/* Internals of variables for GNU Make.
Copyright (C) 1988, 89, 90, 91, 92, 93, 94 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 2, 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 GNU Make; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "make.h"
#include "commands.h"
#include "variable.h"
#include "dep.h"
#include "file.h"

/* Hash table of all global variable definitions.  */

#ifndef	VARIABLE_BUCKETS
#define VARIABLE_BUCKETS		523
#endif
#ifndef	PERFILE_VARIABLE_BUCKETS
#define	PERFILE_VARIABLE_BUCKETS	23
#endif
#ifndef	SMALL_SCOPE_VARIABLE_BUCKETS
#define	SMALL_SCOPE_VARIABLE_BUCKETS	13
#endif
static struct variable *variable_table[VARIABLE_BUCKETS];
static struct variable_set global_variable_set
  = { variable_table, VARIABLE_BUCKETS };
static struct variable_set_list global_setlist
  = { 0, &global_variable_set };
struct variable_set_list *current_variable_set_list = &global_setlist;

/* Implement variables.  */

/* Define variable named NAME with value VALUE in SET.  VALUE is copied.
   LENGTH is the length of NAME, which does not need to be null-terminated.
   ORIGIN specifies the origin of the variable (makefile, command line
   or environment).
   If RECURSIVE is nonzero a flag is set in the variable saying
   that it should be recursively re-expanded.  */

static struct variable *
define_variable_in_set (name, length, value, origin, recursive, set)
     char *name;
     unsigned int length;
     char *value;
     enum variable_origin origin;
     int recursive;
     struct variable_set *set;
{
  register unsigned int i;
  register unsigned int hashval;
  register struct variable *v;

  hashval = 0;
  for (i = 0; i < length; ++i)
    HASH (hashval, name[i]);
  hashval %= set->buckets;

  for (v = set->table[hashval]; v != 0; v = v->next)
    if (*v->name == *name
	&& !strncmp (v->name + 1, name + 1, length - 1)
	&& v->name[length] == '\0')
      break;

  if (env_overrides && origin == o_env)
    origin = o_env_override;

  if (v != 0)
    {
      if (env_overrides && v->origin == o_env)
	/* V came from in the environment.  Since it was defined
	   before the switches were parsed, it wasn't affected by -e.  */
	v->origin = o_env_override;

      /* A variable of this name is already defined.
	 If the old definition is from a stronger source
	 than this one, don't redefine it.  */
      if ((int) origin >= (int) v->origin)
	{
	  if (v->value != 0)
	    free (v->value);
	  v->value = savestring (value, strlen (value));
	  v->origin = origin;
	  v->recursive = recursive;
	}
      return v;
    }

  /* Create a new variable definition and add it to the hash table.  */

  v = (struct variable *) xmalloc (sizeof (struct variable));
  v->name = savestring (name, length);
  v->value = savestring (value, strlen (value));
  v->origin = origin;
  v->recursive = recursive;
  v->expanding = 0;
  v->export = v_default;
  v->next = set->table[hashval];
  set->table[hashval] = v;
  return v;
}

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

struct variable *
define_variable (name, length, value, origin, recursive)
     char *name;
     unsigned int length;
     char *value;
     enum variable_origin origin;
     int recursive;
{
  return define_variable_in_set (name, length, value, origin, recursive,
				 current_variable_set_list->set);
}

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

struct variable *
define_variable_for_file (name, length, value, origin, recursive, file)
     char *name;
     unsigned int length;
     char *value;
     enum variable_origin origin;
     int recursive;
     struct file *file;
{
  return define_variable_in_set (name, length, value, origin, recursive,
				 file->variables->set);
}

/* Lookup a variable whose name is a string starting at NAME
   and with LENGTH chars.  NAME need not be null-terminated.
   Returns address of the `struct variable' containing all info
   on the variable, or nil if no such variable is defined.  */

struct variable *
lookup_variable (name, length)
     char *name;
     unsigned int length;
{
  register struct variable_set_list *setlist;

  register unsigned int i;
  register unsigned int rawhash = 0;

  for (i = 0; i < length; ++i)
    HASH (rawhash, name[i]);

  for (setlist = current_variable_set_list;
       setlist != 0; setlist = setlist->next)
    {
      register struct variable_set *set = setlist->set;
      register unsigned int hashval = rawhash % set->buckets;
      register struct variable *v;

      for (v = set->table[hashval]; v != 0; v = v->next)
	if (*v->name == *name
	    && !strncmp (v->name + 1, name + 1, length - 1)
	    && v->name[length] == 0)
	  return v;
    }

