing children (so we don't free
				 * this thing too early or never nuke it) */
#ifdef DEBUG_SRC
	Lst	cp;		/* Debug; children list */
#endif
} Src;

/* The NULL suffix for this run */
static Suff	*suffNull;

/* The empty suffix required for POSIX single-suffix transformation rules */
static Suff	*emptySuff;

static void SuffFindDeps(GNode *, Lst *);


/*-
 *-----------------------------------------------------------------------
 * SuffSuffIsSuffix  --
 *	See if suff is a suffix of str.
 *
 * Results:
 *	NULL if it ain't, pointer to character in str before suffix if
 *	it is.
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
static char *
SuffSuffIsSuffix(const Suff *s, char *str)
{
	const char	*p1;	/* Pointer into suffix name */
	char		*p2;	/* Pointer into string being examined */
	size_t		len;

	len = strlen(str);
	p1 = s->name + s->nameLen;
	p2 = str + len;

	while (p1 >= s->name && len > 0 && *p1 == *p2) {
		p1--;
		p2--;
		len--;
	}

	return (p1 == s->name - 1 ? p2 : NULL);
}

/*-
 *-----------------------------------------------------------------------
 * SuffSuffFind --
 *	Find a suffix given its name.
 *
 * Results:
 *	The suffix or NULL.
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
static Suff *
SuffSuffFind(const char *s)
{
	LstNode	*ln;

	LST_FOREACH(ln, &sufflist) {
		if (strcmp(s, ((const Suff *)Lst_Datum(ln))->name) == 0)
			return (Lst_Datum(ln));
	}
	return (NULL);
}

/*-
 *-----------------------------------------------------------------------
 * SuffTransFind
 *	Find a transform.
 *
 * Results:
 *	transform or NULL.
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
static GNode *
SuffTransFind(const char *name)
{
	LstNode	*ln;

	LST_FOREACH(ln, &transforms) {
		if (strcmp(name, ((const GNode *)Lst_Datum(ln))->name) == 0)
			return (Lst_Datum(ln));
	}
	return (NULL);
}

 	    /*********** Maintenance Functions ************/

#if 0
/*
 * Keep this function for now until it is clear why a .SUFFIXES: doesn't
 * actually delete the suffixes but just puts them on the suffClean list.
 */
/*-
 *-----------------------------------------------------------------------
 * SuffFree  --
 *	Free up all memory associated with the given suffix structure.
 *
 * Results:
 *	none
 *
 * Side Effects:
 *	the suffix entry is detroyed
 *-----------------------------------------------------------------------
 */
static void
SuffFree(void *sp)
{
	Suff *s = sp;

	if (s == suffNull)
		suffNull = NULL;

	if (s == emptySuff)
		emptySuff = NULL;

	Lst_Destroy(&s->ref, NOFREE);
	Lst_Destroy(&s->children, NOFREE);
	Lst_Destroy(&s->parents, NOFREE);
	Lst_Destroy(&s->searchPath, Dir_Destroy);

	free(s->name);
	free(s);
}
#endif

/*-
 *-----------------------------------------------------------------------
 * SuffRemove  --
 *	Remove the suffix into the list
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	The reference count for the suffix is decremented
 *-----------------------------------------------------------------------
 */
static void
SuffRemove(Lst *l, Suff *s)
{
	LstNode	*ln = Lst_Member(l, s);

	if (ln != NULL) {
		Lst_Remove(l, ln);
		s->refCount--;
	}
}

/*-
 *-----------------------------------------------------------------------
 * SuffInsert  --
 *	Insert the suffix into the list keeping the list ordered by suffix
 *	numbers.
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	The reference count of the suffix is incremented
 *-----------------------------------------------------------------------
 */
static void
SuffInsert(Lst *l, Suff *s)
{
	LstNode	*ln;	/* current element in l we're examining */
	Suff	*s2;	/* the suffix descriptor in this element */

	s2 = NULL;
	for (ln = Lst_First(l); ln != NULL; ln = Lst_Succ(ln)) {
		s2 = Lst_Datum(ln);
		if (s2->sNum >= s->sNum)
			break;
	}
	if (s2 == NULL) {
		DEBUGF(SUFF, ("inserting an empty list?..."));
	}

	DEBUGF(SUFF, ("inserting %s(%d)...", s->name, s->sNum));
	if (ln == NULL) {
		DEBUGF(SUFF, ("at end of list\n"));
		Lst_AtEnd(l, s);
		s->refCount++;
		Lst_AtEnd(&s->ref, l);
	} else if (s2->sNum != s->sNum) {
		DEBUGF(SUFF, ("before %s(%d)\n", s2->name, s2->sNum));
		Lst_Insert(l, ln, s);
		s->refCount++;
		Lst_AtEnd(&s->ref, l);
	} else {
		DEBUGF(SUFF, ("already there\n"));
	}
}

/*-
 *-----------------------------------------------------------------------
 * Suff_ClearSuffixes --
 *	This is gross. Nuke the list of suffixes but keep all transformation
 *	rules around. The transformation graph is destroyed in this process,
 *	but we leave the list of rules so when a new graph is formed the rules
 *	will remain.
 *	This function is called from the parse module when a
 *	.SUFFIXES:\n line is encountered.
 *
 * Results:
 *	none
 *
 * Side Effects:
 *	the sufflist and its graph nodes are destroyed
 *-----------------------------------------------------------------------
 */
void
Suff_ClearSuffixes(void)
{

	Lst_Concat(&suffClean, &sufflist, LST_CONCLINK);

	sNum = 1;
	suffNull = emptySuff;
	/*
	 * Clear suffNull's children list (the other suffixes are built new, but
	 * suffNull is used as is).
	 * NOFREE is used because all suffixes are are on the suffClean list.
	 * suffNull should not have parents.
	 */
	Lst_Destroy(&suffNull->children, NOFREE);
}

/*-
 *-----------------------------------------------------------------------
 * SuffParseTransform --
 *	Parse a transformation string to find its two component suffixes.
 *
 * Results:
 *	TRUE if the string is a valid transformation and FALSE otherwise.
 *
 * Side Effects:
 *	The passed pointers are overwritten.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
SuffParseTransform(char *str, Suff **srcPtr, Suff **targPtr)
{
	LstNode	*srcLn;		/* element in suffix list of trans source*/
	Suff	*src;		/* Source of transformation */
	char	*str2;		/* Extra pointer (maybe target suffix) */
	LstNode	*singleLn;	/* element in suffix list of any suffix
				 * that exactly matches str */
	Suff	*single = NULL;	/* Source of possible transformation to
				 * null suffix */

	singleLn = NULL;

