Module Name: src
Committed By: rillig
Date: Tue Sep 8 18:51:23 UTC 2020
Modified Files:
src/usr.bin/make: cond.c
Log Message:
make(1): clean up comments in cond.c
To generate a diff of this commit:
cvs rdiff -u -r1.116 -r1.117 src/usr.bin/make/cond.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/usr.bin/make/cond.c
diff -u src/usr.bin/make/cond.c:1.116 src/usr.bin/make/cond.c:1.117
--- src/usr.bin/make/cond.c:1.116 Tue Sep 8 18:10:34 2020
+++ src/usr.bin/make/cond.c Tue Sep 8 18:51:23 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: cond.c,v 1.116 2020/09/08 18:10:34 rillig Exp $ */
+/* $NetBSD: cond.c,v 1.117 2020/09/08 18:51:23 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -70,25 +70,34 @@
*/
#ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: cond.c,v 1.116 2020/09/08 18:10:34 rillig Exp $";
+static char rcsid[] = "$NetBSD: cond.c,v 1.117 2020/09/08 18:51:23 rillig Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)cond.c 8.2 (Berkeley) 1/2/94";
#else
-__RCSID("$NetBSD: cond.c,v 1.116 2020/09/08 18:10:34 rillig Exp $");
+__RCSID("$NetBSD: cond.c,v 1.117 2020/09/08 18:51:23 rillig Exp $");
#endif
#endif /* not lint */
#endif
-/*-
- * cond.c --
- * Functions to handle conditionals in a makefile.
+/* Handling of conditionals in a makefile.
*
* Interface:
* Cond_Eval Evaluate the conditional in the passed line.
*
+ * Cond_EvalExpression
+ * Evaluate the conditional in the passed line, which
+ * is either the argument of one of the .if directives
+ * or the condition in a :?true:false variable modifier.
+ *
+ * Cond_save_depth
+ * Cond_restore_depth
+ * Save and restore the nesting of the conditions, at
+ * the start and end of including another makefile, to
+ * ensure that in each makefile the conditional
+ * directives are well-balanced.
*/
#include <errno.h>
@@ -119,7 +128,7 @@ __RCSID("$NetBSD: cond.c,v 1.116 2020/09
*
* 'symbol' is some other symbol to which the default function is applied.
*
- * Tokens are scanned from the 'condExpr' string. The scanner (CondToken)
+ * Tokens are scanned from the lexer. The scanner (CondToken)
* will return TOK_AND for '&' and '&&', TOK_OR for '|' and '||',
* TOK_NOT for '!', TOK_LPAREN for '(', TOK_RPAREN for ')' and will evaluate
* the other terminal symbols, using either the default function or the
@@ -150,6 +159,9 @@ static unsigned int cond_min_depth = 0;
/*
* Indicate when we should be strict about lhs of comparisons.
+ * In strict mode, the lhs must be a variable expression or a string literal
+ * in quotes. In non-strict mode it may also be an unquoted string literal.
+ *
* TRUE when Cond_EvalExpression is called from Cond_Eval (.if etc)
* FALSE when Cond_EvalExpression is called from var.c:ApplyModifiers
* since lhs is already expanded and we cannot tell if
@@ -191,9 +203,6 @@ CondLexer_SkipWhitespace(CondLexer *lex)
* func says whether the argument belongs to an actual function, or
* whether the parsed argument is passed to the default function.
*
- * XXX: This is ambiguous for the empty() function since its argument is
- * parsed differently.
- *
* Return the length of the argument. */
static int
ParseFuncArg(Boolean doEval, const char **linePtr, char **out_arg,
@@ -241,7 +250,7 @@ ParseFuncArg(Boolean doEval, const char
/*
* Parse the variable spec and install it as part of the argument
* if it's valid. We tell Var_Parse to complain on an undefined
- * variable, so we don't do it too. Nor do we return an error,
+ * variable, so we don't need to do it. Nor do we return an error,
* though perhaps we should...
*/
void *freeIt;
@@ -380,18 +389,15 @@ CondCvtArg(const char *str, double *valu
}
/*-
- * Get a string from a variable reference or an optionally quoted
+ * Parse a string from a variable reference or an optionally quoted
* string. This is called for the lhs and rhs of string compares.
*
* Results:
* Returns the string, absent any quotes, or NULL on error.
* Sets quoted if the string was quoted.
