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tal.h (18998B)


      1 /* Licensed under BSD-MIT - see LICENSE file for details */
      2 #ifndef CCAN_TAL_H
      3 #define CCAN_TAL_H
      4 #include "../config.h"
      5 #include "../compiler.h"
      6 #include "likely.h"
      7 #include "typesafe_cb.h"
      8 #include "str.h"
      9 #include "take.h"
     10 
     11 #include <stdlib.h>
     12 #include <stdbool.h>
     13 #include <stdarg.h>
     14 
     15 /**
     16  * tal_t - convenient alias for void to mark tal pointers.
     17  *
     18  * Since any pointer can be a tal-allocated pointer, it's often
     19  * useful to use this typedef to mark them explicitly.
     20  */
     21 typedef void tal_t;
     22 
     23 /**
     24  * tal - basic allocator function
     25  * @ctx: NULL, or tal allocated object to be parent.
     26  * @type: the type to allocate.
     27  *
     28  * Allocates a specific type, with a given parent context.  The name
     29  * of the object is a string of the type, but if CCAN_TAL_DEBUG is
     30  * defined it also contains the file and line which allocated it.
     31  *
     32  * tal_count() of the return will be 1.
     33  *
     34  * Example:
     35  *    int *p = tal(NULL, int);
     36  *    *p = 1;
     37  */
     38 #define tal(ctx, type)                            \
     39     tal_label(ctx, type, TAL_LABEL(type, ""))
     40 
     41 /**
     42  * talz - zeroing allocator function
     43  * @ctx: NULL, or tal allocated object to be parent.
     44  * @type: the type to allocate.
     45  *
     46  * Equivalent to tal() followed by memset() to zero.
     47  *
     48  * Example:
     49  *    p = talz(NULL, int);
     50  *    assert(*p == 0);
     51  */
     52 #define talz(ctx, type)                            \
     53     talz_label(ctx, type, TAL_LABEL(type, ""))
     54 
     55 /**
     56  * tal_free - free a tal-allocated pointer.
     57  * @p: NULL, or tal allocated object to free.
     58  *
     59  * This calls the destructors for p (if any), then does the same for all its
     60  * children (recursively) before finally freeing the memory.  It returns
     61  * NULL, for convenience.
     62  *
     63  * Note: errno is preserved by this call, and also saved and restored
     64  * for any destructors or notifiers.
     65  *
     66  * Example:
     67  *    p = tal_free(p);
     68  */
     69 void *tal_free(const tal_t *p);
     70 
     71 /**
     72  * tal_arr - allocate an array of objects.
     73  * @ctx: NULL, or tal allocated object to be parent.
     74  * @type: the type to allocate.
     75  * @count: the number to allocate.
     76  *
     77  * tal_count() of the returned pointer will be @count.
     78  *
     79  * Example:
     80  *    p = tal_arr(NULL, int, 2);
     81  *    p[0] = 0;
     82  *    p[1] = 1;
     83  */
     84 #define tal_arr(ctx, type, count)                    \
     85     tal_arr_label(ctx, type, count, TAL_LABEL(type, "[]"))
     86 
     87 /**
     88  * tal_arrz - allocate an array of zeroed objects.
     89  * @ctx: NULL, or tal allocated object to be parent.
     90  * @type: the type to allocate.
     91  * @count: the number to allocate.
     92  *
     93  * Equivalent to tal_arr() followed by memset() to zero.
     94  *
     95  * Example:
     96  *    p = tal_arrz(NULL, int, 2);
     97  *    assert(p[0] == 0 && p[1] == 0);
     98  */
     99 #define tal_arrz(ctx, type, count) \
    100     tal_arrz_label(ctx, type, count, TAL_LABEL(type, "[]"))
    101 
    102 /**
    103  * tal_resize - enlarge or reduce a tal object.
    104  * @p: A pointer to the tal allocated array to resize.
    105  * @count: the number to allocate.
    106  *
    107  * This returns true on success (and may move *@p), or false on failure.
    108  * On success, tal_count() of *@p will be @count.
