6c648dd642
This is actually a fully functional build except: * All internal shared libraries are static linked to make sure there is no interference with ports (and to reduce build time). * It does not have the python/perl/etc plugin or API support. * By default, it installs as "svnlite" rather than "svn". * If WITH_SVN added in make.conf, you get "svn". * If WITHOUT_SVNLITE is in make.conf, this is completely disabled. To be absolutely clear, this is not intended for any use other than checking out freebsd source and committing, like we once did with cvs. It should be usable for small scale local repositories that don't need the python/perl plugin architecture.
514 lines
19 KiB
C
514 lines
19 KiB
C
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* This code draws heavily from the 4.4BSD <sys/queue.h> macros
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* and Dean Gaudet's "splim/ring.h".
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* <http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/sys/queue.h>
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* <http://www.arctic.org/~dean/splim/>
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*
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* We'd use Dean's code directly if we could guarantee the
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* availability of inline functions.
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*/
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#ifndef APR_RING_H
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#define APR_RING_H
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/**
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* @file apr_ring.h
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* @brief APR Rings
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*/
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/*
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* for offsetof()
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*/
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#include "apr_general.h"
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/**
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* @defgroup apr_ring Ring Macro Implementations
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* @ingroup APR
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* A ring is a kind of doubly-linked list that can be manipulated
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* without knowing where its head is.
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* @{
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*/
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/**
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* The Ring Element
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*
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* A ring element struct is linked to the other elements in the ring
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* through its ring entry field, e.g.
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* <pre>
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* struct my_element_t {
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* APR_RING_ENTRY(my_element_t) link;
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* int foo;
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* char *bar;
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* };
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* </pre>
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*
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* An element struct may be put on more than one ring if it has more
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* than one APR_RING_ENTRY field. Each APR_RING_ENTRY has a corresponding
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* APR_RING_HEAD declaration.
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*
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* @warning For strict C standards compliance you should put the APR_RING_ENTRY
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* first in the element struct unless the head is always part of a larger
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* object with enough earlier fields to accommodate the offsetof() used
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* to compute the ring sentinel below. You can usually ignore this caveat.
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*/
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#define APR_RING_ENTRY(elem) \
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struct { \
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struct elem * volatile next; \
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struct elem * volatile prev; \
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}
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/**
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* The Ring Head
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*
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* Each ring is managed via its head, which is a struct declared like this:
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* <pre>
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* APR_RING_HEAD(my_ring_t, my_element_t);
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* struct my_ring_t ring, *ringp;
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* </pre>
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*
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* This struct looks just like the element link struct so that we can
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* be sure that the typecasting games will work as expected.
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*
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* The first element in the ring is next after the head, and the last
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* element is just before the head.
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*/
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#define APR_RING_HEAD(head, elem) \
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struct head { \
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struct elem * volatile next; \
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struct elem * volatile prev; \
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}
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/**
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* The Ring Sentinel
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*
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* This is the magic pointer value that occurs before the first and
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* after the last elements in the ring, computed from the address of
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* the ring's head. The head itself isn't an element, but in order to
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* get rid of all the special cases when dealing with the ends of the
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* ring, we play typecasting games to make it look like one.
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*
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* Here is a diagram to illustrate the arrangements of the next and
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* prev pointers of each element in a single ring. Note that they point
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* to the start of each element, not to the APR_RING_ENTRY structure.
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*
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* <pre>
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* +->+------+<-+ +->+------+<-+ +->+------+<-+
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* | |struct| | | |struct| | | |struct| |
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* / | elem | \/ | elem | \/ | elem | \
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* ... | | /\ | | /\ | | ...
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* +------+ | | +------+ | | +------+
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* ...--|prev | | +--|ring | | +--|prev |
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* | next|--+ | entry|--+ | next|--...
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* +------+ +------+ +------+
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* | etc. | | etc. | | etc. |
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* : : : : : :
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* </pre>
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*
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* The APR_RING_HEAD is nothing but a bare APR_RING_ENTRY. The prev
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* and next pointers in the first and last elements don't actually
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* point to the head, they point to a phantom place called the
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* sentinel. Its value is such that last->next->next == first because
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* the offset from the sentinel to the head's next pointer is the same
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* as the offset from the start of an element to its next pointer.
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* This also works in the opposite direction.
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*
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* <pre>
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* last first
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* +->+------+<-+ +->sentinel<-+ +->+------+<-+
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* | |struct| | | | | |struct| |
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* / | elem | \/ \/ | elem | \
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* ... | | /\ /\ | | ...
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* +------+ | | +------+ | | +------+
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* ...--|prev | | +--|ring | | +--|prev |
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* | next|--+ | head|--+ | next|--...