	/*
	 * Loop looking first for a suffix that matches the start of the
	 * string and then for one that exactly matches the rest of it. If
	 * we can find two that meet these criteria, we've successfully
	 * parsed the string.
	 */
	srcLn = Lst_First(&sufflist);
	for (;;) {
		/* advance to next possible suffix */
		while (srcLn != NULL) {
			src = Lst_Datum(srcLn);
			if (strncmp(str, src->name, strlen(src->name)) == 0)
				break;
			srcLn = LST_NEXT(srcLn);
		}

		if (srcLn == NULL) {
			/*
			 * Ran out of source suffixes -- no such rule
			 */
			if (singleLn != NULL) {
				/*
				 * Not so fast Mr. Smith! There was a suffix
				 * that encompassed the entire string, so we
				 * assume it was a transformation to the null
				 * suffix (thank you POSIX). We still prefer to
				 * find a double rule over a singleton, hence we
				 * leave this check until the end.
				 *
				 * XXX: Use emptySuff over suffNull?
				 */
				*srcPtr = single;
				*targPtr = suffNull;
				return (TRUE);
			}
			return (FALSE);
		}
		str2 = str + src->nameLen;
		if (*str2 == '\0') {
			single = src;
			singleLn = srcLn;
		} else {

			*targPtr = SuffSuffFind(str2);
			if (*targPtr != NULL) {
				*srcPtr = src;
				return (TRUE);
			}
		}
		/* next one */
		srcLn = LST_NEXT(srcLn);
	}
}

/*-
 *-----------------------------------------------------------------------
 * Suff_IsTransform  --
 *	Return TRUE if the given string is a transformation rule
 *
 *
 * Results:
 *	TRUE if the string is a concatenation of two known suffixes.
 *	FALSE otherwise
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
Boolean
Suff_IsTransform(char *str)
{
	Suff	*src, *targ;

	return (SuffParseTransform(str, &src, &targ));
}

/*-
 *-----------------------------------------------------------------------
 * Suff_AddTransform --
 *	Add the transformation rule described by the line to the
 *	list of rules and place the transformation itself in the graph
 *
 * Results:
 *	The node created for the transformation in the transforms list
 *
 * Side Effects:
 *	The node is placed on the end of the transforms Lst and links are
 *	made between the two suffixes mentioned in the target name
 *-----------------------------------------------------------------------
 */
GNode *
Suff_AddTransform(char *line)
{
	GNode	*gn;	/* GNode of transformation rule */
	Suff	*s;	/* source suffix */
	Suff	*t;	/* target suffix */

	s = t = NULL;	/* silence gcc */
	gn = SuffTransFind(line);
	if (gn == NULL) {
		/*
		 * Make a new graph node for the transformation.
		 * It will be filled in by the Parse module.
		 */
		gn = Targ_NewGN(line);
		Lst_AtEnd(&transforms, gn);
	} else {
		/*
		 * New specification for transformation rule. Just nuke the
		 * old list of commands so they can be filled in again...
		 * We don't actually free the commands themselves, because a
		 * given command can be attached to several different
		 * transformations.
		 */
		Lst_Destroy(&gn->commands, NOFREE);
		Lst_Destroy(&gn->children, NOFREE);
	}

	gn->type = OP_TRANSFORM;

	SuffParseTransform(line, &s, &t);

	/*
	 * link the two together in the proper relationship and order
	 */
	DEBUGF(SUFF, ("defining transformation from `%s' to `%s'\n",
	    s->name, t->name));
	SuffInsert(&t->children, s);
	SuffInsert(&s->parents, t);

	return (gn);
}

/*-
 *-----------------------------------------------------------------------
 * Suff_EndTransform --
 *	Handle the finish of a transformation definition, removing the
 *	transformation from the graph if it has neither commands nor
 *	sources. This is called from the Parse module at the end of
 *	a dependency block.
 *
 * Side Effects:
 *	If the node has no commands or children, the children and parents
 *	lists of the affected suffices are altered.
 *
 *-----------------------------------------------------------------------
 */
void
Suff_EndTransform(const GNode *gn)
{
	Suff	*s, *t;

	if (!Lst_IsEmpty(&gn->commands) || !Lst_IsEmpty(&gn->children)) {
		DEBUGF(SUFF, ("transformation %s complete\n", gn->name));
		return;
	}

	/*
	 * SuffParseTransform() may fail for special rules which are not
	 * actual transformation rules (e.g., .DEFAULT).
	 */
	if (!SuffParseTransform(gn->name, &s, &t))
		return;

	DEBUGF(SUFF, ("deleting transformation from `%s' to `%s'\n",
	    s->name, t->name));

	/*
	 * Remove the source from the target's children list. We check
	 * for a NULL return to handle a beanhead saying something like
	 *  .c.o .c.o:
	 *
	 * We'll be called twice when the next target is seen, but .c
	 * and .o are only linked once...
	 */
	SuffRemove(&t->children, s);

	/*
	 * Remove the target from the source's parents list
	 */
	SuffRemove(&s->parents, t);
}

/*-
 *-----------------------------------------------------------------------
 * SuffRebuildGraph --
 *	Called from Suff_AddSuffix via LST_FOREACH to search through the
 *	list of existing transformation rules and rebuild the transformation
 *	graph when it has been destroyed by Suff_ClearSuffixes. If the
 *	given rule is a transformation involving this suffix and another,
 *	existing suffix, the proper relationship is established between
 *	the two.
 *
 * Side Effects:
 *	The appropriate links will be made between this suffix and
 *	others if transformation rules exist for it.
 *
 *-----------------------------------------------------------------------
 */
static void
SuffRebuildGraph(const GNode *transform, Suff *s)
{
	char	*cp;
	Suff	*s2 = NULL;

	/*
	 * First see if it is a transformation from this suffix.
	 */
	if (strncmp(transform->name, s->name, strlen(s->name)) == 0) {
		cp = transform->name + strlen(s->name);

		if (cp[0] == '\0')  /* null rule */
			s2 = suffNull;
		else
			s2 = SuffSuffFind(cp);
		if (s2 != NULL) {
			/*
			 * Found target. Link in and return, since it can't be
			 * anything else.
			 */
			SuffInsert(&s2->children, s);
			SuffInsert(&s->parents, s2);
			return;
		}
	}

	/*
	 * Not from, maybe to?
	 */
	cp = SuffSuffIsSuffix(s, transform->name);
	if (cp != NULL) {
		/*
		 * Null-terminate the source suffix in order to find it.
		 */
		cp[1] = '\0';
		s2 = SuffSuffFind(transform->name);

		/*
		 * Replace the start of the target suffix
		 */
		cp[1] = s->name[0];
		if (s2 != NULL) {
			/*
			 * Found it -- establish the proper relationship
			 */
			SuffInsert(&s->children, s2);
			SuffInsert(&s2->parents, s);
		}
	}
}

/*-
 *-----------------------------------------------------------------------
 * Suff_AddSuffix --
 *	Add the suffix in string to the end of the list of known suffixes.
 *	Should we restructure the suffix graph? Make doesn't...
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	A GNode is created for the suffix and a Suff structure is created and
 *	added to the suffixes list unless the suffix was already known.
 *-----------------------------------------------------------------------
 */
void
Suff_AddSuffix(char *str)
{
	Suff	*s;	/* new suffix descriptor */
	LstNode	*ln;

	if (SuffSuffFind(str) != NULL)
		/*
		 * Already known
		 */
		return;

	s = emalloc(sizeof(Suff));

	s->name = estrdup(str);
	s->nameLen = strlen(s->name);
	TAILQ_INIT(&s->searchPath);
	Lst_Init(&s->children);
	Lst_Init(&s->parents);
	Lst_Init(&s->ref);
	s->sNum = sNum++;
	s->flags = 0;
	s->refCount = 0;