  return 0;
}

/* Initialize FILE's variable set list.  If FILE already has a variable set
   list, the topmost variable set is left intact, but the the rest of the
   chain is replaced with FILE->parent's setlist.  */

void
initialize_file_variables (file)
     struct file *file;
{
  register struct variable_set_list *l = file->variables;
  if (l == 0)
    {
      l = (struct variable_set_list *)
	xmalloc (sizeof (struct variable_set_list));
      l->set = (struct variable_set *) xmalloc (sizeof (struct variable_set));
      l->set->buckets = PERFILE_VARIABLE_BUCKETS;
      l->set->table = (struct variable **)
	xmalloc (l->set->buckets * sizeof (struct variable *));
      bzero ((char *) l->set->table,
	     l->set->buckets * sizeof (struct variable *));
      file->variables = l;
    }

  if (file->parent == 0)
    l->next = &global_setlist;
  else
    {
      if (file->parent->variables == 0)
	initialize_file_variables (file->parent);
      l->next = file->parent->variables;
    }
}

/* Pop the top set off the current variable set list,
   and free all its storage.  */

void
pop_variable_scope ()
{
  register struct variable_set_list *setlist = current_variable_set_list;
  register struct variable_set *set = setlist->set;
  register unsigned int i;

  current_variable_set_list = setlist->next;
  free ((char *) setlist);

  for (i = 0; i < set->buckets; ++i)
    {
      register struct variable *next = set->table[i];
      while (next != 0)
	{
	  register struct variable *v = next;
	  next = v->next;

	  free (v->name);
	  free ((char *) v);
	}
    }
  free ((char *) set->table);
  free ((char *) set);
}

/* Create a new variable set and push it on the current setlist.  */

void
push_new_variable_scope ()
{
  register struct variable_set_list *setlist;
  register struct variable_set *set;

  set = (struct variable_set *) xmalloc (sizeof (struct variable_set));
  set->buckets = SMALL_SCOPE_VARIABLE_BUCKETS;
  set->table = (struct variable **)
    xmalloc (set->buckets * sizeof (struct variable *));
  bzero ((char *) set->table, set->buckets * sizeof (struct variable *));

  setlist = (struct variable_set_list *)
    xmalloc (sizeof (struct variable_set_list));
  setlist->set = set;
  setlist->next = current_variable_set_list;
  current_variable_set_list = setlist;
}

/* Merge SET1 into SET0, freeing unused storage in SET1.  */

static void
merge_variable_sets (set0, set1)
     struct variable_set *set0, *set1;
{
  register unsigned int bucket1;

  for (bucket1 = 0; bucket1 < set1->buckets; ++bucket1)
    {
      register struct variable *v1 = set1->table[bucket1];
      while (v1 != 0)
	{
	  struct variable *next = v1->next;
	  unsigned int bucket0;
	  register struct variable *v0;

	  if (set1->buckets >= set0->buckets)
	    bucket0 = bucket1;
	  else
	    {
	      register char *n;
	      bucket0 = 0;
	      for (n = v1->name; *n != '\0'; ++n)
		HASH (bucket0, *n);
	    }
	  bucket0 %= set0->buckets;

	  for (v0 = set0->table[bucket0]; v0 != 0; v0 = v0->next)
	    if (streq (v0->name, v1->name))
	      break;

	  if (v0 == 0)
	    {
	      /* There is no variable in SET0 with the same name.  */
	      v1->next = set0->table[bucket0];
	      set0->table[bucket0] = v1;
	    }
	  else
	    {
	      /* The same variable exists in both sets.
		 SET0 takes precedence.  */
	      free (v1->value);
	      free ((char *) v1);
	    }

	  v1 = next;
	}
    }
}

/* Merge SETLIST1 into SETLIST0, freeing unused storage in SETLIST1.  */

void
merge_variable_set_lists (setlist0, setlist1)
     struct variable_set_list **setlist0, *setlist1;
{
  register struct variable_set_list *list0 = *setlist0;
  struct variable_set_list *last0 = 0;

  while (setlist1 != 0 && list0 != 0)
    {
      struct variable_set_list *next = setlist1;
      setlist1 = setlist1->next;

      merge_variable_sets (list0->set, next->set);

      free ((char *) next);

      last0 = list0;
      list0 = list0->next;
    }

  if (setlist1 != 0)
    {
      if (last0 == 0)
	*setlist0 = setlist1;
      else
	last0->next = setlist1;
    }
}