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* +------+ +------+ +------+
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* | etc. | | etc. |
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* : : : :
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* </pre>
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*
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* Note that the offset mentioned above is different for each kind of
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* ring that the element may be on, and each kind of ring has a unique
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* name for its APR_RING_ENTRY in each element, and has its own type
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* for its APR_RING_HEAD.
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*
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* Note also that if the offset is non-zero (which is required if an
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* element has more than one APR_RING_ENTRY), the unreality of the
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* sentinel may have bad implications on very perverse implementations
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* of C -- see the warning in APR_RING_ENTRY.
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*
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* @param hp The head of the ring
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_SENTINEL(hp, elem, link) \
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(struct elem *)((char *)(&(hp)->next) - APR_OFFSETOF(struct elem, link))
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/**
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* The first element of the ring
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* @param hp The head of the ring
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*/
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#define APR_RING_FIRST(hp) (hp)->next
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/**
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* The last element of the ring
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* @param hp The head of the ring
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*/
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#define APR_RING_LAST(hp) (hp)->prev
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/**
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* The next element in the ring
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* @param ep The current element
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_NEXT(ep, link) (ep)->link.next
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/**
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* The previous element in the ring
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* @param ep The current element
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_PREV(ep, link) (ep)->link.prev
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/**
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* Initialize a ring
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* @param hp The head of the ring
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_INIT(hp, elem, link) do { \
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APR_RING_FIRST((hp)) = APR_RING_SENTINEL((hp), elem, link); \
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APR_RING_LAST((hp)) = APR_RING_SENTINEL((hp), elem, link); \
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} while (0)
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/**
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* Determine if a ring is empty
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* @param hp The head of the ring
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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* @return true or false
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*/
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#define APR_RING_EMPTY(hp, elem, link) \
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(APR_RING_FIRST((hp)) == APR_RING_SENTINEL((hp), elem, link))
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/**
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* Initialize a singleton element
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* @param ep The element
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_ELEM_INIT(ep, link) do { \
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APR_RING_NEXT((ep), link) = (ep); \
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APR_RING_PREV((ep), link) = (ep); \
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} while (0)
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/**
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* Splice the sequence ep1..epN into the ring before element lep
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* (..lep.. becomes ..ep1..epN..lep..)
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* @warning This doesn't work for splicing before the first element or on
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* empty rings... see APR_RING_SPLICE_HEAD for one that does
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* @param lep Element in the ring to splice before
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* @param ep1 First element in the sequence to splice in
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* @param epN Last element in the sequence to splice in
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_SPLICE_BEFORE(lep, ep1, epN, link) do { \
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APR_RING_NEXT((epN), link) = (lep); \
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APR_RING_PREV((ep1), link) = APR_RING_PREV((lep), link); \
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APR_RING_NEXT(APR_RING_PREV((lep), link), link) = (ep1); \
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APR_RING_PREV((lep), link) = (epN); \
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} while (0)
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/**
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* Splice the sequence ep1..epN into the ring after element lep
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* (..lep.. becomes ..lep..ep1..epN..)
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* @warning This doesn't work for splicing after the last element or on
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* empty rings... see APR_RING_SPLICE_TAIL for one that does
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* @param lep Element in the ring to splice after
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* @param ep1 First element in the sequence to splice in
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* @param epN Last element in the sequence to splice in
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_SPLICE_AFTER(lep, ep1, epN, link) do { \
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APR_RING_PREV((ep1), link) = (lep); \
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APR_RING_NEXT((epN), link) = APR_RING_NEXT((lep), link); \
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APR_RING_PREV(APR_RING_NEXT((lep), link), link) = (epN); \
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APR_RING_NEXT((lep), link) = (ep1); \
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} while (0)
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/**
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* Insert the element nep into the ring before element lep
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* (..lep.. becomes ..nep..lep..)
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* @warning This doesn't work for inserting before the first element or on
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* empty rings... see APR_RING_INSERT_HEAD for one that does
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* @param lep Element in the ring to insert before
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* @param nep Element to insert
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_INSERT_BEFORE(lep, nep, link) \
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APR_RING_SPLICE_BEFORE((lep), (nep), (nep), link)
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/**
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* Insert the element nep into the ring after element lep
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* (..lep.. becomes ..lep..nep..)
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* @warning This doesn't work for inserting after the last element or on
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* empty rings... see APR_RING_INSERT_TAIL for one that does
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* @param lep Element in the ring to insert after
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* @param nep Element to insert
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_INSERT_AFTER(lep, nep, link) \
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APR_RING_SPLICE_AFTER((lep), (nep), (nep), link)
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/**
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* Splice the sequence ep1..epN into the ring before the first element
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* (..hp.. becomes ..hp..ep1..epN..)
