/*	$OpenBSD: engine.c,v 1.9 2007/09/17 12:42:09 espie Exp $ */
/*
 * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
 * Copyright (c) 1988, 1989 by Adam de Boor
 * 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. 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.
 */

#include <limits.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include "config.h"
#include "defines.h"
#include "dir.h"
#include "engine.h"
#include "arch.h"
#include "gnode.h"
#include "targ.h"
#include "var.h"
#include "extern.h"
#include "lst.h"
#include "timestamp.h"
#include "make.h"

static void MakeTimeStamp(void *, void *);
static void MakeAddAllSrc(void *, void *);
static int rewrite_time(const char *);

bool
Job_CheckCommands(GNode *gn, void (*abortProc)(char *, ...))
{
	if (OP_NOP(gn->type) && Lst_IsEmpty(&gn->commands) &&
	    (gn->type & (OP_NODEFAULT | OP_LIB)) == 0) {
		/*
		 * No commands. Look for .DEFAULT rule from which we might infer
		 * commands
		 */
		if ((DEFAULT->type & OP_DUMMY) == 0 &&
		    !Lst_IsEmpty(&DEFAULT->commands)) {
			/*
			 * Make only looks for a .DEFAULT if the node was never
			 * the target of an operator, so that's what we do too.
			 * If a .DEFAULT was given, we substitute its commands
			 * for gn's commands and set the IMPSRC variable to be
			 * the target's name The DEFAULT node acts like a
			 * transformation rule, in that gn also inherits any
			 * attributes or sources attached to .DEFAULT itself.
			 */
			Make_HandleUse(DEFAULT, gn);
			Varq_Set(IMPSRC_INDEX, Varq_Value(TARGET_INDEX, gn), gn);
		} else if (is_out_of_date(Dir_MTime(gn))) {
			/*
			 * The node wasn't the target of an operator we have no
			 * .DEFAULT rule to go on and the target doesn't
			 * already exist. There's nothing more we can do for
			 * this branch. If the -k flag wasn't given, we stop in
			 * our tracks, otherwise we just don't update this
			 * node's parents so they never get examined.
			 */
			static const char msg[] =
			    "make: don't know how to make";

			if (gn->type & OP_OPTIONAL) {
				(void)fprintf(stdout, "%s %s(ignored)\n", msg,
				    gn->name);
				(void)fflush(stdout);
			} else if (keepgoing) {
				(void)fprintf(stdout, "%s %s(continuing)\n",
				    msg, gn->name);
				(void)fflush(stdout);
				return false;
			} else {
				(*abortProc)("%s %s. Stop in %s.", msg,
				    gn->name, Var_Value(".CURDIR"));
				return false;
			}
		}
	}
	return true;
}

/* touch files the hard way, by writing stuff to them */
static int
rewrite_time(const char *name)
{
	int fd;
	char c;

	fd = open(name, O_RDWR | O_CREAT, 0666);
	if (fd < 0)
		return -1;
	/*
	 * Read and write a byte to the file to change
	 * the modification time.
	 */
	if (read(fd, &c, 1) == 1) {
		(void)lseek(fd, 0, SEEK_SET);
		(void)write(fd, &c, 1);
	}

	(void)close(fd);
	return 0;
}

void
Job_Touch(GNode *gn, bool silent)
{
	if (gn->type & (OP_JOIN|OP_USE|OP_EXEC|OP_OPTIONAL)) {
		/*
		 * .JOIN, .USE, and .OPTIONAL targets are "virtual" targets
		 * and, as such, shouldn't really be created.
		 */
		return;
	}

	if (!silent) {
		(void)fprintf(stdout, "touch %s\n", gn->name);
		(void)fflush(stdout);
	}

	if (noExecute) {
		return;
	}

	if (gn->type & OP_ARCHV) {
		Arch_Touch(gn);
	} else if (gn->type & OP_LIB) {
		Arch_TouchLib(gn);
	} else {
		const char *file = gn->path != NULL ? gn->path : gn->name;

		if (set_times(file) == -1){
			if (rewrite_time(file) == -1) {
				(void)fprintf(stdout,
				    "*** couldn't touch %s: %s", file,
				    strerror(errno));
				(void)fflush(stdout);
		    	}
		}
	}
}

void
Make_TimeStamp(GNode *parent, GNode *child)
{
	if (is_strictly_before(parent->cmtime, child->mtime))
		parent->cmtime = child->mtime;
}

void
Make_HandleUse(GNode	*cgn,	/* The .USE node */
    GNode	*pgn)	/* The target of the .USE node */
{
	GNode	*gn;	/* A child of the .USE node */
	LstNode	ln;	/* An element in the children list */

	if (cgn->type & (OP_USE|OP_TRANSFORM)) {
		if ((cgn->type & OP_USE) || Lst_IsEmpty(&pgn->commands)) {
			/* .USE or transformation and target has no commands
			 * -- append the child's commands to the parent.  */
			Lst_Concat(&pgn->commands, &cgn->commands);
		}

		for (ln = Lst_First(&cgn->children); ln != NULL;
		    ln = Lst_Adv(ln)) {
			gn = (GNode *)Lst_Datum(ln);

			if (Lst_AddNew(&pgn->children, gn)) {
				Lst_AtEnd(&gn->parents, pgn);
				pgn->unmade++;
			}
		}

		pgn->type |= cgn->type & ~(OP_OPMASK|OP_USE|OP_TRANSFORM);