	Lst_AtEnd(&sufflist, s);

	/*
	 * Look for any existing transformations from or to this suffix.
	 * XXX: Only do this after a Suff_ClearSuffixes?
	 */
	LST_FOREACH(ln, &transforms)
		SuffRebuildGraph(Lst_Datum(ln), s);
}

/*-
 *-----------------------------------------------------------------------
 * Suff_GetPath --
 *	Return the search path for the given suffix, if it's defined.
 *
 * Results:
 *	The searchPath for the desired suffix or NULL if the suffix isn't
 *	defined.
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
struct Path *
Suff_GetPath(char *sname)
{
	Suff	*s;

	s = SuffSuffFind(sname);
	if (s == NULL)
		return (NULL);
	return (&s->searchPath);
}

/*-
 *-----------------------------------------------------------------------
 * Suff_DoPaths --
 *	Extend the search paths for all suffixes to include the default
 *	search path.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The searchPath field of all the suffixes is extended by the
 *	directories in dirSearchPath. If paths were specified for the
 *	".h" suffix, the directories are stuffed into a global variable
 *	called ".INCLUDES" with each directory preceded by a -I. The same
 *	is done for the ".a" suffix, except the variable is called
 *	".LIBS" and the flag is -L.
 *-----------------------------------------------------------------------
 */
void
Suff_DoPaths(void)
{
	Suff	*s;
	LstNode	*ln;
	char	*ptr;
	struct Path inIncludes;	/* Cumulative .INCLUDES path */
	struct Path inLibs;	/* Cumulative .LIBS path */

	TAILQ_INIT(&inIncludes);
	TAILQ_INIT(&inLibs);

	for (ln = Lst_First(&sufflist); ln != NULL; ln = Lst_Succ(ln)) {
		s = Lst_Datum(ln);
#ifdef INCLUDES
		if (s->flags & SUFF_INCLUDE) {
			Path_Concat(&inIncludes, &s->searchPath);
		}
#endif /* INCLUDES */
#ifdef LIBRARIES
		if (s->flags & SUFF_LIBRARY) {
			Path_Concat(&inLibs, &s->searchPath);
		}
#endif /* LIBRARIES */
		Path_Concat(&s->searchPath, &dirSearchPath);
	}

	ptr = Path_MakeFlags("-I", &inIncludes);
	Var_SetGlobal(".INCLUDES", ptr);
	free(ptr);

	ptr = Path_MakeFlags("-L", &inLibs);
	Var_SetGlobal(".LIBS", ptr);
	free(ptr);

	Path_Clear(&inIncludes);
	Path_Clear(&inLibs);
}

/*-
 *-----------------------------------------------------------------------
 * Suff_AddInclude --
 *	Add the given suffix as a type of file which gets included.
 *	Called from the parse module when a .INCLUDES line is parsed.
 *	The suffix must have already been defined.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The SUFF_INCLUDE bit is set in the suffix's flags field
 *
 *-----------------------------------------------------------------------
 */
void
Suff_AddInclude(char *sname)
{
	Suff	*s;

	if ((s = SuffSuffFind(sname)) != NULL)
		s->flags |= SUFF_INCLUDE;
}

/*-
 *-----------------------------------------------------------------------
 * Suff_AddLib --
 *	Add the given suffix as a type of file which is a library.
 *	Called from the parse module when parsing a .LIBS line. The
 *	suffix must have been defined via .SUFFIXES before this is
 *	called.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The SUFF_LIBRARY bit is set in the suffix's flags field
 *
 *-----------------------------------------------------------------------
 */
void
Suff_AddLib(char *sname)
{
	Suff	*s;

	if ((s = SuffSuffFind(sname)) != NULL)
		s->flags |= SUFF_LIBRARY;
}

/*
 * Create a new Src structure
 */
static Src *
SuffSrcCreate(char *file, char *prefix, Suff *suff, Src *parent, GNode *node)
{
	Src	*s;

	s = emalloc(sizeof(*s));
	s->file = file;
	s->pref = prefix;
	s->suff = suff;
	s->parent = parent;
	s->node = node;
	s->children = 0;

#ifdef DEBUG_SRC
	Lst_Init(&s->cp);
#endif

	return (s);
}

 	  /********** Implicit Source Search Functions *********/

/*-
 *-----------------------------------------------------------------------
 * SuffAddLevel  --
 *	Add all the children of targ as Src structures to the given list:
 *	Add a suffix as a Src structure to the given list with its parent
 *	being the given Src structure. If the suffix is the null suffix,
 *	the prefix is used unaltered as the file name in the Src structure.
 *
 * Results:
 *	None
 *
 * Side Effects:
 * 	Lots of structures are created and added to the list
 *-----------------------------------------------------------------------
 */
static void
SuffAddLevel(Lst *l, Src *targ)
{
	LstNode		*ln;
	Suff		*suff;
	Src		*s2;
#ifdef DEBUG_SRC
	const LstNode	*ln1;
#endif

	LST_FOREACH(ln, &targ->suff->children) {
		suff = Lst_Datum(ln);

		if ((suff->flags & SUFF_NULL) && *suff->name != '\0') {
			/*
			 * If the suffix has been marked as the NULL suffix,
			 * also create a Src structure for a file with no suffix
			 * attached. Two birds, and all that...
			 */
			s2 = SuffSrcCreate(estrdup(targ->pref), targ->pref,
			    suff, targ, NULL);
			suff->refCount++;
			targ->children += 1;
			Lst_AtEnd(l, s2);
#ifdef DEBUG_SRC
			Lst_AtEnd(&targ->cp, s2);
			printf("1 add %p %p to %p:", targ, s2, l);
			LST_FOREACH(ln1, l)
				printf("%p ", (const void *)Lst_Datum(ln1));
			printf("\n");
#endif
		}
		s2 = SuffSrcCreate(str_concat(targ->pref, suff->name, 0),
		    targ->pref, suff, targ, NULL);
		suff->refCount++;
		targ->children += 1;
		Lst_AtEnd(l, s2);
#ifdef DEBUG_SRC
		Lst_AtEnd(&targ->cp, s2);
		printf("2 add %p %p to %p:", targ, s2, l);
		LST_FOREACH(ln1, l)
			printf("%p ", (const void *)Lst_Datum(ln1));
		printf("\n");
#endif
	}
}

/*-
 *----------------------------------------------------------------------
 * SuffRemoveSrc --
 *	Free all src structures in list that don't have a reference count
 *	XXX this actually frees only the first of these.
 *
 * Results:
 *	True if a src was removed
 *
 * Side Effects:
 *	The memory is free'd.
 *----------------------------------------------------------------------
 */
static int
SuffRemoveSrc(Lst *l)
{
	LstNode	*ln, *ln1;
	Src	*s;
	int	t = 0;