    109  *
    110  * Note: if *p is take(), it will still be take() upon return, even if it
    111  * has been moved.
    112  *
    113  * Example:
    114  *    tal_resize(&p, 100);
    115  */
    116 #define tal_resize(p, count) \
    117     tal_resize_((void **)(p), sizeof**(p), (count), false)
    118 
    119 /**
    120  * tal_resizez - enlarge or reduce a tal object; zero out extra.
    121  * @p: A pointer to the tal allocated array to resize.
    122  * @count: the number to allocate.
    123  *
    124  * This returns true on success (and may move *@p), or false on failure.
    125  *
    126  * Example:
    127  *    tal_resizez(&p, 200);
    128  */
    129 #define tal_resizez(p, count) \
    130     tal_resize_((void **)(p), sizeof**(p), (count), true)
    131 
    132 /**
    133  * tal_steal - change the parent of a tal-allocated pointer.
    134  * @ctx: The new parent.
    135  * @ptr: The tal allocated object to move, or NULL.
    136  *
    137  * This may need to perform an allocation, in which case it may fail; thus
    138  * it can return NULL, otherwise returns @ptr.  If @ptr is NULL, this function does
    139  * nothing.
    140  */
    141 #if HAVE_STATEMENT_EXPR
    142 /* Weird macro avoids gcc's 'warning: value computed is not used'. */
    143 #define tal_steal(ctx, ptr) \
    144     ({ (tal_typeof(ptr) tal_steal_((ctx),(ptr))); })
    145 #else
    146 #define tal_steal(ctx, ptr) \
    147     (tal_typeof(ptr) tal_steal_((ctx),(ptr)))
    148 #endif
    149 
    150 /**
    151  * tal_add_destructor - add a callback function when this context is destroyed.
    152  * @ptr: The tal allocated object.
    153  * @function: the function to call before it's freed.
    154  *
    155  * This is a more convenient form of tal_add_notifier(@ptr,
    156  * TAL_NOTIFY_FREE, ...), in that the function prototype takes only @ptr.
    157  *
    158  * Note that this can only fail if your allocfn fails and your errorfn returns.
    159  */
    160 #define tal_add_destructor(ptr, function)                      \
    161     tal_add_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
    162 
    163 /**
    164  * tal_del_destructor - remove a destructor callback function.
    165  * @ptr: The tal allocated object.
    166  * @function: the function to call before it's freed.
    167  *
    168  * If @function has not been successfully added as a destructor, this returns
    169  * false.  Note that if we're inside the destructor call itself, this will
    170  * return false.
    171  */
    172 #define tal_del_destructor(ptr, function)                      \
    173     tal_del_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
    174 
    175 /**
    176  * tal_add_destructor2 - add a 2-arg callback function when context is destroyed.
    177  * @ptr: The tal allocated object.
    178  * @function: the function to call before it's freed.
    179  * @arg: the extra argument to the function.
    180  *
    181  * Sometimes an extra argument is required for a destructor; this
    182  * saves the extra argument internally to avoid the caller having to
    183  * do an extra allocation.
    184  *
    185  * Note that this can only fail if your allocfn fails and your errorfn returns.
    186  */
    187 #define tal_add_destructor2(ptr, function, arg)                \
    188     tal_add_destructor2_((ptr),                    \
    189                  typesafe_cb_cast(void (*)(tal_t *, void *), \
    190                           void (*)(__typeof__(ptr), \
    191                                __typeof__(arg)), \
    192                           (function)),        \
    193                  (arg))
    194 
    195 /**
    196  * tal_del_destructor - remove a destructor callback function.
    197  * @ptr: The tal allocated object.
    198  * @function: the function to call before it's freed.
    199  *
    200  * If @function has not been successfully added as a destructor, this returns
    201  * false.  Note that if we're inside the destructor call itself, this will
    202  * return false.
    203  */
    204 #define tal_del_destructor(ptr, function)                      \
    205     tal_del_destructor_((ptr), typesafe_cb(void, void *, (function), (ptr)))
    206 
    207 /**
    208  * tal_del_destructor2 - remove 2-arg callback function.
