add !!=

feedback and okay millert@

5 files changed, 76 insertions, 18 deletions

diff --git a/usr.bin/make/make.1 b/usr.bin/make/make.1
index 0a430ba29f9..dfab4bb19ef 100644
--- a/usr.bin/make/make.1
+++ b/usr.bin/make/make.1
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: make.1,v 1.120 2015/03/13 19:58:41 jmc Exp $
+.\"	$OpenBSD: make.1,v 1.121 2016/10/23 14:54:14 espie Exp $
 .\"	$NetBSD: make.1,v 1.18 1997/03/10 21:19:53 christos Exp $
 .\"
 .\" Copyright (c) 1990, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
 .\"
-.Dd $Mdocdate: March 13 2015 $
+.Dd $Mdocdate: October 23 2016 $
 .Dt MAKE 1
 .Os
 .Sh NAME
@@ -530,13 +530,26 @@ extension
 .Pc .
 Normally, expansion is not done until the variable is referenced.
 .It Ic \&!=
-Expand the value and pass it to the shell for execution and assign
-the result to the variable.
-Any newlines in the result are replaced with spaces
+Perform variable expansion and pass the result to the shell for 
+execution on the spot, assigning the result to the variable.
+Any newlines in the result are also replaced with spaces
 .Po
 .Bx
 extension
 .Pc .
+.It Ic \&!!=
+Perform variable expansion on the spot and pass the result to the shell 
+for execution only when the value is needed, assigning the result to 
+the variable.
+.Pp
+This is almost identical to
+.Ic \&!=
+except that a shell is only run when the variable value is needed.
+Any newlines in the result are also replaced with spaces
+.Po
+.Ox
+extension
+.Pc .
 .El
 .Pp
 Any whitespace before the assigned
@@ -558,6 +571,12 @@ if
 .Va A
 is not yet defined.
 .Pp
+Combinations that do not make sense, such as
+.Bd -literal -offset indent
+A +!!= cmd
+.Ed
+will not work.
+.Pp
 Variables are expanded by surrounding the variable name with either
 curly braces
 .Pq Ql {}
diff --git a/usr.bin/make/parse.c b/usr.bin/make/parse.c
index ce6f424f8fd..a1dedd1240b 100644
--- a/usr.bin/make/parse.c
+++ b/usr.bin/make/parse.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.c,v 1.117 2016/10/21 16:12:38 espie Exp $	*/
+/*	$OpenBSD: parse.c,v 1.118 2016/10/23 14:54:14 espie Exp $	*/
 /*	$NetBSD: parse.c,v 1.29 1997/03/10 21:20:04 christos Exp $	*/
 
 /*
@@ -1321,7 +1321,7 @@ handle_poison(const char *line)
 		    line);
 		return false;
 	} else {
-		Var_MarkPoisoned(name, ename, type);
+		Var_Mark(name, ename, type);
 		return true;
 	}
 }
diff --git a/usr.bin/make/parsevar.c b/usr.bin/make/parsevar.c
index 5c00622238a..80791272767 100644
--- a/usr.bin/make/parsevar.c
+++ b/usr.bin/make/parsevar.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parsevar.c,v 1.15 2013/11/22 15:47:35 espie Exp $	*/
+/*	$OpenBSD: parsevar.c,v 1.16 2016/10/23 14:54:14 espie Exp $	*/
 /*	$NetBSD: parse.c,v 1.29 1997/03/10 21:20:04 christos Exp $	*/
 
 /*
@@ -79,6 +79,8 @@ parse_variable_assignment(const char *line, int ctxt)
 #define VAR_APPEND	2
 #define VAR_SHELL	4
 #define VAR_OPT		8
+#define VAR_LAZYSHELL	16
+#define VAR_SUNSHELL	32
 	int type;
 	struct Name name;
 
@@ -90,11 +92,14 @@ parse_variable_assignment(const char *line, int ctxt)
 
 	type = VAR_NORMAL;
 
+	/* double operators (except for :) are forbidden */
+	/* OPT and APPEND don't match */
+	/* APPEND and LAZYSHELL can't really work */
 	while (*arg != '=') {
 		/* Check operator type.  */
 		switch (*arg++) {
 		case '+':
-			if (type & (VAR_OPT|VAR_APPEND))
+			if (type & (VAR_OPT|VAR_LAZYSHELL|VAR_APPEND))
 				type = VAR_INVALID;
 			else
 				type |= VAR_APPEND;
@@ -110,7 +115,7 @@ parse_variable_assignment(const char *line, int ctxt)
 		case ':':
 			if (FEATURES(FEATURE_SUNSHCMD) &&
 			    strncmp(arg, "sh", 2) == 0) {
-				type = VAR_SHELL;
+				type = VAR_SUNSHELL;
 				arg += 2;
 				while (*arg != '=' && *arg != '\0')
 					arg++;
@@ -123,7 +128,12 @@ parse_variable_assignment(const char *line, int ctxt)
 			break;
 