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* @param hp Head of the ring
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* @param ep1 First element in the sequence to splice in
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* @param epN Last element in the sequence to splice in
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_SPLICE_HEAD(hp, ep1, epN, elem, link) \
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APR_RING_SPLICE_AFTER(APR_RING_SENTINEL((hp), elem, link), \
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(ep1), (epN), link)
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/**
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* Splice the sequence ep1..epN into the ring after the last element
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* (..hp.. becomes ..ep1..epN..hp..)
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* @param hp Head of the ring
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* @param ep1 First element in the sequence to splice in
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* @param epN Last element in the sequence to splice in
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_SPLICE_TAIL(hp, ep1, epN, elem, link) \
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APR_RING_SPLICE_BEFORE(APR_RING_SENTINEL((hp), elem, link), \
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(ep1), (epN), link)
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/**
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* Insert the element nep into the ring before the first element
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* (..hp.. becomes ..hp..nep..)
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* @param hp Head of the ring
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* @param nep Element to insert
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_INSERT_HEAD(hp, nep, elem, link) \
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APR_RING_SPLICE_HEAD((hp), (nep), (nep), elem, link)
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/**
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* Insert the element nep into the ring after the last element
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* (..hp.. becomes ..nep..hp..)
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* @param hp Head of the ring
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* @param nep Element to insert
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_INSERT_TAIL(hp, nep, elem, link) \
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APR_RING_SPLICE_TAIL((hp), (nep), (nep), elem, link)
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/**
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* Concatenate ring h2 onto the end of ring h1, leaving h2 empty.
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* @param h1 Head of the ring to concatenate onto
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* @param h2 Head of the ring to concatenate
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_CONCAT(h1, h2, elem, link) do { \
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if (!APR_RING_EMPTY((h2), elem, link)) { \
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APR_RING_SPLICE_BEFORE(APR_RING_SENTINEL((h1), elem, link), \
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APR_RING_FIRST((h2)), \
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APR_RING_LAST((h2)), link); \
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APR_RING_INIT((h2), elem, link); \
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} \
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} while (0)
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/**
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* Prepend ring h2 onto the beginning of ring h1, leaving h2 empty.
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* @param h1 Head of the ring to prepend onto
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* @param h2 Head of the ring to prepend
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_PREPEND(h1, h2, elem, link) do { \
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if (!APR_RING_EMPTY((h2), elem, link)) { \
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APR_RING_SPLICE_AFTER(APR_RING_SENTINEL((h1), elem, link), \
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APR_RING_FIRST((h2)), \
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APR_RING_LAST((h2)), link); \
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APR_RING_INIT((h2), elem, link); \
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} \
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} while (0)
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/**
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* Unsplice a sequence of elements from a ring
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* @warning The unspliced sequence is left with dangling pointers at either end
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* @param ep1 First element in the sequence to unsplice
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* @param epN Last element in the sequence to unsplice
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_UNSPLICE(ep1, epN, link) do { \
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APR_RING_NEXT(APR_RING_PREV((ep1), link), link) = \
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APR_RING_NEXT((epN), link); \
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APR_RING_PREV(APR_RING_NEXT((epN), link), link) = \
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APR_RING_PREV((ep1), link); \
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} while (0)
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/**
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* Remove a single element from a ring
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* @warning The unspliced element is left with dangling pointers at either end
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* @param ep Element to remove
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_REMOVE(ep, link) \
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APR_RING_UNSPLICE((ep), (ep), link)
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/**
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* Iterate over a ring
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* @param ep The current element
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* @param head The head of the ring
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_FOREACH(ep, head, elem, link) \
