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git/commit-slab.h

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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>
10 years ago
#ifndef COMMIT_SLAB_H
#define COMMIT_SLAB_H
#include "commit-slab-decl.h"
#include "commit-slab-impl.h"
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>
10 years ago
/*
* define_commit_slab(slabname, elemtype) creates boilerplate code to define
* a new struct (struct slabname) that is used to associate a piece of data
* of elemtype to commits, and a few functions to use that struct.
*
* After including this header file, using:
*
* define_commit_slab(indegree, int);
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>
10 years ago
*
* will let you call the following functions:
*
* - int *indegree_at(struct indegree *, struct commit *);
*
* This function locates the data associated with the given commit in
* the indegree slab, and returns the pointer to it. The location to
* store the data is allocated as necessary.
*
* - int *indegree_peek(struct indegree *, struct commit *);
*
* This function is similar to indegree_at(), but it will return NULL
* if the location to store the data associated with the given commit
* has not been allocated yet.
* Note that the location to store the data might have already been
* allocated even if no indegree_at() call has been made for that commit
* yet; in this case this function returns a pointer to a
* zero-initialized location.
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>
10 years ago
*
* - void init_indegree(struct indegree *);
* void init_indegree_with_stride(struct indegree *, int);
*
* Initializes the indegree slab that associates an array of integers
* to each commit. 'stride' specifies how big each array is. The slab
* that is initialized by the variant without "_with_stride" associates
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>
10 years ago
* each commit with an array of one integer.
*
* - void clear_indegree(struct indegree *);
*
* Empties the slab. The slab can be reused with the same stride
* without calling init_indegree() again or can be reconfigured to a
* different stride by calling init_indegree_with_stride().
*
* Call this function before the slab falls out of scope to avoid
* leaking memory.
*
* - void deep_clear_indegree(struct indegree *, void (*free_fn)(int*))
*
* Empties the slab, similar to clear_indegree(), but in addition it
* calls the given 'free_fn' for each slab entry to release any
* additional memory that might be owned by the entry (but not the
* entry itself!).
* Note that 'free_fn' might be called even for entries for which no
* indegree_at() call has been made; in this case 'free_fn' is invoked
* with a pointer to a zero-initialized location.
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>
10 years ago
*/
#define define_commit_slab(slabname, elemtype) \
declare_commit_slab(slabname, elemtype); \
implement_static_commit_slab(slabname, elemtype)
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>
10 years ago
#endif /* COMMIT_SLAB_H */