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Commit e298f3b4 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

kconfig: add built-in function support 



This commit adds a new concept 'function' to do more text processing
in Kconfig.

A function call looks like this:

  $(function,arg1,arg2,arg3,...)

This commit adds the basic infrastructure to expand functions.
Change the text expansion helpers to take arguments.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
parent 137c0118

scripts/kconfig/preprocess.c

+130 −12
Original line number Diff line number Diff line
@@ -10,6 +10,10 @@ 


#include "list.h"



#define ARRAY_SIZE(arr)		(sizeof(arr) / sizeof((arr)[0]))



static char *expand_string_with_args(const char *in, int argc, char *argv[]);



static void __attribute__((noreturn)) pperror(const char *format, ...)

{

	va_list ap;
@@ -92,20 +96,123 @@ void env_write_dep(FILE *f, const char *autoconfig_name) 
	}

}



static char *eval_clause(const char *str, size_t len)

/*

 * Built-in functions

 */

struct function {

	const char *name;

	unsigned int min_args;

	unsigned int max_args;

	char *(*func)(int argc, char *argv[]);

};



static const struct function function_table[] = {

	/* Name		MIN	MAX	Function */

};



#define FUNCTION_MAX_ARGS		16



static char *function_expand(const char *name, int argc, char *argv[])

{

	const struct function *f;

	int i;



	for (i = 0; i < ARRAY_SIZE(function_table); i++) {

		f = &function_table[i];

		if (strcmp(f->name, name))

			continue;



		if (argc < f->min_args)

			pperror("too few function arguments passed to '%s'",

				name);



		if (argc > f->max_args)

			pperror("too many function arguments passed to '%s'",

				name);



		return f->func(argc, argv);

	}



	return NULL;

}



/*

 * Evaluate a clause with arguments.  argc/argv are arguments from the upper

 * function call.

 *

 * Returned string must be freed when done

 */

static char *eval_clause(const char *str, size_t len, int argc, char *argv[])

{

	char *tmp, *name, *res;

	char *tmp, *name, *res, *prev, *p;

	int new_argc = 0;

	char *new_argv[FUNCTION_MAX_ARGS];

	int nest = 0;

	int i;



	tmp = xstrndup(str, len);



	name = expand_string(tmp);

	prev = p = tmp;



	/*

	 * Split into tokens

	 * The function name and arguments are separated by a comma.

	 * For example, if the function call is like this:

	 *   $(foo,$(x),$(y))

	 *

	 * The input string for this helper should be:

	 *   foo,$(x),$(y)

	 *

	 * and split into:

	 *   new_argv[0] = 'foo'

	 *   new_argv[1] = '$(x)'

	 *   new_argv[2] = '$(y)'

	 */

	while (*p) {

		if (nest == 0 && *p == ',') {

			*p = 0;

			if (new_argc >= FUNCTION_MAX_ARGS)

				pperror("too many function arguments");

			new_argv[new_argc++] = prev;

			prev = p + 1;

		} else if (*p == '(') {

			nest++;

		} else if (*p == ')') {

			nest--;

		}



		p++;

	}

	new_argv[new_argc++] = prev;



	/*

	 * Shift arguments

	 * new_argv[0] represents a function name or a variable name.  Put it

	 * into 'name', then shift the rest of the arguments.  This simplifies

	 * 'const' handling.

	 */

	name = expand_string_with_args(new_argv[0], argc, argv);

	new_argc--;

	for (i = 0; i < new_argc; i++)

		new_argv[i] = expand_string_with_args(new_argv[i + 1],

						      argc, argv);



	/* Look for built-in functions */

	res = function_expand(name, new_argc, new_argv);

	if (res)

		goto free;



	/* Last, try environment variable */

	if (new_argc == 0) {

		res = env_expand(name);

		if (res)

			goto free;

	}



	res = xstrdup("");

free:

	for (i = 0; i < new_argc; i++)

		free(new_argv[i]);

	free(name);

	free(tmp);
@@ -124,14 +231,14 @@ static char *eval_clause(const char *str, size_t len) 
 * after the corresponding closing parenthesis, in this case, *str will be

 *     $(BAR)

 */

char *expand_dollar(const char **str)

static char *expand_dollar_with_args(const char **str, int argc, char *argv[])

{

	const char *p = *str;

	const char *q;

	int nest = 0;



	/*

	 * In Kconfig, variable references always start with "$(".

	 * In Kconfig, variable/function references always start with "$(".

	 * Neither single-letter variables as in $A nor curly braces as in ${CC}

	 * are supported.  '$' not followed by '(' loses its special meaning.

	 */
@@ -158,10 +265,16 @@ char *expand_dollar(const char **str) 
	/* Advance 'str' to after the expanded initial portion of the string */

	*str = q + 1;



	return eval_clause(p, q - p);

	return eval_clause(p, q - p, argc, argv);

}



char *expand_dollar(const char **str)

{

	return expand_dollar_with_args(str, 0, NULL);

}



static char *__expand_string(const char **str, bool (*is_end)(char c))

static char *__expand_string(const char **str, bool (*is_end)(char c),

			     int argc, char *argv[])

{

	const char *in, *p;

	char *expansion, *out;
@@ -177,7 +290,7 @@ static char *__expand_string(const char **str, bool (*is_end)(char c)) 
		if (*p == '$') {

			in_len = p - in;

			p++;

			expansion = expand_dollar(&p);

			expansion = expand_dollar_with_args(&p, argc, argv);

			out_len += in_len + strlen(expansion);

			out = xrealloc(out, out_len);

			strncat(out, in, in_len);
@@ -210,13 +323,18 @@ static bool is_end_of_str(char c) 
}



/*

 * Expand variables in the given string.  Undefined variables

 * Expand variables and functions in the given string.  Undefined variables

 * expand to an empty string.

 * The returned string must be freed when done.

 */

static char *expand_string_with_args(const char *in, int argc, char *argv[])

{

	return __expand_string(&in, is_end_of_str, argc, argv);

}



char *expand_string(const char *in)

{

	return __expand_string(&in, is_end_of_str);

	return expand_string_with_args(in, 0, NULL);

}



static bool is_end_of_token(char c)
@@ -234,5 +352,5 @@ static bool is_end_of_token(char c) 
 */

char *expand_one_token(const char **str)

{

	return __expand_string(str, is_end_of_token);

	return __expand_string(str, is_end_of_token, 0, NULL);

}