    209  * @ptr: The tal allocated object.
    210  * @function: the function to call before it's freed.
    211  * @arg: the extra argument to the function.
    212  *
    213  * If @function has not been successfully added as a destructor with
    214  * @arg, this returns false.
    215  */
    216 #define tal_del_destructor2(ptr, function, arg)                \
    217     tal_del_destructor2_((ptr),                    \
    218                  typesafe_cb_cast(void (*)(tal_t *, void *), \
    219                           void (*)(__typeof__(ptr), \
    220                                __typeof__(arg)), \
    221                           (function)),        \
    222                  (arg))
    223 enum tal_notify_type {
    224     TAL_NOTIFY_FREE = 1,
    225     TAL_NOTIFY_STEAL = 2,
    226     TAL_NOTIFY_MOVE = 4,
    227     TAL_NOTIFY_RESIZE = 8,
    228     TAL_NOTIFY_RENAME = 16,
    229     TAL_NOTIFY_ADD_CHILD = 32,
    230     TAL_NOTIFY_DEL_CHILD = 64,
    231     TAL_NOTIFY_ADD_NOTIFIER = 128,
    232     TAL_NOTIFY_DEL_NOTIFIER = 256
    233 };
    234 
    235 /**
    236  * tal_add_notifier - add a callback function when this context changes.
    237  * @ptr: The tal allocated object, or NULL.
    238  * @types: Bitwise OR of the types the callback is interested in.
    239  * @callback: the function to call.
    240  *
    241  * Note that this can only fail if your allocfn fails and your errorfn
    242  * returns.  Also note that notifiers are not reliable in the case
    243  * where an allocation fails, as they may be called before any
    244  * allocation is actually done.
    245  *
    246  * TAL_NOTIFY_FREE is called when @ptr is freed, either directly or
    247  * because an ancestor is freed: @info is the argument to tal_free().
    248  * It is exactly equivalent to a destructor, with more information.
    249  * errno is set to the value it was at the call of tal_free().
    250  *
    251  * TAL_NOTIFY_STEAL is called when @ptr's parent changes: @info is the
    252  * new parent.
    253  *
    254  * TAL_NOTIFY_MOVE is called when @ptr is realloced (via tal_resize)
    255  * and moved.  In this case, @ptr arg here is the new memory, and
    256  * @info is the old pointer.
    257  *
    258  * TAL_NOTIFY_RESIZE is called when @ptr is realloced via tal_resize:
    259  * @info is the new size, in bytes.  If the pointer has moved,
    260  * TAL_NOTIFY_MOVE callbacks are called first.
    261  *
    262  * TAL_NOTIFY_ADD_CHILD/TAL_NOTIFY_DEL_CHILD are called when @ptr is
    263  * the context for a tal() allocating call, or a direct child is
    264  * tal_free()d: @info is the child.  Note that TAL_NOTIFY_DEL_CHILD is
    265  * not called when this context is tal_free()d: TAL_NOTIFY_FREE is
    266  * considered sufficient for that case.
    267  *
    268  * TAL_NOTIFY_ADD_NOTIFIER/TAL_NOTIFIER_DEL_NOTIFIER are called when a
    269  * notifier is added or removed (not for this notifier): @info is the
    270  * callback.  This is also called for tal_add_destructor and
    271  * tal_del_destructor.
    272  */
    273 #define tal_add_notifier(ptr, types, callback)                \
    274     tal_add_notifier_((ptr), (types),                \
    275               typesafe_cb_postargs(void, tal_t *, (callback), \
    276                            (ptr),            \
    277                            enum tal_notify_type, void *))
    278 
    279 /**
    280  * tal_del_notifier - remove a notifier callback function.
    281  * @ptr: The tal allocated object.
    282  * @callback: the function to call.
    283  */
    284 #define tal_del_notifier(ptr, callback)                    \
    285     tal_del_notifier_((ptr),                    \
    286               typesafe_cb_postargs(void, void *, (callback), \
    287                            (ptr),            \
    288                            enum tal_notify_type, void *), \
    289               false, NULL)
    290 
    291 /**
    292  * tal_set_name - attach a name to a tal pointer.