#ifdef DEBUG_SRC
	printf("cleaning %lx: ", (unsigned long) l);
	LST_FOREACH(ln, l)
		printf("%p ", (const void *)Lst_Datum(ln));
	printf("\n");
#endif

	for (ln = Lst_First(l); ln != NULL; ln = ln1) {
		ln1 = Lst_Succ(ln);

		s = (Src *)Lst_Datum(ln);
		if (s->children == 0) {
			free(s->file);
			if (!s->parent)
				free(s->pref);
			else {
#ifdef DEBUG_SRC
				LstNode *ln = Lst_Member(&s->parent->cp, s);
				if (ln != NULL)
					Lst_Remove(&s->parent->cp, ln);
#endif
				--s->parent->children;
			}
#ifdef DEBUG_SRC
			printf("free: [l=%p] p=%p %d\n", l, s, s->children);
			Lst_Destroy(&s->cp, NOFREE);
#endif
			Lst_Remove(l, ln);
			free(s);
			t |= 1;
			return (TRUE);
		}
#ifdef DEBUG_SRC
		else {
			const LstNode *tln;

			printf("keep: [l=%p] p=%p %d: ", l, s, s->children);
			LST_FOREACH(tln, &s->cp)
				printf("%p ", (const void *)Lst_Datum(tln));
			printf("\n");
		}
#endif
	}

	return (t);
}

/*-
 *-----------------------------------------------------------------------
 * SuffFindThem --
 *	Find the first existing file/target in the list srcs
 *
 * Results:
 *	The lowest structure in the chain of transformations
 *
 * Side Effects:
 *	None
 *-----------------------------------------------------------------------
 */
static Src *
SuffFindThem(Lst *srcs, Lst *slst)
{
	Src	*s;	/* current Src */
	Src	*rs;	/* returned Src */
	char	*ptr;

	rs = NULL;

	while (!Lst_IsEmpty (srcs)) {
		s = Lst_DeQueue(srcs);

		DEBUGF(SUFF, ("\ttrying %s...", s->file));

		/*
		 * A file is considered to exist if either a node exists in the
		 * graph for it or the file actually exists.
		 */
		if (Targ_FindNode(s->file, TARG_NOCREATE) != NULL) {
#ifdef DEBUG_SRC
			printf("remove %p from %p\n", s, srcs);
#endif
			rs = s;
			break;
		}

		if ((ptr = Path_FindFile(s->file,
		    &s->suff->searchPath)) != NULL) {
			rs = s;
#ifdef DEBUG_SRC
			printf("remove %p from %p\n", s, srcs);
#endif
			free(ptr);
			break;
		}

		DEBUGF(SUFF, ("not there\n"));

		SuffAddLevel(srcs, s);
		Lst_AtEnd(slst, s);
	}

	if (rs) {
		DEBUGF(SUFF, ("got it\n"));
	}
	return (rs);
}

/*-
 *-----------------------------------------------------------------------
 * SuffFindCmds --
 *	See if any of the children of the target in the Src structure is
 *	one from which the target can be transformed. If there is one,
 *	a Src structure is put together for it and returned.
 *
 * Results:
 *	The Src structure of the "winning" child, or NULL if no such beast.
 *
 * Side Effects:
 *	A Src structure may be allocated.
 *
 *-----------------------------------------------------------------------
 */
static Src *
SuffFindCmds(Src *targ, Lst *slst)
{
	LstNode	*ln;	/* General-purpose list node */
	GNode	*t;	/* Target GNode */
	GNode	*s;	/* Source GNode */
	int	prefLen;/* The length of the defined prefix */
	Suff	*suff;	/* Suffix on matching beastie */
	Src	*ret;	/* Return value */
	char	*cp;

	t = targ->node;
	prefLen = strlen(targ->pref);

	for (ln = Lst_First(&t->children); ln != NULL; ln = Lst_Succ(ln)) {
		s = Lst_Datum(ln);

		cp = strrchr(s->name, '/');
		if (cp == NULL) {
			cp = s->name;
		} else {
			cp++;
		}
		if (strncmp(cp, targ->pref, prefLen) == 0) {
			/*
			 * The node matches the prefix ok, see if it has
			 * a known suffix.
			 */
			suff = SuffSuffFind(&cp[prefLen]);
			if (suff != NULL) {
				/*
				 * It even has a known suffix, see if there's
				 * a transformation defined between the node's
				 * suffix and the target's suffix.
				 *
				 * XXX: Handle multi-stage transformations
				 * here, too.
				 */
				if (Lst_Member(&suff->parents,
				    targ->suff) != NULL) {
					/*
					 * Hot Damn! Create a new Src structure
					 * to describe this transformation
					 * (making sure to duplicate the
					 * source node's name so Suff_FindDeps
					 * can free it again (ick)), and return
					 * the new structure.
					 */
					ret = SuffSrcCreate(estrdup(s->name),
					    targ->pref, suff, targ, s);
					suff->refCount++;
					targ->children += 1;
#ifdef DEBUG_SRC
					printf("3 add %p %p\n", &targ, ret);
					Lst_AtEnd(&targ->cp, ret);
#endif
					Lst_AtEnd(slst, ret);
					DEBUGF(SUFF, ("\tusing existing source "
					    "%s\n", s->name));
					return (ret);
				}
			}
		}
	}
	return (NULL);
}

/*-
 * The child node contains variable references. Expand them and return
 * a list of expansions.
 */
static void
SuffExpandVariables(GNode *parent, GNode *child, Lst *members)
{
	Buffer	*buf;
	char	*cp;
	char	*start;

	Lst_Init(members);

	DEBUGF(SUFF, ("Expanding \"%s\"...", child->name));
	buf = Var_Subst(child->name, parent, TRUE);
	cp = Buf_Data(buf);

	if (child->type & OP_ARCHV) {
		/*
		 * Node was an archive(member) target, so we
		 * want to call on the Arch module to find the
		 * nodes for us, expanding variables in the
		 * parent's context.
		 */
		Arch_ParseArchive(&cp, members, parent);
		Buf_Destroy(buf, TRUE);
		return;
	}
	/*
	 * Break the result into a vector of strings whose nodes we can find,
	 * then add those nodes to the members list. Unfortunately, we can't use
	 * brk_string b/c it doesn't understand about variable specifications
	 * with spaces in them... XXX
	 */
	for (start = cp; *start == ' ' || *start == '\t'; start++)
		;

	for (cp = start; *cp != '\0'; cp++) {
		if (*cp == ' ' || *cp == '\t') {
			/*
			 * White-space -- terminate element, find the node,
			 * add it, skip any further spaces.
			 */
			*cp++ = '\0';
			Lst_AtEnd(members, Targ_FindNode(start, TARG_CREATE));

			while (*cp == ' ' || *cp == '\t') {
				cp++;
			}
			/*
			 * Adjust cp for increment at
			 * start of loop, but set start
			 * to first non-space.
			 */
			start = cp--;

		} else if (*cp == '$') {
			/*
			 * Start of a variable spec -- contact variable module
			 * to find the end so we can skip over it.
			 */
			char	*junk;
			size_t	len = 0;
			Boolean	doFree;

			junk = Var_Parse(cp, parent, TRUE, &len, &doFree);
			if (junk != var_Error) {
				cp += len - 1;
			}
			if (doFree) {
				free(junk);
			}