 		case '!':
-			if (type & VAR_SHELL)
+			if (type & VAR_SHELL) {
+				if (type & (VAR_APPEND))
+					type = VAR_INVALID;
+				else
+					type = VAR_LAZYSHELL;
+			} else if (type & (VAR_LAZYSHELL|VAR_SUNSHELL))
 				type = VAR_INVALID;
 			else
 				type |= VAR_SHELL;
@@ -147,7 +157,7 @@ parse_variable_assignment(const char *line, int ctxt)
 		VarName_Free(&name);
 		return true;
 	}
-	if (type & VAR_SHELL) {
+	if (type & (VAR_SHELL|VAR_SUNSHELL)) {
 		char *err;
 
 		if (strchr(arg, '$') != NULL) {
@@ -164,6 +174,13 @@ parse_variable_assignment(const char *line, int ctxt)
 			Parse_Error(PARSE_WARNING, err, arg);
 		arg = res1;
 	}
+	if (type & VAR_LAZYSHELL) {
+		if (strchr(arg, '$') != NULL) {
+			/* There's a dollar sign in the command, so perform
+			 * variable expansion on the whole thing. */
+			arg = Var_Subst(arg, NULL, true);
+		}
+	}
 	if (type & VAR_SUBST) {
 		/*
 		 * Allow variables in the old value to be undefined, but leave
@@ -195,6 +212,8 @@ parse_variable_assignment(const char *line, int ctxt)
 		Var_Appendi_with_ctxt(name.s, name.e, arg, ctxt);
 	else
 		Var_Seti_with_ctxt(name.s, name.e, arg, ctxt);
+	if (type & VAR_LAZYSHELL)
+		Var_Mark(name.s, name.e, VAR_EXEC_LATER);
 
 	VarName_Free(&name);
 	free(res2);
diff --git a/usr.bin/make/var.c b/usr.bin/make/var.c
index 94853d6b7d9..0ed3654bc36 100644
--- a/usr.bin/make/var.c
+++ b/usr.bin/make/var.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: var.c,v 1.100 2016/10/14 09:27:21 natano Exp $	*/
+/*	$OpenBSD: var.c,v 1.101 2016/10/23 14:54:14 espie Exp $	*/
 /*	$NetBSD: var.c,v 1.18 1997/03/18 19:24:46 christos Exp $	*/
 
 /*
@@ -72,6 +72,7 @@
 #include "config.h"
 #include "defines.h"
 #include "buf.h"
+#include "cmd_exec.h"
 #include "stats.h"
 #include "pathnames.h"
 #include "varmodifiers.h"
@@ -241,7 +242,10 @@ static void fill_from_env(Var *);
 static Var *create_var(const char *, const char *);
 static void var_set_initial_value(Var *, const char *);
 static void var_set_value(Var *, const char *);
-#define var_get_value(v)	Buf_Retrieve(&((v)->val))
+#define var_get_value(v)	((v)->flags & VAR_EXEC_LATER ? \
+	var_exec_cmd(v) : \
+	Buf_Retrieve(&((v)->val)))
+static char *var_exec_cmd(Var *);
 static void var_append_value(Var *, const char *);
 static void poison_check(Var *);
 static void var_set_append(const char *, const char *, const char *, int, bool);
@@ -538,10 +542,10 @@ find_global_var(const char *name, const char *ename, uint32_t k)
 	return v;
 }
 
-/* mark variable as poisoned, in a given setup.
+/* mark variable with special flags, in a given setup.
  */
 void
-Var_MarkPoisoned(const char *name, const char *ename, unsigned int type)
+Var_Mark(const char *name, const char *ename, unsigned int type)
 {
 	Var   *v;
 	uint32_t	k;
@@ -680,6 +684,21 @@ Var_Appendi_with_ctxt(const char *name, const char *ename, const char *val,
 	var_set_append(name, ename, val, ctxt, true);
 }
 
+static char *
+var_exec_cmd(Var *v)
+{
+	char *arg = Buf_Retrieve(&(v->val));
+	char *err;
+	char *res1;
+	res1 = Cmd_Exec(arg, &err);
+	if (err)
+		Parse_Error(PARSE_WARNING, err, arg);
+	var_set_value(v, res1);
+	free(res1);
+	v->flags &= ~VAR_EXEC_LATER;
+	return Buf_Retrieve(&(v->val));
+}
+
 /* XXX different semantics for Var_Valuei() and Var_Definedi():
  * references to poisoned value variables will error out in Var_Valuei(),
  * but not in Var_Definedi(), so the following construct works:
diff --git a/usr.bin/make/var.h b/usr.bin/make/var.h
index 6083bffc24f..e7246a331fc 100644
--- a/usr.bin/make/var.h
+++ b/usr.bin/make/var.h
@@ -1,6 +1,6 @@
 #ifndef VAR_H
 #define VAR_H
-/* $OpenBSD: var.h,v 1.18 2016/10/14 09:27:21 natano Exp $ */
+/* $OpenBSD: var.h,v 1.19 2016/10/23 14:54:14 espie Exp $ */
 /*
  * Copyright (c) 2001 Marc Espie.
  *
@@ -161,6 +161,7 @@ extern bool	errorIsOkay;
 #define POISON_NORMAL		64
 #define POISON_EMPTY		128
 #define POISON_NOT_DEFINED	256
+#define VAR_EXEC_LATER		512
 
-extern void Var_MarkPoisoned(const char *, const char *, unsigned int);
+extern void Var_Mark(const char *, const char *, unsigned int);
 #endif