kernel/git - git - PowerEL Git System

Author	SHA1	Message	Date
Junio C Hamano	862e730ec1	commit-slab: introduce slabname##_peek() function There is no API to ask "Does this commit have associated data in slab?". If an application wants to (1) parse just a few commits at the beginning of a process, (2) store data for only these commits, and then (3) start processing many commits, taking into account the data stored (for a few of them) in the slab, the application would use slabname##_at() to allocate a space to store data in (2), but there is no API other than slabname##_at() to use in step (3). This allocates and wastes new space for these commits the caller is only interested in checking if they have data stored in step (2). Introduce slabname##_peek(), which is similar to slabname##_at() but returns NULL when there is no data already associated to it in such a use case. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>	10 years ago
René Scharfe	2756ca4347	use REALLOC_ARRAY for changing the allocation size of arrays Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>	11 years ago
Jeff King	80cdaba569	commit-slab: provide a static initializer Callers currently must use init_foo_slab() at runtime before accessing a slab. For global slabs, it's much nicer if we can initialize them in BSS, so that each user does not have to add code to check-and-initialize. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>	11 years ago
Thomas Rast	cde0a0576c	commit-slab: sizeof() the right type in xrealloc When allocating the slab, the code accidentally computed the array size from s->slab (an elemtype*). The slab is an array of elemtype, however, so we should take the size of *s->slab. Noticed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Thomas Rast <tr@thomasrast.ch> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>	11 years ago
Thomas Rast	e9e03a7799	commit-slab: declare functions "static inline" This shuts up compiler warnings about unused functions. No such warnings are currently triggered, but if someone were to actually use init_NAME_with_stride() as documented, they would get a warning about init_NAME() being unused. While there, write a comment about why the last real declaration of the variable is without a terminating semicolon, while another forward declarations have one. Signed-off-by: Thomas Rast <tr@thomasrast.ch> Helped-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	11 years ago
Thomas Rast	dcbbc8fa2e	commit-slab: document clear_$slabname() The clear_$slabname() function was only documented by source code so far. Write something about it. Signed-off-by: Thomas Rast <tr@thomasrast.ch> Helped-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	11 years ago
Ramsay Jones	d7a1d629c3	commit-slab.h: Fix memory allocation and addressing The slab initialization code includes the calculation of the slab 'elem_size', which is in turn used to determine the size (capacity) of the slab. Each element of the slab represents an array, of length 'stride', of 'elemtype'. (Note that it may be clearer if the define_commit_slab macro parameter was called 'basetype' rather than 'elemtype'). However, the 'elem_size' calculation incorrectly uses 'sizeof(struct slabname)' in the expression, rather than 'sizeof(elemtype)'. Within the slab access routine, <slabname>_at(), the given commit 'index' is transformed into an (slab#, slot#) pair used to address the required element (a pointer to the first element of the array of 'elemtype' associated with that commit). The current code to calculate these address coordinates multiplies the commit index by the 'stride' which, at least for the slab#, produces the wrong result. Using the commit index directly, without scaling by the 'stride', produces the correct 'logical' address. Also, when allocating a new slab, the size of the allocation only allows for a slab containing elements of single element arrays of 'elemtype'. This should allow for elements of an array of length 'stride' of 'elemtype'. In order to fix this, we need to change the element size parameter to xcalloc() by multiplying the current element size (sizeof(**s->slab)) by the s->stride. Having changed the calculation of the slot#, we now need to convert the logical 'nth_slot', by scaling with s->stride, into the correct physical address. Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>	12 years ago
Junio C Hamano	a84b794ad0	commit-slab: introduce a macro to define a slab for new type Introduce a header file to define a macro that can define the struct type, initializer, accessor and cleanup functions to manage a commit slab. Update the "indegree" topological sort facility using it. To associate 32 flag bits with each commit, you can write: define_commit_slab(flag32, uint32); to declare "struct flag32" type, define an instance of it with struct flag32 flags; and initialize it by calling init_flag32(&flags); After that, a call to flag32_at() function uint32 fp = flag32_at(&flags, commit); will return a pointer pointing at a uint32 for that commit. Once you are done with these flags, clean them up with clear_flag32(&flags); Callers that cannot hard-code how wide the data to be associated with the commit be at compile time can use the "_with_stride" variant to initialize the slab. Suppose you want to give one bit per existing ref, and paint commits down to find which refs are descendants of each commit. Saying typedef uint32 bits320[5]; define_commit_slab(flagbits, bits320); at compile time will still limit your code with hard-coded limit, because you may find that you have more than 320 refs at runtime. The code can declare a commit slab "struct flagbits" like this instead: define_commit_slab(flagbits, unsigned char); struct flagbits flags; and initialize it by: nrefs = ... count number of refs ... init_flagbits_with_stride(&flags, (nrefs + 7) / 8); so that unsigned char fp = flagbits_at(&flags, commit); will return a pointer pointing at an array of 40 "unsigned char"s associated with the commit, once you figure out nrefs is 320 at runtime. Signed-off-by: Junio C Hamano <gitster@pobox.com>	12 years ago