* Sets freeIt if needed.
- *
- * Side Effects:
- * Moves condExpr past the end of this token.
*/
-/* coverity:[+alloc : arg-*2] */
+/* coverity:[+alloc : arg-*3] */
static const char *
CondGetString(CondLexer *lex, Boolean doEval, Boolean *quoted, void **freeIt,
Boolean strictLHS)
@@ -498,7 +504,7 @@ cleanup:
return str;
}
-/* The different forms of #if's. */
+/* The different forms of .if directives. */
static const struct If {
const char *form; /* Form of if */
size_t formlen; /* Length of form */
@@ -513,12 +519,6 @@ static const struct If {
{ NULL, 0, FALSE, NULL }
};
-/*-
- * Return the next token from the input.
- *
- * Side Effects:
- * condPushback will be set back to TOK_NONE if it is used.
- */
static Token
compare_expression(CondLexer *lex, Boolean doEval)
{
@@ -788,7 +788,7 @@ compare_function(CondLexer *lex, Boolean
/*
* Evaluate the argument using the default function.
- * This path always treats .if as .ifdef. To get here the character
+ * This path always treats .if as .ifdef. To get here, the character
* after .if must have been taken literally, so the argument cannot
* be empty - even if it contained a variable expansion.
*/
@@ -797,6 +797,7 @@ compare_function(CondLexer *lex, Boolean
return t;
}
+/* Return the next token or comparison result from the lexer. */
static Token
CondToken(CondLexer *lex, Boolean doEval)
{
@@ -854,22 +855,14 @@ CondToken(CondLexer *lex, Boolean doEval
}
}
-/*-
- *-----------------------------------------------------------------------
- * CondT --
- * Parse a single term in the expression. This consists of a terminal
- * symbol or TOK_NOT and a terminal symbol (not including the binary
- * operators):
- * T -> defined(variable) | make(target) | exists(file) | symbol
- * T -> ! T | ( E )
+/* Parse a single term in the expression. This consists of a terminal symbol
+ * or TOK_NOT and a term (not including the binary operators):
+ *
+ * T -> defined(variable) | make(target) | exists(file) | symbol
+ * T -> ! T | ( E )
*
* Results:
* TOK_TRUE, TOK_FALSE or TOK_ERROR.
- *
- * Side Effects:
- * Tokens are consumed.
- *
- *-----------------------------------------------------------------------
*/
static Token
CondT(CondLexer *lex, Boolean doEval)
@@ -905,19 +898,12 @@ CondT(CondLexer *lex, Boolean doEval)
return t;
}
-/*-
- *-----------------------------------------------------------------------
- * CondF --
- * Parse a conjunctive factor (nice name, wot?)
- * F -> T && F | T
+/* Parse a conjunctive factor (nice name, wot?)
+ *
+ * F -> T && F | T
*
* Results:
* TOK_TRUE, TOK_FALSE or TOK_ERROR
- *
- * Side Effects:
- * Tokens are consumed.
- *
- *-----------------------------------------------------------------------
*/
static Token
CondF(CondLexer *lex, Boolean doEval)
@@ -932,9 +918,10 @@ CondF(CondLexer *lex, Boolean doEval)
/*
* F -> T && F
*
- * If T is TOK_FALSE, the whole thing will be TOK_FALSE, but we have to
- * parse the r.h.s. anyway (to throw it away).
- * If T is TOK_TRUE, the result is the r.h.s., be it an TOK_ERROR or no.
+ * If T is TOK_FALSE, the whole thing will be TOK_FALSE, but we
+ * have to parse the r.h.s. anyway (to throw it away).
+ * If T is TOK_TRUE, the result is the r.h.s., be it a TOK_ERROR
+ * or not.
*/
if (l == TOK_TRUE) {
l = CondF(lex, doEval);
@@ -951,19 +938,12 @@ CondF(CondLexer *lex, Boolean doEval)
return l;
}
-/*-
- *-----------------------------------------------------------------------
- * CondE --
- * Main expression production.
- * E -> F || E | F
+/* Main expression production.
+ *
+ * E -> F || E | F
*
* Results:
* TOK_TRUE, TOK_FALSE or TOK_ERROR.
- *
- * Side Effects:
- * Tokens are, of course, consumed.
- *
- *-----------------------------------------------------------------------
*/
static Token
CondE(CondLexer *lex, Boolean doEval)