		} else if (*cp == '\\' && *cp != '\0') {
			/*
			 * Escaped something -- skip over it
			 */
			cp++;
		}
	}

	if (cp != start) {
		/*
		 * Stuff left over -- add it to the
		 * list too
		 */
		Lst_AtEnd(members, Targ_FindNode(start, TARG_CREATE));
	}

	Buf_Destroy(buf, TRUE);
}

/*-
 * The child node contains wildcards. Expand them and return a list of
 * expansions.
 */
static void
SuffExpandWildcards(GNode *child, Lst *members)
{
	char	*cp;
	Lst	exp;	/* List of expansions */
	LstNode	*ln;
	struct Path *path;	/* Search path along which to expand */

	Lst_Init(members);

	/*
	 * Find a path along which to expand the word.
	 *
	 * If the word has a known suffix, use that path.
	 * If it has no known suffix and we're allowed to use the null
	 *   suffix, use its path.
	 * Else use the default system search path.
	 */
	LST_FOREACH(ln, &sufflist) {
		if (SuffSuffIsSuffix(Lst_Datum(ln), child->name) != NULL)
			break;
	}

	DEBUGF(SUFF, ("Wildcard expanding \"%s\"...", child->name));

	if (ln != NULL) {
		Suff	*s = Lst_Datum(ln);

		DEBUGF(SUFF, ("suffix is \"%s\"...", s->name));
		path = &s->searchPath;
	} else {
		/*
		 * Use default search path
		 */
		path = &dirSearchPath;
	}

	/*
	 * Expand the word along the chosen path
	 */
	Lst_Init(&exp);
	Path_Expand(child->name, path, &exp);

	while (!Lst_IsEmpty(&exp)) {
		/*
		 * Fetch next expansion off the list and find its GNode
		 */
		cp = Lst_DeQueue(&exp);

		DEBUGF(SUFF, ("%s...", cp));
		Lst_AtEnd(members, Targ_FindNode(cp, TARG_CREATE));
	}
}

/*-
 *-----------------------------------------------------------------------
 * SuffExpandChildren --
 *	Expand the names of any children of a given node that contain
 *	variable invocations or file wildcards into actual targets.
 *
 * Results:
 *	== 0 (continue)
 *
 * Side Effects:
 *	The expanded node is removed from the parent's list of children,
 *	and the parent's unmade counter is decremented, but other nodes
 * 	may be added.
 *
 *-----------------------------------------------------------------------
 */
static void
SuffExpandChildren(GNode *parent, LstNode *current)
{
	GNode	*cchild;	/* current child */
	GNode	*gn;
	LstNode	*prev;		/* node after which to append new source */
	Lst	members;	/* expanded nodes */

	if (current == NULL) {
		/* start from begin of parent's children list */
		current = Lst_First(&parent->children);
	}

	while (current != NULL) {
		cchild = Lst_Datum(current);

		/*
		 * First do variable expansion -- this takes precedence over
		 * wildcard expansion. If the result contains wildcards, they'll
		 * be gotten to later since the resulting words are tacked
		 * instead of the current child onto the children list.
		 *
		 * XXXHB what if cchild contains lib.a(t1.o t2.o t3.o) but
		 * no $?
		 */
		if (strchr(cchild->name, '$') != NULL) {
			SuffExpandVariables(parent, cchild, &members);

		} else if (Dir_HasWildcards(cchild->name)) {
			SuffExpandWildcards(cchild, &members);

		} else {
			/* nothing special just advance to next child */
			current = LST_NEXT(current);
			continue;
		}

		/*
		 * New nodes effectively take the place of the child,
		 * so place them after the child
		 */
		prev = current;

		/*
		 * Add all new elements to the parent node if they aren't
		 * already children of it.
		 */
		while(!Lst_IsEmpty(&members)) {
			gn = Lst_DeQueue(&members);

			DEBUGF(SUFF, ("%s...", gn->name));
			if (Lst_Member(&parent->children, gn) == NULL) {
				Lst_Append(&parent->children, prev, gn);
				prev = Lst_Succ(prev);
				Lst_AtEnd(&gn->parents, parent);
				parent->unmade++;
			}
		}

		/*
		 * Now the source is expanded, remove it from the list
		 * of children to keep it from being processed.
		 * Advance to the next child.
		 */
		prev = current;
		current = LST_NEXT(current);

		parent->unmade--;
		Lst_Remove(&parent->children, prev);
		DEBUGF(SUFF, ("\n"));
	}
}

/*-
 *-----------------------------------------------------------------------
 * SuffApplyTransform --
 *	Apply a transformation rule, given the source and target nodes
 *	and suffixes.
 *
 * Results:
 *	TRUE if successful, FALSE if not.
 *
 * Side Effects:
 *	The source and target are linked and the commands from the
 *	transformation are added to the target node's commands list.
 *	All attributes but OP_DEPMASK and OP_TRANSFORM are applied
 *	to the target. The target also inherits all the sources for
 *	the transformation rule.
 *
 *-----------------------------------------------------------------------
 */
static Boolean
SuffApplyTransform(GNode *tGn, GNode *sGn, Suff *t, Suff *s)
{
	LstNode	*ln;	/* General node */
	char	*tname;	/* Name of transformation rule */
	GNode	*gn;	/* Node for same */

	if (Lst_Member(&tGn->children, sGn) == NULL) {
		/*
		 * Not already linked, so form the proper links between the
		 * target and source.
		 */
		Lst_AtEnd(&tGn->children, sGn);
		Lst_AtEnd(&sGn->parents, tGn);
		tGn->unmade += 1;
	}

	if ((sGn->type & OP_OPMASK) == OP_DOUBLEDEP) {
		/*
		 * When a :: node is used as the implied source of a node,
		 * we have to link all its cohorts in as sources as well. Only
		 * the initial sGn gets the target in its iParents list, however
		 * as that will be sufficient to get the .IMPSRC variable set
		 * for tGn
		 */
		for (ln = Lst_First(&sGn->cohorts); ln != NULL;
		    ln = Lst_Succ(ln)) {
			gn = Lst_Datum(ln);

			if (Lst_Member(&tGn->children, gn) == NULL) {
				/*
				 * Not already linked, so form the proper
				 * links between the target and source.
				 */
				Lst_AtEnd(&tGn->children, gn);
				Lst_AtEnd(&gn->parents, tGn);
				tGn->unmade += 1;
			}
		}
	}
	/*
	 * Locate the transformation rule itself
	 */
	tname = str_concat(s->name, t->name, 0);
	gn = SuffTransFind(tname);
	free(tname);

	if (gn == NULL) {
		/*
		 * Not really such a transformation rule (can happen when we're
		 * called to link an OP_MEMBER and OP_ARCHV node), so return
		 * FALSE.
		 */
		return (FALSE);
	}

	DEBUGF(SUFF, ("\tapplying %s -> %s to \"%s\"\n",
	    s->name, t->name, tGn->name));

	/*
	 * Record last child for expansion purposes
	 */
	ln = Lst_Last(&tGn->children);

