From: Masahiro Yamada Date: Mon, 28 May 2018 09:21:45 +0000 (+0900) Subject: kconfig: add built-in function support X-Git-Url: https://jxself.org/git/?a=commitdiff_plain;h=a6b2c7e5248c8300ebb3393d746ec20ca92cabc3;p=carl9170fw.git 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: Masahiro Yamada Signed-off-by: Christian Lamparter --- diff --git a/config/preprocess.c b/config/preprocess.c index a2eb2eb..f32a496 100644 --- a/config/preprocess.c +++ b/config/preprocess.c @@ -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[]) { - char *tmp, *name, *res; + 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, *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--; + } - res = env_expand(name); + 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 @@ free: * 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); }