    293  * @ptr: The tal allocated object.
    294  * @name: The name to use.
    295  *
    296  * The name is copied, unless we're certain it's a string literal.
    297  */
    298 #define tal_set_name(ptr, name)                      \
    299     tal_set_name_((ptr), (name), TAL_IS_LITERAL(name))
    300 
    301 /**
    302  * tal_name - get the name for a tal pointer.
    303  * @ptr: The tal allocated object.
    304  *
    305  * Returns NULL if no name has been set.
    306  */
    307 const char *tal_name(const tal_t *ptr);
    308 
    309 /**
    310  * tal_count - get the count of objects in a tal object.
    311  * @ptr: The tal allocated object (or NULL)
    312  *
    313  * Returns 0 if @ptr is NULL.  Note that if the allocation was done as a
    314  * different type to @ptr, the result may not match the @count argument
    315  * (or implied 1) of that allocation!
    316  */
    317 #define tal_count(p) (tal_bytelen(p) / sizeof(*p))
    318 
    319 /**
    320  * tal_bytelen - get the count of bytes in a tal object.
    321  * @ptr: The tal allocated object (or NULL)
    322  *
    323  * Returns 0 if @ptr is NULL.
    324  */
    325 size_t tal_bytelen(const tal_t *ptr);
    326 
    327 /**
    328  * tal_first - get the first immediate tal object child.
    329  * @root: The tal allocated object to start with, or NULL.
    330  *
    331  * Returns NULL if there are no children.
    332  */
    333 tal_t *tal_first(const tal_t *root);
    334 
    335 /**
    336  * tal_next - get the next immediate tal object child.
    337  * @prev: The return value from tal_first or tal_next.
    338  *
    339  * Returns NULL if there are no more immediate children.  This should be safe to
    340  * call on an altering tree unless @prev is no longer valid.
    341  */
    342 tal_t *tal_next(const tal_t *prev);
    343 
    344 /**
    345  * tal_parent - get the parent of a tal object.
    346  * @ctx: The tal allocated object.
    347  *
    348  * Returns the parent, which may be NULL.  Returns NULL if @ctx is NULL.
    349  */
    350 tal_t *tal_parent(const tal_t *ctx);
    351 
    352 /**
    353  * tal_dup - duplicate an object.
    354  * @ctx: The tal allocated object to be parent of the result (may be NULL).
    355  * @type: the type (should match type of @p!)
    356  * @p: the object to copy (or reparented if take()).  Must not be NULL.
    357  */
    358 #define tal_dup(ctx, type, p)                    \
    359     tal_dup_label(ctx, type, p, TAL_LABEL(type, ""), false)
    360 
    361 /**
    362  * tal_dup_or_null - duplicate an object, or just pass NULL.
    363  * @ctx: The tal allocated object to be parent of the result (may be NULL).
    364  * @type: the type (should match type of @p!)
    365  * @p: the object to copy (or reparented if take())
    366  *
    367  * if @p is NULL, just return NULL, otherwise to tal_dup().
    368  */
    369 #define tal_dup_or_null(ctx, type, p)                    \
    370     tal_dup_label(ctx, type, p, TAL_LABEL(type, ""), true)
    371 
    372 /**
    373  * tal_dup_arr - duplicate an array.
    374  * @ctx: The tal allocated object to be parent of the result (may be NULL).
    375  * @type: the type (should match type of @p!)
    376  * @p: the array to copy (or resized & reparented if take())
    377  * @n: the number of sizeof(type) entries to copy.
    378  * @extra: the number of extra sizeof(type) entries to allocate.
    379  */
    380 #define tal_dup_arr(ctx, type, p, n, extra)            \
    381     tal_dup_arr_label(ctx, type, p, n, extra, TAL_LABEL(type, "[]"))
    382 
    383 
    384 /**
    385  * tal_dup_arr - duplicate a tal array.
    386  * @ctx: The tal allocated object to be parent of the result (may be NULL).