	/*
	 * Pass the buck to Make_HandleUse to apply the rule
	 */
	Make_HandleUse(gn, tGn);

	/*
	 * Deal with wildcards and variables in any acquired sources
	 */
	ln = Lst_Succ(ln);
	if (ln != NULL) {
		SuffExpandChildren(tGn, ln);
	}

	/*
	 * Keep track of another parent to which this beast is transformed so
	 * the .IMPSRC variable can be set correctly for the parent.
	 */
	Lst_AtEnd(&sGn->iParents, tGn);

	return (TRUE);
}


/*-
 *-----------------------------------------------------------------------
 * SuffFindArchiveDeps --
 *	Locate dependencies for an OP_ARCHV node.
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	Same as Suff_FindDeps
 *
 *-----------------------------------------------------------------------
 */
static void
SuffFindArchiveDeps(GNode *gn, Lst *slst)
{
	char	*eoarch;	/* End of archive portion */
	char	*eoname;	/* End of member portion */
	char	*name;		/* Start of member's name */
	GNode	*mem;		/* Node for member */
	Suff	*ms;		/* Suffix descriptor for member */

	static const char *copy[] = {
		TARGET,		/* Must be first */
		PREFIX,		/* Must be second */
	};

	/*
	 * The node is an archive(member) pair. so we must find a
	 * suffix for both of them.
	 */
	eoarch = strchr(gn->name, '(');
	eoname = strchr(eoarch, ')');

	*eoname = '\0';	  /* Nuke parentheses during suffix search */
	*eoarch = '\0';	  /* So a suffix can be found */

	name = eoarch + 1;

	/*
	 * To simplify things, call Suff_FindDeps recursively on the member now,
	 * so we can simply compare the member's .PREFIX and .TARGET variables
	 * to locate its suffix. This allows us to figure out the suffix to
	 * use for the archive without having to do a quadratic search over the
	 * suffix list, backtracking for each one...
	 */
	mem = Targ_FindNode(name, TARG_CREATE);
	SuffFindDeps(mem, slst);

	/*
	 * Create the link between the two nodes right off
	 */
	if (Lst_Member(&gn->children, mem) == NULL) {
		Lst_AtEnd(&gn->children, mem);
		Lst_AtEnd(&mem->parents, gn);
		gn->unmade += 1;
	}

	/*
	 * Copy in the variables from the member node to this one.
	 */
	Var_Set(copy[1], Var_Value(copy[1], mem), gn);
	Var_Set(copy[0], Var_Value(copy[0], mem), gn);

	ms = mem->suffix;
	if (ms == NULL) {
		/*
		 * Didn't know what it was -- use .NULL suffix if not in
		 * make mode
		 */
		DEBUGF(SUFF, ("using null suffix\n"));
		ms = suffNull;
	}

	/*
	* Set the other two local variables required for this target.
	*/
	Var_Set(MEMBER, name, gn);
	Var_Set(ARCHIVE, gn->name, gn);

	if (ms != NULL) {
		/*
		 * Member has a known suffix, so look for a transformation rule
		 * from it to a possible suffix of the archive. Rather than
		 * searching through the entire list, we just look at suffixes
		 * to which the member's suffix may be transformed...
		 */
		LstNode *ln;

		/*
		 * Use first matching suffix...
		 */
		LST_FOREACH(ln, &ms->parents) {
			if (SuffSuffIsSuffix(Lst_Datum(ln), gn->name) != NULL)
				break;
		}

		if (ln != NULL) {
			/*
			 * Got one -- apply it
			 */
			if (!SuffApplyTransform(gn, mem, Lst_Datum(ln), ms)) {
				DEBUGF(SUFF, ("\tNo transformation from "
				    "%s -> %s\n", ms->name,
				    ((Suff *)Lst_Datum(ln))->name));
			}
		}
	}

	/*
	 * Replace the opening and closing parens now we've no need
	 * of the separate pieces.
	 */
	*eoarch = '(';
	*eoname = ')';

	/*
	 * Pretend gn appeared to the left of a dependency operator so
	 * the user needn't provide a transformation from the member to the
	 * archive.
	 */
	if (OP_NOP(gn->type)) {
		gn->type |= OP_DEPENDS;
	}

	/*
	 * Flag the member as such so we remember to look in the archive for
	 * its modification time.
	 */
	mem->type |= OP_MEMBER;
}

/*-
 *-----------------------------------------------------------------------
 * SuffFindNormalDeps --
 *	Locate implicit dependencies for regular targets.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	Same as Suff_FindDeps...
 *
 *-----------------------------------------------------------------------
 */
static void
SuffFindNormalDeps(GNode *gn, Lst *slst)
{
	char	*eoname;	/* End of name */
	char	*sopref;	/* Start of prefix */
	LstNode	*ln;		/* Next suffix node to check */
	Lst	srcs;		/* List of sources at which to look */
	Lst	targs;		/* List of targets to which things can be
				 * transformed. They all have the same file,
				 * but different suff and pref fields */
	Src	*bottom;	/* Start of found transformation path */
	Src	*src;		/* General Src pointer */
	char	*pref;		/* Prefix to use */
	Src	*targ;		/* General Src target pointer */

	eoname = gn->name + strlen(gn->name);
	sopref = gn->name;

	/*
	 * Begin at the beginning...
	 */
	ln = Lst_First(&sufflist);
	Lst_Init(&srcs);
	Lst_Init(&targs);

	/*
	 * We're caught in a catch-22 here. On the one hand, we want to use any
	 * transformation implied by the target's sources, but we can't examine
	 * the sources until we've expanded any variables/wildcards they may
	 * hold, and we can't do that until we've set up the target's local
	 * variables and we can't do that until we know what the proper suffix
	 * for the target is (in case there are two suffixes one of which is a
	 * suffix of the other) and we can't know that until we've found its
	 * implied source, which we may not want to use if there's an existing
	 * source that implies a different transformation.
	 *
	 * In an attempt to get around this, which may not work all the time,
	 * but should work most of the time, we look for implied sources first,
	 * checking transformations to all possible suffixes of the target,
	 * use what we find to set the target's local variables, expand the
	 * children, then look for any overriding transformations they imply.
	 * Should we find one, we discard the one we found before.
	 */

	while (ln != NULL) {
		/*
		 * Look for next possible suffix...
		 */
		while (ln != NULL) {
			if (SuffSuffIsSuffix(Lst_Datum(ln), gn->name) != NULL)
				break;
			ln = LST_NEXT(ln);
		}
				
		if (ln != NULL) {
			int	prefLen;	/* Length of the prefix */
			Src	*target;

			/*
			 * Allocate a Src structure to which things can be
			 * transformed
			 */
			target = SuffSrcCreate(estrdup(gn->name), NULL,
			    Lst_Datum(ln), NULL, gn);
			target->suff->refCount++;

			/*
			 * Allocate room for the prefix, whose end is found
			 * by subtracting the length of the suffix from
			 * the end of the name.
			 */
			prefLen = (eoname - target->suff->nameLen) - sopref;
			assert(prefLen >= 0);
			target->pref = emalloc(prefLen + 1);
			memcpy(target->pref, sopref, prefLen);
			target->pref[prefLen] = '\0';

