source: kBuild/vendor/gnumake/2008-10-28/variable.h

/* Definitions for using variables in GNU Make.
Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software
Foundation, Inc.
This file is part of GNU Make.

GNU Make is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3 of the License, or (at your option) any later
version.

GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "hash.h"

/* Codes in a variable definition saying where the definition came from.
   Increasing numeric values signify less-overridable definitions.  */
enum variable_origin
  {
    o_default,          /* Variable from the default set.  */
    o_env,              /* Variable from environment.  */
    o_file,             /* Variable given in a makefile.  */
    o_env_override,     /* Variable from environment, if -e.  */
    o_command,          /* Variable given by user.  */
    o_override,         /* Variable from an `override' directive.  */
    o_automatic,        /* Automatic variable -- cannot be set.  */
    o_invalid           /* Core dump time.  */
  };

enum variable_flavor
  {
    f_bogus,            /* Bogus (error) */
    f_simple,           /* Simple definition (:=) */
    f_recursive,        /* Recursive definition (=) */
    f_append,           /* Appending definition (+=) */
    f_conditional       /* Conditional definition (?=) */
  };

/* Structure that represents one variable definition.
   Each bucket of the hash table is a chain of these,
   chained through `next'.  */

#define EXP_COUNT_BITS  15      /* This gets all the bitfields into 32 bits */
#define EXP_COUNT_MAX   ((1<<EXP_COUNT_BITS)-1)

struct variable
  {
    char *name;                 /* Variable name.  */
    int length;                 /* strlen (name) */
    char *value;                /* Variable value.  */
    struct floc fileinfo;       /* Where the variable was defined.  */
    unsigned int recursive:1;   /* Gets recursively re-evaluated.  */
    unsigned int append:1;      /* Nonzero if an appending target-specific
                                   variable.  */
    unsigned int conditional:1; /* Nonzero if set with a ?=. */
    unsigned int per_target:1;  /* Nonzero if a target-specific variable.  */
    unsigned int special:1;     /* Nonzero if this is a special variable. */
    unsigned int exportable:1;  /* Nonzero if the variable _could_ be
                                   exported.  */
    unsigned int expanding:1;   /* Nonzero if currently being expanded.  */
    unsigned int exp_count:EXP_COUNT_BITS;
                                /* If >1, allow this many self-referential
                                   expansions.  */
    enum variable_flavor
      flavor ENUM_BITFIELD (3); /* Variable flavor.  */
    enum variable_origin
      origin ENUM_BITFIELD (3); /* Variable origin.  */
    enum variable_export
      {
        v_export,               /* Export this variable.  */
        v_noexport,             /* Don't export this variable.  */
        v_ifset,                /* Export it if it has a non-default value.  */
        v_default               /* Decide in target_environment.  */
      } export ENUM_BITFIELD (2);
  };

/* Structure that represents a variable set.  */

struct variable_set
  {
    struct hash_table table;    /* Hash table of variables.  */
  };

/* Structure that represents a list of variable sets.  */

struct variable_set_list
  {
    struct variable_set_list *next;     /* Link in the chain.  */
    struct variable_set *set;           /* Variable set.  */
  };

/* Structure used for pattern-specific variables.  */

struct pattern_var
  {
    struct pattern_var *next;
    const char *suffix;
    const char *target;
    unsigned int len;
    struct variable variable;
  };

extern char *variable_buffer;
extern struct variable_set_list *current_variable_set_list;

/* expand.c */
char *variable_buffer_output (char *ptr, const char *string, unsigned int length);
char *variable_expand (const char *line);
char *variable_expand_for_file (const char *line, struct file *file);
char *allocated_variable_expand_for_file (const char *line, struct file *file);
#define allocated_variable_expand(line) \
  allocated_variable_expand_for_file (line, (struct file *) 0)
char *expand_argument (const char *str, const char *end);
char *variable_expand_string (char *line, const char *string, long length);
void install_variable_buffer (char **bufp, unsigned int *lenp);
void restore_variable_buffer (char *buf, unsigned int len);

/* function.c */
int handle_function (char **op, const char **stringp);
int pattern_matches (const char *pattern, const char *percent, const char *str);
char *subst_expand (char *o, const char *text, const char *subst,
                    const char *replace, unsigned int slen, unsigned int rlen,
                    int by_word);
char *patsubst_expand_pat (char *o, const char *text, const char *pattern,
                           const char *replace, const char *pattern_percent,
                           const char *replace_percent);
char *patsubst_expand (char *o, const char *text, char *pattern, char *replace);

/* expand.c */
char *recursively_expand_for_file (struct variable *v, struct file *file);
#define recursively_expand(v)   recursively_expand_for_file (v, NULL)

/* variable.c */
struct variable_set_list *create_new_variable_set (void);
void free_variable_set (struct variable_set_list *);
struct variable_set_list *push_new_variable_scope (void);
void pop_variable_scope (void);
void define_automatic_variables (void);
void initialize_file_variables (struct file *file, int reading);
void print_file_variables (const struct file *file);
void print_variable_set (struct variable_set *set, char *prefix);
void merge_variable_set_lists (struct variable_set_list **to_list,
                               struct variable_set_list *from_list);
struct variable *do_variable_definition (const struct floc *flocp,
                                         const char *name, const char *value,
                                         enum variable_origin origin,
                                         enum variable_flavor flavor,
                                         int target_var);
struct variable *parse_variable_definition (struct variable *v, char *line);
struct variable *try_variable_definition (const struct floc *flocp, char *line,
                                          enum variable_origin origin,
                                          int target_var);
void init_hash_global_variable_set (void);
void hash_init_function_table (void);
struct variable *lookup_variable (const char *name, unsigned int length);
struct variable *lookup_variable_in_set (const char *name, unsigned int length,
                                         const struct variable_set *set);

struct variable *define_variable_in_set (const char *name, unsigned int length,
                                         const char *value,
                                         enum variable_origin origin,
                                         int recursive,
                                         struct variable_set *set,
                                         const struct floc *flocp);

/* Define a variable in the current variable set.  */

#define define_variable(n,l,v,o,r) \
          define_variable_in_set((n),(l),(v),(o),(r),\
                                 current_variable_set_list->set,NILF)

/* Define a variable with a location in the current variable set.  */

#define define_variable_loc(n,l,v,o,r,f) \
          define_variable_in_set((n),(l),(v),(o),(r),\
                                 current_variable_set_list->set,(f))

/* Define a variable with a location in the global variable set.  */

#define define_variable_global(n,l,v,o,r,f) \
          define_variable_in_set((n),(l),(v),(o),(r),NULL,(f))

/* Define a variable in FILE's variable set.  */

#define define_variable_for_file(n,l,v,o,r,f) \
          define_variable_in_set((n),(l),(v),(o),(r),(f)->variables->set,NILF)

/* Warn that NAME is an undefined variable.  */

#define warn_undefined(n,l) do{\
                              if (warn_undefined_variables_flag) \
                                error (reading_file, \
                                       _("warning: undefined variable `%.*s'"), \
                                (int)(l), (n)); \
                              }while(0)

char **target_environment (struct file *file);

struct pattern_var *create_pattern_var (const char *target,
                                        const char *suffix);

extern int export_all_variables;

#define MAKELEVEL_NAME "MAKELEVEL"
#define MAKELEVEL_LENGTH (sizeof (MAKELEVEL_NAME) - 1)