/* Define the automatic variables, and record the addresses
   of their structures so we can change their values quickly.  */

void
define_automatic_variables ()
{
  extern char default_shell[];
  register struct variable *v;
  char buf[200];

  sprintf (buf, "%u", makelevel);
  (void) define_variable ("MAKELEVEL", 9, buf, o_env, 0);

  sprintf (buf, "%s%s%s",
	   version_string,
	   (remote_description == 0 || remote_description[0] == '\0')
	   ? "" : "-",
	   (remote_description == 0 || remote_description[0] == '\0')
	   ? "" : remote_description);
  (void) define_variable ("MAKE_VERSION", 12, buf, o_default, 0);

  
  /* This won't override any definition, but it
     will provide one if there isn't one there.  */
  v = define_variable ("SHELL", 5, default_shell, o_default, 0);
  v->export = v_export;		/* Always export SHELL.  */

  /* Don't let SHELL come from the environment.  */
  if (*v->value == '\0' || v->origin == o_env || v->origin == o_env_override)
    {
      free (v->value);
      v->origin = o_file;
      v->value = savestring (default_shell, strlen (default_shell));
    }

  /* Make sure MAKEFILES gets exported if it is set.  */
  v = define_variable ("MAKEFILES", 9, "", o_default, 0);
  v->export = v_ifset;

  /* Define the magic D and F variables in terms of
     the automatic variables they are variations of.  */

  define_variable ("@D", 2, "$(patsubst %/,%,$(dir $@))", o_automatic, 1);
  define_variable ("%D", 2, "$(patsubst %/,%,$(dir $%))", o_automatic, 1);
  define_variable ("*D", 2, "$(patsubst %/,%,$(dir $*))", o_automatic, 1);
  define_variable ("<D", 2, "$(patsubst %/,%,$(dir $<))", o_automatic, 1);
  define_variable ("?D", 2, "$(patsubst %/,%,$(dir $?))", o_automatic, 1);
  define_variable ("^D", 2, "$(patsubst %/,%,$(dir $^))", o_automatic, 1);
  define_variable ("+D", 2, "$(patsubst %/,%,$(dir $+))", o_automatic, 1);
  define_variable ("@F", 2, "$(notdir $@)", o_automatic, 1);
  define_variable ("%F", 2, "$(notdir $%)", o_automatic, 1);
  define_variable ("*F", 2, "$(notdir $*)", o_automatic, 1);
  define_variable ("<F", 2, "$(notdir $<)", o_automatic, 1);
  define_variable ("?F", 2, "$(notdir $?)", o_automatic, 1);
  define_variable ("^F", 2, "$(notdir $^)", o_automatic, 1);
  define_variable ("+F", 2, "$(notdir $+)", o_automatic, 1);
}

int export_all_variables;

/* Create a new environment for FILE's commands.
   If FILE is nil, this is for the `shell' function.
   The child's MAKELEVEL variable is incremented.  */

char **
target_environment (file)
     struct file *file;
{
  struct variable_set_list *set_list;
  register struct variable_set_list *s;
  struct variable_bucket
    {
      struct variable_bucket *next;
      struct variable *variable;
    };
  struct variable_bucket **table;
  unsigned int buckets;
  register unsigned int i;
  register unsigned nvariables;
  char **result;
  unsigned int mklev_hash;

  if (file == 0)
    set_list = current_variable_set_list;
  else
    set_list = file->variables;

  /* Find the lowest number of buckets in any set in the list.  */
  s = set_list;
  buckets = s->set->buckets;
  for (s = s->next; s != 0; s = s->next)
    if (s->set->buckets < buckets)
      buckets = s->set->buckets;

  /* Find the hash value of the bucket `MAKELEVEL' will fall into.  */
  {
    char *p = "MAKELEVEL";
    mklev_hash = 0;
    while (*p != '\0')
      HASH (mklev_hash, *p++);
  }

  /* Temporarily allocate a table with that many buckets.  */
  table = (struct variable_bucket **)
    alloca (buckets * sizeof (struct variable_bucket *));
  bzero ((char *) table, buckets * sizeof (struct variable_bucket *));