    387  * @type: the type (should match type of @p!)
    388  * @p: the tal array to copy (or resized & reparented if take())
    389  *
    390  * The common case of duplicating an entire tal array.
    391  */
    392 #define tal_dup_talarr(ctx, type, p)                    \
    393     ((type *)tal_dup_talarr_((ctx), tal_typechk_(p, type *),    \
    394                  TAL_LABEL(type, "[]")))
    395 /* Lower-level interfaces, where you want to supply your own label string. */
    396 #define tal_label(ctx, type, label)                        \
    397     ((type *)tal_alloc_((ctx), sizeof(type), false, label))
    398 #define talz_label(ctx, type, label)                        \
    399     ((type *)tal_alloc_((ctx), sizeof(type), true, label))
    400 #define tal_arr_label(ctx, type, count, label)                    \
    401     ((type *)tal_alloc_arr_((ctx), sizeof(type), (count), false, label))
    402 #define tal_arrz_label(ctx, type, count, label)                    \
    403     ((type *)tal_alloc_arr_((ctx), sizeof(type), (count), true, label))
    404 #define tal_dup_label(ctx, type, p, label, nullok)            \
    405     ((type *)tal_dup_((ctx), tal_typechk_(p, type *),    \
    406               sizeof(type), 1, 0, nullok,        \
    407               label))
    408 #define tal_dup_arr_label(ctx, type, p, n, extra, label)    \
    409     ((type *)tal_dup_((ctx), tal_typechk_(p, type *),    \
    410               sizeof(type), (n), (extra), false,    \
    411               label))
    412 
    413 /**
    414  * tal_set_backend - set the allocation or error functions to use
    415  * @alloc_fn: allocator or NULL (default is malloc)
    416  * @resize_fn: re-allocator or NULL (default is realloc)
    417  * @free_fn: free function or NULL (default is free)
    418  * @error_fn: called on errors or NULL (default is abort)
    419  *
    420  * The defaults are set up so tal functions never return NULL, but you
    421  * can override error_fn to change that.  error_fn can return, and is
    422  * called if alloc_fn or resize_fn fail.
    423  *
    424  * If any parameter is NULL, that function is unchanged.
    425  */
    426 void tal_set_backend(void *(*alloc_fn)(size_t size),
    427              void *(*resize_fn)(void *, size_t size),
    428              void (*free_fn)(void *),
    429              void (*error_fn)(const char *msg));
    430 
    431 /**
    432  * tal_expand - expand a tal array with contents.
    433  * @a1p: a pointer to the tal array to expand.
    434  * @a2: the second array (can be take()).
    435  * @num2: the number of elements in the second array.
    436  *
    437  * Note that *@a1 and @a2 should be the same type.  tal_count(@a1) will
    438  * be increased by @num2.
    439  *
    440  * Example:
    441  *    int *arr1 = tal_arrz(NULL, int, 2);
    442  *    int arr2[2] = { 1, 3 };
    443  *
    444  *    tal_expand(&arr1, arr2, 2);
    445  *    assert(tal_count(arr1) == 4);
    446  *    assert(arr1[2] == 1);
    447  *    assert(arr1[3] == 3);
    448  */
    449 #define tal_expand(a1p, a2, num2)                \
    450     tal_expand_((void **)(a1p), (a2), sizeof**(a1p),    \
    451             (num2) + 0*sizeof(*(a1p) == (a2)))
    452 
    453 /**
    454  * tal_cleanup - remove pointers from NULL node
    455  *
    456  * Internally, tal keeps a list of nodes allocated from @ctx NULL; this
    457  * prevents valgrind from noticing memory leaks.  This re-initializes
    458  * that list to empty.
    459  *
    460  * It also calls take_cleanup() for you.
    461  */
    462 void tal_cleanup(void);
    463 
    464 
    465 /**
    466  * tal_check - sanity check a tal context and its children.
    467  * @ctx: a tal context, or NULL.
    468  * @errorstr: a string to prepend calls to error_fn, or NULL.
