argv-array.h

   1 #ifndef ARGV_ARRAY_H
   2 #define ARGV_ARRAY_H
   3
   4 /**
   5  * The argv-array API allows one to dynamically build and store
   6  * NULL-terminated lists.  An argv-array maintains the invariant that the
   7  * `argv` member always points to a non-NULL array, and that the array is
   8  * always NULL-terminated at the element pointed to by `argv[argc]`. This
   9  * makes the result suitable for passing to functions expecting to receive
  10  * argv from main().
  11  *
  12  * The string-list API (documented in string-list.h) is similar, but cannot be
  13  * used for these purposes; instead of storing a straight string pointer,
  14  * it contains an item structure with a `util` field that is not compatible
  15  * with the traditional argv interface.
  16  *
  17  * Each `argv_array` manages its own memory. Any strings pushed into the
  18  * array are duplicated, and all memory is freed by argv_array_clear().
  19  */
  20
  21 extern const char *empty_argv[];
  22
  23 /**
  24  * A single array. This should be initialized by assignment from
  25  * `ARGV_ARRAY_INIT`, or by calling `argv_array_init`. The `argv`
  26  * member contains the actual array; the `argc` member contains the
  27  * number of elements in the array, not including the terminating
  28  * NULL.
  29  */
  30 struct argv_array {
  31         const char **argv;
  32         int argc;
  33         int alloc;
  34 };
  35
  36 #define ARGV_ARRAY_INIT { empty_argv, 0, 0 }
  37
  38 /**
  39  * Initialize an array. This is no different than assigning from
  40  * `ARGV_ARRAY_INIT`.
  41  */
  42 void argv_array_init(struct argv_array *);
  43
  44 /* Push a copy of a string onto the end of the array. */
  45 const char *argv_array_push(struct argv_array *, const char *);
  46
  47 /**
  48  * Format a string and push it onto the end of the array. This is a
  49  * convenience wrapper combining `strbuf_addf` and `argv_array_push`.
  50  */
  51 __attribute__((format (printf,2,3)))
  52 const char *argv_array_pushf(struct argv_array *, const char *fmt, ...);
  53
  54 /**
  55  * Push a list of strings onto the end of the array. The arguments
  56  * should be a list of `const char *` strings, terminated by a NULL
  57  * argument.
  58  */
  59 LAST_ARG_MUST_BE_NULL
  60 void argv_array_pushl(struct argv_array *, ...);
  61
  62 /* Push a null-terminated array of strings onto the end of the array. */
  63 void argv_array_pushv(struct argv_array *, const char **);
  64
  65 /**
  66  * Remove the final element from the array. If there are no
  67  * elements in the array, do nothing.
  68  */
  69 void argv_array_pop(struct argv_array *);
  70
  71 /* Splits by whitespace; does not handle quoted arguments! */
  72 void argv_array_split(struct argv_array *, const char *);
  73
  74 /**
  75  * Free all memory associated with the array and return it to the
  76  * initial, empty state.
  77  */
  78 void argv_array_clear(struct argv_array *);
  79
  80 /**
  81  * Disconnect the `argv` member from the `argv_array` struct and
  82  * return it. The caller is responsible for freeing the memory used
  83  * by the array, and by the strings it references. After detaching,
  84  * the `argv_array` is in a reinitialized state and can be pushed
  85  * into again.
  86  */
  87 const char **argv_array_detach(struct argv_array *);
  88
  89 #endif /* ARGV_ARRAY_H */