  /* Run through all the variable sets in the list,
     accumulating variables in TABLE.  */
  nvariables = 0;
  for (s = set_list; s != 0; s = s->next)
    {
      register struct variable_set *set = s->set;
      for (i = 0; i < set->buckets; ++i)
	{
	  register struct variable *v;
	  for (v = set->table[i]; v != 0; v = v->next)
	    {
	      unsigned int j = i % buckets;
	      register struct variable_bucket *ov;
	      register char *p = v->name;

	      if (i == mklev_hash % set->buckets
		  && streq (v->name, "MAKELEVEL"))
		/* Don't include MAKELEVEL because it will be
		   added specially at the end.  */
		continue;

	      switch (v->export)
		{
		case v_default:
		  if (v->origin == o_default || v->origin == o_automatic)
		    /* Only export default variables by explicit request.  */
		    continue;

		  if (! export_all_variables
		      && v->origin != o_command
		      && v->origin != o_env && v->origin != o_env_override)
		    continue;

		  if (*p != '_' && (*p < 'A' || *p > 'Z')
		      && (*p < 'a' || *p > 'z'))
		    continue;
		  for (++p; *p != '\0'; ++p)
		    if (*p != '_' && (*p < 'a' || *p > 'z')
			&& (*p < 'A' || *p > 'Z') && (*p < '0' || *p > '9'))
		      break;
		  if (*p != '\0')
		    continue;

		case v_export:
		  break;

		case v_noexport:
		  continue;

		case v_ifset:
		  if (v->origin == o_default)
		    continue;
		  break;
		}

	      for (ov = table[j]; ov != 0; ov = ov->next)
		if (streq (v->name, ov->variable->name))
		  break;
	      if (ov == 0)
		{
		  register struct variable_bucket *entry;
		  entry = (struct variable_bucket *)
		    alloca (sizeof (struct variable_bucket));
		  entry->next = table[j];
		  entry->variable = v;
		  table[j] = entry;
		  ++nvariables;
		}
	    }
	}
    }

  result = (char **) xmalloc ((nvariables + 2) * sizeof (char *));
  nvariables = 0;
  for (i = 0; i < buckets; ++i)
    {
      register struct variable_bucket *b;
      for (b = table[i]; b != 0; b = b->next)
	{
	  register struct variable *v = b->variable;
	  /* If V is recursively expanded and didn't come from the environment,
	     expand its value.  If it came from the environment, it should
	     go back into the environment unchanged.  */
	  if (v->recursive
	      && v->origin != o_env && v->origin != o_env_override)
	    {
	      char *value = recursively_expand (v);
	      result[nvariables++] = concat (v->name, "=", value);
	      free (value);
	    }
	  else
	    result[nvariables++] = concat (v->name, "=", v->value);
	}
    }
  result[nvariables] = (char *) xmalloc (100);
  (void) sprintf (result[nvariables], "MAKELEVEL=%u", makelevel + 1);
  result[++nvariables] = 0;

  return result;
}

/* Try to interpret LINE (a null-terminated string) as a variable definition.

   ORIGIN may be o_file, o_override, o_env, o_env_override,
   or o_command specifying that the variable definition comes
   from a makefile, an override directive, the environment with
   or without the -e switch, or the command line.

   A variable definition has the form "name = value" or "name := value".
   Any whitespace around the "=" or ":=" is removed.  The first form
   defines a variable that is recursively re-evaluated.  The second form
   defines a variable whose value is variable-expanded at the time of
   definition and then is evaluated only once at the time of expansion.

   If a variable was defined, a pointer to its `struct variable' is returned.
   If not, NULL is returned.  */

struct variable *
try_variable_definition (filename, lineno, line, origin)
     char *filename;
     unsigned int lineno;
     char *line;
     enum variable_origin origin;
{
  register int c;
  register char *p = line;
  register char *beg;
  register char *end;
  enum { bogus, simple, recursive, append } flavor = bogus;
  char *name, *expanded_name, *value;
  struct variable *v;

  while (1)
    {
      c = *p++;
      if (c == '\0' || c == '#')
	return 0;
      if (c == '=')
	{
	  end = p - 1;
	  flavor = recursive;
	  break;
	}
      else if (c == ':')
	if (*p == '=')
	  {
	    end = p++ - 1;
	    flavor = simple;
	    break;
	  }
	else
	  /* A colon other than := is a rule line, not a variable defn.  */
	  return 0;
      else if (c == '+' && *p == '=')
	{
	  end = p++ - 1;
	  flavor = append;
	  break;
	}
    }

  beg = next_token (line);
  while (end > beg && isblank (end[-1]))
    --end;
  p = next_token (p);

  /* Expand the name, so "$(foo)bar = baz" works.  */
  name = (char *) alloca (end - beg + 1);
  bcopy (beg, name, end - beg);
  name[end - beg] = '\0';
  expanded_name = allocated_variable_expand (name);

  if (expanded_name[0] == '\0')
    {
      if (filename == 0)
	fatal ("empty variable name");
      else
	makefile_fatal (filename, lineno, "empty variable name");
    }