    469  *
    470  * This sanity-checks a tal tree (unless NDEBUG is defined, in which case
    471  * it simply returns true).  If errorstr is not null, error_fn is called
    472  * when a problem is found, otherwise it is not.
    473  *
    474  * See also:
    475  *    tal_set_backend()
    476  */
    477 bool tal_check(const tal_t *ctx, const char *errorstr);
    478 
    479 #ifdef CCAN_TAL_DEBUG
    480 /**
    481  * tal_dump - dump entire tal tree to stderr.
    482  *
    483  * This is a helper for debugging tal itself, which dumps all the tal internal
    484  * state.
    485  */
    486 void tal_dump(void);
    487 #endif
    488 
    489 /* Internal support functions */
    490 #ifndef TAL_LABEL
    491 #ifdef CCAN_TAL_NO_LABELS
    492 #define TAL_LABEL(type, arr) NULL
    493 #else
    494 #ifdef CCAN_TAL_DEBUG
    495 #define TAL_LABEL(type, arr) \
    496     __FILE__ ":" stringify(__LINE__) ":" stringify(type) arr
    497 #else
    498 #define TAL_LABEL(type, arr) stringify(type) arr
    499 #endif /* CCAN_TAL_DEBUG */
    500 #endif
    501 #endif
    502 
    503 #if HAVE_BUILTIN_CONSTANT_P
    504 #define TAL_IS_LITERAL(str) __builtin_constant_p(str)
    505 #else
    506 #define TAL_IS_LITERAL(str) (sizeof(&*(str)) != sizeof(char *))
    507 #endif
    508 
    509 bool tal_set_name_(tal_t *ctx, const char *name, bool literal);
    510 
    511 #if HAVE_TYPEOF
    512 #define tal_typeof(ptr) (__typeof__(ptr))
    513 #if HAVE_STATEMENT_EXPR
    514 /* Careful: ptr can be const foo *, ptype is foo *.  Also, ptr could
    515  * be an array, eg "hello". */
    516 #define tal_typechk_(ptr, ptype) ({ __typeof__((ptr)+0) _p = (ptype)(ptr); _p; })
    517 #else
    518 #define tal_typechk_(ptr, ptype) (ptr)
    519 #endif
    520 #else /* !HAVE_TYPEOF */
    521 #define tal_typeof(ptr)
    522 #define tal_typechk_(ptr, ptype) (ptr)
    523 #endif
    524 
    525 void *tal_alloc_(const tal_t *ctx, size_t bytes, bool clear, const char *label);
    526 void *tal_alloc_arr_(const tal_t *ctx, size_t bytes, size_t count, bool clear,
    527              const char *label);
    528 
    529 void *tal_dup_(const tal_t *ctx, const void *p TAKES, size_t size,
    530            size_t n, size_t extra, bool nullok, const char *label);
    531 void *tal_dup_talarr_(const tal_t *ctx, const tal_t *src TAKES,
    532               const char *label);
    533 
    534 tal_t *tal_steal_(const tal_t *new_parent, const tal_t *t);
    535 
    536 bool tal_resize_(tal_t **ctxp, size_t size, size_t count, bool clear);
    537 bool tal_expand_(tal_t **ctxp, const void *src TAKES, size_t size, size_t count);
    538 
    539 bool tal_add_destructor_(const tal_t *ctx, void (*destroy)(void *me));
    540 bool tal_add_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
    541               void *arg);
    542 bool tal_del_destructor_(const tal_t *ctx, void (*destroy)(void *me));
    543 bool tal_del_destructor2_(const tal_t *ctx, void (*destroy)(void *me, void *arg),
    544               void *arg);
    545 
    546 bool tal_add_notifier_(const tal_t *ctx, enum tal_notify_type types,
    547                void (*notify)(tal_t *ctx, enum tal_notify_type,
    548                       void *info));
    549 bool tal_del_notifier_(const tal_t *ctx,
    550                void (*notify)(tal_t *ctx, enum tal_notify_type,
    551                       void *info),
    552                bool match_extra_arg, void *arg);
    553 #endif /* CCAN_TAL_H */