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for (ep = APR_RING_FIRST(head); \
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ep != APR_RING_SENTINEL(head, elem, link); \
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ep = APR_RING_NEXT(ep, link))
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/**
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* Iterate over a ring safe against removal of the current element
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* @param ep1 The current element
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* @param ep2 Iteration cursor
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* @param head The head of the ring
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* @param elem The name of the element struct
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* @param link The name of the APR_RING_ENTRY in the element struct
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*/
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#define APR_RING_FOREACH_SAFE(ep1, ep2, head, elem, link) \
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for (ep1 = APR_RING_FIRST(head), ep2 = APR_RING_NEXT(ep1, link); \
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ep1 != APR_RING_SENTINEL(head, elem, link); \
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ep1 = ep2, ep2 = APR_RING_NEXT(ep1, link))
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/* Debugging tools: */
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#ifdef APR_RING_DEBUG
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#include <stdio.h>
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#include <assert.h>
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#define APR_RING_CHECK_ONE(msg, ptr) \
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fprintf(stderr, "*** %s %p\n", msg, ptr)
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#define APR_RING_CHECK(hp, elem, link, msg) \
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APR_RING_CHECK_ELEM(APR_RING_SENTINEL(hp, elem, link), elem, link, msg)
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#define APR_RING_CHECK_ELEM(ep, elem, link, msg) do { \
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struct elem *start = (ep); \
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struct elem *here = start; \
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fprintf(stderr, "*** ring check start -- %s\n", msg); \
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do { \
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fprintf(stderr, "\telem %p\n", here); \
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fprintf(stderr, "\telem->next %p\n", \
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APR_RING_NEXT(here, link)); \
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fprintf(stderr, "\telem->prev %p\n", \
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APR_RING_PREV(here, link)); \
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fprintf(stderr, "\telem->next->prev %p\n", \
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APR_RING_PREV(APR_RING_NEXT(here, link), link)); \
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fprintf(stderr, "\telem->prev->next %p\n", \
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APR_RING_NEXT(APR_RING_PREV(here, link), link)); \
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if (APR_RING_PREV(APR_RING_NEXT(here, link), link) != here) { \
|
|
fprintf(stderr, "\t*** elem->next->prev != elem\n"); \
|
|
break; \
|
|
} \
|
|
if (APR_RING_NEXT(APR_RING_PREV(here, link), link) != here) { \
|
|
fprintf(stderr, "\t*** elem->prev->next != elem\n"); \
|
|
break; \
|
|
} \
|
|
here = APR_RING_NEXT(here, link); \
|
|
} while (here != start); \
|
|
fprintf(stderr, "*** ring check end\n"); \
|
|
} while (0)
|
|
|
|
#define APR_RING_CHECK_CONSISTENCY(hp, elem, link) \
|
|
APR_RING_CHECK_ELEM_CONSISTENCY(APR_RING_SENTINEL(hp, elem, link),\
|
|
elem, link)
|
|
|
|
#define APR_RING_CHECK_ELEM_CONSISTENCY(ep, elem, link) do { \
|
|
struct elem *start = (ep); \
|
|
struct elem *here = start; \
|
|
do { \
|
|
assert(APR_RING_PREV(APR_RING_NEXT(here, link), link) == here); \
|
|
assert(APR_RING_NEXT(APR_RING_PREV(here, link), link) == here); \
|
|
here = APR_RING_NEXT(here, link); \
|
|
} while (here != start); \
|
|
} while (0)
|
|
|
|
#else
|
|
/**
|
|
* Print a single pointer value to STDERR
|
|
* (This is a no-op unless APR_RING_DEBUG is defined.)
|
|
* @param msg Descriptive message
|
|
* @param ptr Pointer value to print
|
|
*/
|
|
#define APR_RING_CHECK_ONE(msg, ptr)
|
|
/**
|
|
* Dump all ring pointers to STDERR, starting with the head and looping all
|
|
* the way around the ring back to the head. Aborts if an inconsistency
|
|
* is found.
|
|
* (This is a no-op unless APR_RING_DEBUG is defined.)
|
|
* @param hp Head of the ring
|
|
* @param elem The name of the element struct
|
|
* @param link The name of the APR_RING_ENTRY in the element struct
|
|
* @param msg Descriptive message
|
|
*/
|
|
#define APR_RING_CHECK(hp, elem, link, msg)
|
|
/**
|
|
* Loops around a ring and checks all the pointers for consistency. Pops
|
|
* an assertion if any inconsistency is found. Same idea as APR_RING_CHECK()
|
|
* except that it's silent if all is well.
|
|
* (This is a no-op unless APR_RING_DEBUG is defined.)
|
|
* @param hp Head of the ring
|
|
* @param elem The name of the element struct
|
|
* @param link The name of the APR_RING_ENTRY in the element struct
|
|
*/
|
|
#define APR_RING_CHECK_CONSISTENCY(hp, elem, link)
|
|
/**
|
|
* Dump all ring pointers to STDERR, starting with the given element and
|
|
* looping all the way around the ring back to that element. Aborts if
|
|
* an inconsistency is found.
|
|
* (This is a no-op unless APR_RING_DEBUG is defined.)
|
|
* @param ep The element
|
|
* @param elem The name of the element struct
|
|
* @param link The name of the APR_RING_ENTRY in the element struct
|
|
* @param msg Descriptive message
|
|
*/
|
|
#define APR_RING_CHECK_ELEM(ep, elem, link, msg)
|
|
/**
|
|
* Loops around a ring, starting with the given element, and checks all
|
|
* the pointers for consistency. Pops an assertion if any inconsistency
|
|
* is found. Same idea as APR_RING_CHECK_ELEM() except that it's silent
|
|
* if all is well.
|
|
* (This is a no-op unless APR_RING_DEBUG is defined.)
|
|
* @param ep The element
|
|
* @param elem The name of the element struct
|
|
* @param link The name of the APR_RING_ENTRY in the element struct
|
|
*/
|
|
#define APR_RING_CHECK_ELEM_CONSISTENCY(ep, elem, link)
|
|
#endif
|
|
|
|
/** @} */
|
|
|
|
#endif /* !APR_RING_H */
|