  /* Calculate the variable's new value in VALUE.  */

  switch (flavor)
    {
    case bogus:
      /* Should not be possible.  */
      abort ();
      return 0;
    case simple:
      /* A simple variable definition "var := value".  Expand the value.  */
      value = variable_expand (p);
      break;
    case recursive:
      /* A recursive variable definition "var = value".
	 The value is used verbatim.  */
      value = p;
      break;
    case append:
      /* An appending variable definition "var += value".
	 Extract the old value and append the new one.  */
      v = lookup_variable (expanded_name, strlen (expanded_name));
      if (v == 0)
	{
	  /* There was no old value.
	     This becomes a normal recursive definition.  */
	  value = p;
	  flavor = recursive;
	}
      else
	{
	  /* Paste the old and new values together in VALUE.  */

	  unsigned int oldlen, newlen;

	  if (v->recursive)
	    /* The previous definition of the variable was recursive.
	       The new value comes from the unexpanded old and new values.  */
	    flavor = recursive;
	  else
	    /* The previous definition of the variable was simple.
	       The new value comes from the old value, which was expanded
	       when it was set; and from the expanded new value.  */
	    p = variable_expand (p);

	  oldlen = strlen (v->value);
	  newlen = strlen (p);
	  value = (char *) alloca (oldlen + 1 + newlen + 1);
	  bcopy (v->value, value, oldlen);
	  value[oldlen] = ' ';
	  bcopy (p, &value[oldlen + 1], newlen + 1);
	}
    }

  v = define_variable (expanded_name, strlen (expanded_name),
		       value, origin, flavor == recursive);

  free (expanded_name);

  return v;
}

/* Print information for variable V, prefixing it with PREFIX.  */

static void
print_variable (v, prefix)
     register struct variable *v;
     char *prefix;
{
  char *origin;

  switch (v->origin)
    {
    case o_default:
      origin = "default";
      break;
    case o_env:
      origin = "environment";
      break;
    case o_file:
      origin = "makefile";
      break;
    case o_env_override:
      origin = "environment under -e";
      break;
    case o_command:
      origin = "command line";
      break;
    case o_override:
      origin = "`override' directive";
      break;
    case o_automatic:
      origin = "automatic";
      break;
    case o_invalid:
    default:
      abort ();
      break;
    }
  printf ("# %s\n", origin);

  fputs (prefix, stdout);

  /* Is this a `define'?  */
  if (v->recursive && index (v->value, '\n') != 0)
    printf ("define %s\n%s\nendef\n", v->name, v->value);
  else
    {
      register char *p;

      printf ("%s %s= ", v->name, v->recursive ? "" : ":");

      /* Check if the value is just whitespace.  */
      p = next_token (v->value);
      if (p != v->value && *p == '\0')
	/* All whitespace.  */
	printf ("$(subst ,,%s)", v->value);
      else if (v->recursive)
	fputs (v->value, stdout);
      else
	/* Double up dollar signs.  */
	for (p = v->value; *p != '\0'; ++p)
	  {
	    if (*p == '$')
	      putchar ('$');
	    putchar (*p);
	  }
      putchar ('\n');
    }
}


/* Print all the variables in SET.  PREFIX is printed before
   the actual variable definitions (everything else is comments).  */

static void
print_variable_set (set, prefix)
     register struct variable_set *set;
     char *prefix;
{
  register unsigned int i, nvariables, per_bucket;
  register struct variable *v;

  per_bucket = nvariables = 0;
  for (i = 0; i < set->buckets; ++i)
    {
      register unsigned int this_bucket = 0;

      for (v = set->table[i]; v != 0; v = v->next)
	{
	  ++this_bucket;
	  print_variable (v, prefix);
	}

      nvariables += this_bucket;
      if (this_bucket > per_bucket)
	per_bucket = this_bucket;
    }

  if (nvariables == 0)
    puts ("# No variables.");
  else
    {
      printf ("# %u variables in %u hash buckets.\n",
	      nvariables, set->buckets);
#ifndef	NO_FLOAT
      printf ("# average of %.1f variables per bucket, \
max %u in one bucket.\n",
	      (double) nvariables / (double) set->buckets,
	      per_bucket);
#endif
    }
}


/* Print the data base of variables.  */

void
print_variable_data_base ()
{
  puts ("\n# Variables\n");

  print_variable_set (&global_variable_set, "");
}


/* Print all the local variables of FILE.  */

void
print_file_variables (file)
     struct file *file;
{
  if (file->variables != 0)
    print_variable_set (file->variables->set, "# ");
}