			/*
			 * Add nodes from which the target can be made
			 */
			SuffAddLevel(&srcs, target);

			/*
			 * Record the target so we can nuke it
			 */
			Lst_AtEnd(&targs, target);

			/*
			 * Search from this suffix's successor...
			 */
			ln = Lst_Succ(ln);
		}
	}

	/*
	 * Handle target of unknown suffix...
	 */
	if (Lst_IsEmpty(&targs) && suffNull != NULL) {
		DEBUGF(SUFF, ("\tNo known suffix on %s. Using .NULL suffix\n",
		    gn->name));

		targ = SuffSrcCreate(estrdup(gn->name), estrdup(sopref),
		    suffNull, NULL, gn);
		targ->suff->refCount++;

		/*
		 * Only use the default suffix rules if we don't have commands
		 * or dependencies defined for this gnode
		 */
		if (Lst_IsEmpty(&gn->commands) && Lst_IsEmpty(&gn->children))
			SuffAddLevel(&srcs, targ);
		else {
			DEBUGF(SUFF, ("not "));
		}

		DEBUGF(SUFF, ("adding suffix rules\n"));

		Lst_AtEnd(&targs, targ);
	}

	/*
	 * Using the list of possible sources built up from the target
	 * suffix(es), try and find an existing file/target that matches.
	 */
	bottom = SuffFindThem(&srcs, slst);

	if (bottom == NULL) {
		/*
		 * No known transformations -- use the first suffix found for
		 * setting the local variables.
		 */
		if (!Lst_IsEmpty(&targs)) {
			targ = Lst_Datum(Lst_First(&targs));
		} else {
			targ = NULL;
		}
	} else {
		/*
		 * Work up the transformation path to find the suffix of the
		 * target to which the transformation was made.
		 */
		for (targ = bottom; targ->parent != NULL; targ = targ->parent)
			continue;
	}

	/*
	 * The .TARGET variable we always set to be the name at this point,
	 * since it's only set to the path if the thing is only a source and
	 * if it's only a source, it doesn't matter what we put here as far
	 * as expanding sources is concerned, since it has none...
	 */
	Var_Set(TARGET, gn->name, gn);

	pref = (targ != NULL) ? targ->pref : gn->name;
	Var_Set(PREFIX, pref, gn);

	/*
	 * Now we've got the important local variables set, expand any sources
	 * that still contain variables or wildcards in their names.
	 */
	SuffExpandChildren(gn, NULL);

	if (targ == NULL) {
		DEBUGF(SUFF, ("\tNo valid suffix on %s\n", gn->name));

  sfnd_abort:
		/*
		 * Deal with finding the thing on the default search path if the
		 * node is only a source (not on the lhs of a dependency
		 * operator or [XXX] it has neither children or commands).
		 */
		if (OP_NOP(gn->type) || (Lst_IsEmpty(&gn->children) &&
		    Lst_IsEmpty(&gn->commands))) {
			gn->path = Path_FindFile(gn->name,
			    (targ == NULL ? &dirSearchPath :
			    &targ->suff->searchPath));
			if (gn->path != NULL) {
				char *ptr;
				Var_Set(TARGET, gn->path, gn);

				if (targ != NULL) {
					/*
					 * Suffix known for the thing -- trim
					 * the suffix off the path to form the
					 * proper .PREFIX variable.
					 */
					int	savep = strlen(gn->path) -
						    targ->suff->nameLen;
					char	savec;

					if (gn->suffix)
						gn->suffix->refCount--;
					gn->suffix = targ->suff;
					gn->suffix->refCount++;

					savec = gn->path[savep];
					gn->path[savep] = '\0';

					if ((ptr = strrchr(gn->path, '/')) != NULL)
						ptr++;
					else
						ptr = gn->path;

					Var_Set(PREFIX, ptr, gn);

					gn->path[savep] = savec;
				} else {
					/*
					 * The .PREFIX gets the full path if
					 * the target has no known suffix.
					 */
					if (gn->suffix)
						gn->suffix->refCount--;
					gn->suffix = NULL;

					if ((ptr = strrchr(gn->path, '/')) != NULL)
						ptr++;
					else
						ptr = gn->path;

					Var_Set(PREFIX, ptr, gn);
				}
			}
		} else {
			/*
			 * Not appropriate to search for the thing -- set the
			 * path to be the name so Dir_MTime won't go
			 * grovelling for it.
			 */
			if (gn->suffix)
				gn->suffix->refCount--;
			gn->suffix = (targ == NULL) ? NULL : targ->suff;
			if (gn->suffix)
				gn->suffix->refCount++;
			free(gn->path);
			gn->path = estrdup(gn->name);
		}

		goto sfnd_return;
	}

	/*
	 * If the suffix indicates that the target is a library, mark that in
	 * the node's type field.
	 */
	if (targ->suff->flags & SUFF_LIBRARY) {
		gn->type |= OP_LIB;
	}

	/*
	 * Check for overriding transformation rule implied by sources
	 */
	if (!Lst_IsEmpty(&gn->children)) {
		src = SuffFindCmds(targ, slst);

		if (src != NULL) {
			/*
			 * Free up all the Src structures in the
			 * transformation path up to, but not including,
			 * the parent node.
			 */
			while (bottom && bottom->parent != NULL) {
				if (Lst_Member(slst, bottom) == NULL) {
					Lst_AtEnd(slst, bottom);
				}
				bottom = bottom->parent;
			}
			bottom = src;
		}
	}

	if (bottom == NULL) {
		/*
		 * No idea from where it can come -- return now.
		 */
		goto sfnd_abort;
	}

	/*
	 * We now have a list of Src structures headed by 'bottom' and linked
	 * via their 'parent' pointers. What we do next is create links between
	 * source and target nodes (which may or may not have been created)
	 * and set the necessary local variables in each target. The
	 * commands for each target are set from the commands of the
	 * transformation rule used to get from the src suffix to the targ
	 * suffix. Note that this causes the commands list of the original
	 * node, gn, to be replaced by the commands of the final
	 * transformation rule. Also, the unmade field of gn is incremented.
	 * Etc.
	 */
	if (bottom->node == NULL) {
		bottom->node = Targ_FindNode(bottom->file, TARG_CREATE);
	}

	for (src = bottom; src->parent != NULL; src = src->parent) {
		targ = src->parent;

		if (src->node->suffix)
			src->node->suffix->refCount--;
		src->node->suffix = src->suff;
		src->node->suffix->refCount++;

		if (targ->node == NULL) {
			targ->node = Targ_FindNode(targ->file, TARG_CREATE);
		}

		SuffApplyTransform(targ->node, src->node,
		    targ->suff, src->suff);

		if (targ->node != gn) {
			/*
			 * Finish off the dependency-search process for any
			 * nodes between bottom and gn (no point in questing
			 * around the filesystem for their implicit source
			 * when it's already known). Note that the node can't
			 * have any sources that need expanding, since
			 * SuffFindThem will stop on an existing
			 * node, so all we need to do is set the standard and
			 * System V variables.
			 */
			targ->node->type |= OP_DEPS_FOUND;

