strvec.h

   1 #ifndef STRVEC_H
   2 #define STRVEC_H
   3
   4 /**
   5  * The strvec API allows one to dynamically build and store
   6  * NULL-terminated arrays of strings. A strvec maintains the invariant that the
   7  * `items` member always points to a non-NULL array, and that the array is
   8  * always NULL-terminated at the element pointed to by `items[nr]`. 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 `strvec` manages its own memory. Any strings pushed into the
  18  * array are duplicated, and all memory is freed by strvec_clear().
  19  */
  20
  21 extern const char *empty_strvec[];
  22
  23 /**
  24  * A single array. This should be initialized by assignment from
  25  * `STRVEC_INIT`, or by calling `strvec_init`. The `items`
  26  * member contains the actual array; the `nr` member contains the
  27  * number of elements in the array, not including the terminating
  28  * NULL.
  29  */
  30 struct strvec {
  31         const char **v;
  32         size_t nr;
  33         size_t alloc;
  34 };
  35
  36 #define STRVEC_INIT { \
  37         .v = empty_strvec, \
  38 }
  39
  40 /**
  41  * Initialize an array. This is no different than assigning from
  42  * `STRVEC_INIT`.
  43  */
  44 void strvec_init(struct strvec *);
  45
  46 /* Push a copy of a string onto the end of the array. */
  47 const char *strvec_push(struct strvec *, const char *);
  48
  49 /**
  50  * Format a string and push it onto the end of the array. This is a
  51  * convenience wrapper combining `strbuf_addf` and `strvec_push`.
  52  */
  53 __attribute__((format (printf,2,3)))
  54 const char *strvec_pushf(struct strvec *, const char *fmt, ...);
  55
  56 /**
  57  * Push a list of strings onto the end of the array. The arguments
  58  * should be a list of `const char *` strings, terminated by a NULL
  59  * argument.
  60  */
  61 LAST_ARG_MUST_BE_NULL
  62 void strvec_pushl(struct strvec *, ...);
  63
  64 /* Push a null-terminated array of strings onto the end of the array. */
  65 void strvec_pushv(struct strvec *, const char **);
  66
  67 /**
  68  * Remove the final element from the array. If there are no
  69  * elements in the array, do nothing.
  70  */
  71 void strvec_pop(struct strvec *);
  72
  73 /* Splits by whitespace; does not handle quoted arguments! */
  74 void strvec_split(struct strvec *, const char *);
  75
  76 /**
  77  * Free all memory associated with the array and return it to the
  78  * initial, empty state.
  79  */
  80 void strvec_clear(struct strvec *);
  81
  82 /**
  83  * Disconnect the `items` member from the `strvec` struct and
  84  * return it. The caller is responsible for freeing the memory used
  85  * by the array, and by the strings it references. After detaching,
  86  * the `strvec` is in a reinitialized state and can be pushed
  87  * into again.
  88  */
  89 const char **strvec_detach(struct strvec *);
  90
  91 #endif /* STRVEC_H */