		/*
		 * This child node is now "made", so we decrement the count of
		 * unmade children in the parent... We also remove the child
		 * from the parent's list to accurately reflect the number of
		 * decent children the parent has. This is used by Make_Run to
		 * decide whether to queue the parent or examine its children...
		 */
		if (cgn->type & OP_USE)
			pgn->unmade--;
	}
}

static void
MakeAddAllSrc(void *cgnp, void *pgnp)
{
	GNode	*child = (GNode *)cgnp;
	GNode	*parent = (GNode *)pgnp;
	if ((child->type & (OP_EXEC|OP_USE|OP_INVISIBLE)) == 0) {
		const char *target;

		if (OP_NOP(child->type) ||
		    (target = Varq_Value(TARGET_INDEX, child)) == NULL) {
			/*
			 * this node is only source; use the specific pathname
			 * for it
			 */
			target = child->path != NULL ? child->path :
			    child->name;
		}

		Varq_Append(ALLSRC_INDEX, target, parent);
		if (parent->type & OP_JOIN) {
			if (child->made == MADE)
				Varq_Append(OODATE_INDEX, target, parent);
		} else if (is_strictly_before(parent->mtime, child->mtime) ||
		   (!is_strictly_before(child->mtime, now) &&
		   child->made == MADE)) {
			/*
			 * It goes in the OODATE variable if the parent is
			 * younger than the child or if the child has been
			 * modified more recently than the start of the make.
			 * This is to keep make from getting confused if
			 * something else updates the parent after the
			 * make starts (shouldn't happen, I know, but sometimes
			 * it does). In such a case, if we've updated the kid,
			 * the parent is likely to have a modification time
			 * later than that of the kid and anything that relies
			 * on the OODATE variable will be hosed.
			 */
			Varq_Append(OODATE_INDEX, target, parent);
		}
	}
}

void
Make_DoAllVar(GNode *gn)
{
	Lst_ForEach(&gn->children, MakeAddAllSrc, gn);

	if (Varq_Value(OODATE_INDEX, gn) == NULL)
		Varq_Set(OODATE_INDEX, "", gn);
	if (Varq_Value(ALLSRC_INDEX, gn) == NULL)
		Varq_Set(ALLSRC_INDEX, "", gn);

	if (gn->type & OP_JOIN)
		Varq_Set(TARGET_INDEX, Varq_Value(ALLSRC_INDEX, gn), gn);
}

/* Wrapper to call Make_TimeStamp from a forEach loop.	*/
static void
MakeTimeStamp(void *parent, void *child)
{
    Make_TimeStamp((GNode *)parent, (GNode *)child);
}

bool
Make_OODate(GNode *gn)
{
	bool	    oodate;

	/*
	 * Certain types of targets needn't even be sought as their datedness
	 * doesn't depend on their modification time...
	 */
	if ((gn->type & (OP_JOIN|OP_USE|OP_EXEC)) == 0) {
		(void)Dir_MTime(gn);
		if (DEBUG(MAKE)) {
			if (!is_out_of_date(gn->mtime))
				printf("modified %s...",
				    time_to_string(gn->mtime));
			else
				printf("non-existent...");
		}
	}

	/*
	 * A target is remade in one of the following circumstances:
	 * - its modification time is smaller than that of its youngest child
	 *   and it would actually be run (has commands or type OP_NOP)
	 * - it's the object of a force operator
	 * - it has no children, was on the lhs of an operator and doesn't
	 *   exist already.
	 *
	 * Libraries are only considered out-of-date if the archive module says
	 * they are.
	 */
	if (gn->type & OP_USE) {
		/*
		 * If the node is a USE node it is *never* out of date
		 * no matter *what*.
		 */
		if (DEBUG(MAKE))
			printf(".USE node...");
		oodate = false;
	} else if ((gn->type & OP_LIB) && Arch_IsLib(gn)) {
		if (DEBUG(MAKE))
		    printf("library...");

		/* always out of date if no children and :: target */
		oodate = Arch_LibOODate(gn) ||
		    (is_out_of_date(gn->cmtime) && (gn->type & OP_DOUBLEDEP));
	} else if (gn->type & OP_JOIN) {
		/*
		 * A target with the .JOIN attribute is only considered
		 * out-of-date if any of its children was out-of-date.
		 */
		if (DEBUG(MAKE))
			printf(".JOIN node...");
		oodate = gn->childMade;
	} else if (gn->type & (OP_FORCE|OP_EXEC|OP_PHONY)) {
		/*
		 * A node which is the object of the force (!) operator or which
		 * has the .EXEC attribute is always considered out-of-date.
		 */
		if (DEBUG(MAKE)) {
			if (gn->type & OP_FORCE)
				printf("! operator...");
			else if (gn->type & OP_PHONY)
				printf(".PHONY node...");
			else
				printf(".EXEC node...");
		}
		oodate = true;
	} else if (is_strictly_before(gn->mtime, gn->cmtime) ||
	   (is_out_of_date(gn->cmtime) &&
	    (is_out_of_date(gn->mtime) || (gn->type & OP_DOUBLEDEP)))) {
		/*
		 * A node whose modification time is less than that of its
		 * youngest child or that has no children (cmtime ==
		 * OUT_OF_DATE) and either doesn't exist (mtime == OUT_OF_DATE)
		 * or was the object of a :: operator is out-of-date.
		 */
		if (DEBUG(MAKE)) {
			if (is_strictly_before(gn->mtime, gn->cmtime))
				printf("modified before source...");
			else if (is_out_of_date(gn->mtime))
				printf("non-existent and no sources...");
			else
				printf(":: operator and no sources...");
		}
		oodate = true;
	} else {
		oodate = false;
	}

	/*
	 * If the target isn't out-of-date, the parents need to know its
	 * modification time. Note that targets that appear to be out-of-date
	 * but aren't, because they have no commands and aren't of type OP_NOP,
	 * have their mtime stay below their children's mtime to keep parents
	 * from thinking they're out-of-date.
	 */
	if (!oodate)
		Lst_ForEach(&gn->parents, MakeTimeStamp, gn);

	return oodate;
}