			Var_Set(PREFIX, targ->pref, targ->node);
			Var_Set(TARGET, targ->node->name, targ->node);
		}
	}

	if (gn->suffix)
		gn->suffix->refCount--;
	gn->suffix = src->suff;
	gn->suffix->refCount++;

	/*
	 * So Dir_MTime doesn't go questing for it...
	 */
	free(gn->path);
	gn->path = estrdup(gn->name);

	/*
	 * Nuke the transformation path and the Src structures left over in the
	 * two lists.
	 */
  sfnd_return:
	if (bottom)
		if (Lst_Member(slst, bottom) == NULL)
			Lst_AtEnd(slst, bottom);

	while (SuffRemoveSrc(&srcs) || SuffRemoveSrc(&targs))
		continue;

	Lst_Concat(slst, &srcs, LST_CONCLINK);
	Lst_Concat(slst, &targs, LST_CONCLINK);
}

/*-
 *-----------------------------------------------------------------------
 * Suff_FindDeps  --
 *	Find implicit sources for the target described by the graph node
 *	gn
 *
 * Results:
 *	Nothing.
 *
 * Side Effects:
 *	Nodes are added to the graph below the passed-in node. The nodes
 *	are marked to have their IMPSRC variable filled in. The
 *	PREFIX variable is set for the given node and all its
 *	implied children.
 *
 * Notes:
 *	The path found by this target is the shortest path in the
 *	transformation graph, which may pass through non-existent targets,
 *	to an existing target. The search continues on all paths from the
 *	root suffix until a file is found. I.e. if there's a path
 *	.o -> .c -> .l -> .l,v from the root and the .l,v file exists but
 *	the .c and .l files don't, the search will branch out in
 *	all directions from .o and again from all the nodes on the
 *	next level until the .l,v node is encountered.
 *
 *-----------------------------------------------------------------------
 */
void
Suff_FindDeps(GNode *gn)
{

	SuffFindDeps(gn, &srclist);
	while (SuffRemoveSrc(&srclist))
		continue;
}


static void
SuffFindDeps(GNode *gn, Lst *slst)
{

	if (gn->type & OP_DEPS_FOUND) {
		/*
		 * If dependencies already found, no need to do it again...
		 */
		return;
	} else {
		gn->type |= OP_DEPS_FOUND;
	}

	DEBUGF(SUFF, ("SuffFindDeps (%s)\n", gn->name));

	if (gn->type & OP_ARCHV) {
		SuffFindArchiveDeps(gn, slst);

	} else if (gn->type & OP_LIB) {
		/*
		* If the node is a library, it is the arch module's job to find
		* it and set the TARGET variable accordingly. We merely provide
		* the search path, assuming all libraries end in ".a" (if the
		* suffix hasn't been defined, there's nothing we can do for it,
		* so we just set the TARGET variable to the node's name in order
		* to give it a value).
		*/
		Suff	*s;

		s = SuffSuffFind(LIBSUFF);
		if (gn->suffix)
			gn->suffix->refCount--;
		if (s != NULL) {
			gn->suffix = s;
			gn->suffix->refCount++;
			Arch_FindLib(gn, &s->searchPath);
		} else {
			gn->suffix = NULL;
			Var_Set(TARGET, gn->name, gn);
		}

		/*
		* Because a library (-lfoo) target doesn't follow the standard
		* filesystem conventions, we don't set the regular variables for
		* the thing. .PREFIX is simply made empty...
		*/
		Var_Set(PREFIX, "", gn);

	} else {
		SuffFindNormalDeps(gn, slst);
	}
}

/*-
 *-----------------------------------------------------------------------
 * Suff_SetNull --
 *	Define which suffix is the null suffix.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	'suffNull' is altered.
 *
 * Notes:
 *	Need to handle the changing of the null suffix gracefully so the
 *	old transformation rules don't just go away.
 *
 *-----------------------------------------------------------------------
 */
void
Suff_SetNull(char *name)
{
	Suff	*s;

	if ((s = SuffSuffFind(name)) == NULL) {
		Parse_Error(PARSE_WARNING, "Desired null suffix %s "
		    "not defined.", name);
		return;
	}

	if (suffNull != NULL) {
		suffNull->flags &= ~SUFF_NULL;
	}
	s->flags |= SUFF_NULL;

	/*
	 * XXX: Here's where the transformation mangling
	 * would take place
	 */
	suffNull = s;
}

/*-
 *-----------------------------------------------------------------------
 * Suff_Init --
 *	Initialize suffixes module
 *
 * Results:
 *	None
 *
 * Side Effects:
 *	Many
 *-----------------------------------------------------------------------
 */
void
Suff_Init(void)
{

	sNum = 0;
	/*
	* Create null suffix for single-suffix rules (POSIX). The thing doesn't
	* actually go on the suffix list or everyone will think that's its
	* suffix.
	*/
	emptySuff = suffNull = emalloc(sizeof(Suff));

	suffNull->name = estrdup("");
	suffNull->nameLen = 0;
	TAILQ_INIT(&suffNull->searchPath);
	Path_Concat(&suffNull->searchPath, &dirSearchPath);
	Lst_Init(&suffNull->children);
	Lst_Init(&suffNull->parents);
	Lst_Init(&suffNull->ref);
	suffNull->sNum = sNum++;
	suffNull->flags = SUFF_NULL;
	suffNull->refCount = 1;
}

/********************* DEBUGGING FUNCTIONS **********************/

void
Suff_PrintAll(void)
{
	const LstNode	*ln;
	const LstNode	*tln;
	const GNode	*gn;
	const Suff	*s;

	static const struct flag2str suff_flags[] = {
		{ SUFF_INCLUDE,	"INCLUDE" },
		{ SUFF_LIBRARY,	"LIBRARY" },
		{ SUFF_NULL,	"NULL" },
		{ 0,		NULL }
	};

	printf("#*** Suffixes:\n");
	LST_FOREACH(ln, &sufflist) {
		s = Lst_Datum(ln);
		printf("# `%s' [%d] ", s->name, s->refCount);

		if (s->flags != 0) {
			printf(" ");
			print_flags(stdout, suff_flags, s->flags, 1);
		}

		printf("\n#\tTo: ");
		LST_FOREACH(tln, &s->parents)
			printf("`%s' ", ((const Suff *)Lst_Datum(tln))->name);

		printf("\n#\tFrom: ");
		LST_FOREACH(tln, &s->children)
			printf("`%s' ", ((const Suff *)Lst_Datum(tln))->name);

		printf("\n#\tSearch Path: ");
		Path_Print(&s->searchPath);

		printf("\n");
	}

	printf("#*** Transformations:\n");
	LST_FOREACH(ln, &transforms) {
		gn = Lst_Datum(ln);
		printf("%-16s: ", gn->name);
		Targ_PrintType(gn->type);
		printf("\n");
		LST_FOREACH(tln, &gn->commands)
			printf("\t%s\n", (const char *)Lst_Datum(tln));
		printf("\n");
	}
}
