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cb69b4c7 | 1 | /* |
bbc27441 | 2 | * Copyright (C) 1996-2014 The Squid Software Foundation and contributors |
e25c139f | 3 | * |
bbc27441 AJ |
4 | * Squid software is distributed under GPLv2+ license and includes |
5 | * contributions from numerous individuals and organizations. | |
6 | * Please see the COPYING and CONTRIBUTORS files for details. | |
cb69b4c7 | 7 | */ |
8 | ||
bbc27441 AJ |
9 | /* DEBUG: section 60 Packer: A uniform interface to store-like modules */ |
10 | ||
adba4a64 | 11 | /* |
2ac76861 | 12 | * Rationale: |
13 | * ---------- | |
26ac0430 | 14 | * |
bbc27441 | 15 | * OK, we have two major interfaces comm.c and store.c. |
26ac0430 | 16 | * |
2ac76861 | 17 | * Store.c has a nice storeAppend[Printf] capability which makes "storing" |
26ac0430 AJ |
18 | * things easy and painless. |
19 | * | |
2ac76861 | 20 | * Comm.c lacks commAppend[Printf] because comm does not handle its own |
21 | * buffers (no mem_obj equivalent for comm.c). | |
26ac0430 | 22 | * |
ec41b64c | 23 | * Thus, if one wants to be able to store _and_ Comm::Write an object, s/he |
2ac76861 | 24 | * has to implement two almost identical functions. |
26ac0430 | 25 | * |
2ac76861 | 26 | * Packer |
27 | * ------ | |
26ac0430 | 28 | * |
2ac76861 | 29 | * Packer provides for a more uniform interface to store and comm modules. |
30 | * Packer has its own append and printf routines that "know" where to send | |
31 | * incoming data. In case of store interface, Packer sends data to | |
32 | * storeAppend. Otherwise, Packer uses a MemBuf that can be flushed later to | |
ec41b64c | 33 | * Comm::Write. |
26ac0430 | 34 | * |
2ac76861 | 35 | * Thus, one can write just one function that will either "pack" things for |
ec41b64c | 36 | * Comm::Write or "append" things to store, depending on actual packer |
2ac76861 | 37 | * supplied. |
26ac0430 | 38 | * |
eb139d08 | 39 | * It is amazing how much work a tiny object can save. :) |
cb69b4c7 | 40 | */ |
41 | ||
582c2af2 | 42 | #include "squid.h" |
0eb49b6d | 43 | #include "MemBuf.h" |
602d9612 | 44 | #include "Store.h" |
cb69b4c7 | 45 | |
cb69b4c7 | 46 | /* |
47 | * We do have one potential problem here. Both append_f and vprintf_f types | |
48 | * cannot match real functions precisely (at least because of the difference in | |
49 | * the type of the first parameter). Thus, we have to use type cast. If somebody | |
50 | * changes the prototypes of real functions, Packer will not notice that because | |
51 | * of the type cast. | |
52 | * | |
53 | * Solution: we use the constants below to *hard code* current prototypes of | |
54 | * real functions. If real prototypes change, these constants will produce a | |
55 | * warning (e.g., "warning: assignment from incompatible pointer type"). | |
56 | */ | |
57 | ||
2fe7eff9 | 58 | static void |
59 | memBufAppend(MemBuf *mb, const char *buf, mb_size_t len) | |
60 | { | |
61 | mb->append(buf, len); | |
62 | } | |
63 | ||
64 | static void | |
65 | memBufVPrintf(MemBuf * mb, const char *fmt, va_list vargs) | |
66 | { | |
67 | mb->vPrintf(fmt, vargs); | |
68 | } | |
69 | ||
3900307b | 70 | static void |
71 | storeEntryAppend(StoreEntry *e, const char *buf, int len) | |
72 | { | |
73 | e->append(buf, len); | |
74 | } | |
75 | ||
cb69b4c7 | 76 | /* append()'s */ |
3900307b | 77 | static void (*const store_append) (StoreEntry *, const char *, int) = &storeEntryAppend; |
2ac76861 | 78 | static void (*const memBuf_append) (MemBuf *, const char *, mb_size_t) = &memBufAppend; |
cb69b4c7 | 79 | |
80 | /* vprintf()'s */ | |
2ac76861 | 81 | static void (*const store_vprintf) (StoreEntry *, const char *, va_list ap) = &storeAppendVPrintf; |
82 | static void (*const memBuf_vprintf) (MemBuf *, const char *, va_list ap) = &memBufVPrintf; | |
cb69b4c7 | 83 | |
adba4a64 | 84 | /* init/clean */ |
85 | ||
86 | /* init with this to forward data to StoreEntry */ | |
cb69b4c7 | 87 | void |
2ac76861 | 88 | packerToStoreInit(Packer * p, StoreEntry * e) |
cb69b4c7 | 89 | { |
90 | assert(p && e); | |
2ac76861 | 91 | p->append = (append_f) store_append; |
866be921 | 92 | p->packer_vprintf = (vprintf_f) store_vprintf; |
cb69b4c7 | 93 | p->real_handler = e; |
3900307b | 94 | e->buffer(); |
cb69b4c7 | 95 | } |
96 | ||
adba4a64 | 97 | /* init with this to accumulate data in MemBuf */ |
cb69b4c7 | 98 | void |
2ac76861 | 99 | packerToMemInit(Packer * p, MemBuf * mb) |
cb69b4c7 | 100 | { |
101 | assert(p && mb); | |
2ac76861 | 102 | p->append = (append_f) memBuf_append; |
866be921 | 103 | p->packer_vprintf = (vprintf_f) memBuf_vprintf; |
cb69b4c7 | 104 | p->real_handler = mb; |
105 | } | |
106 | ||
adba4a64 | 107 | /* call this when you are done */ |
cb69b4c7 | 108 | void |
2ac76861 | 109 | packerClean(Packer * p) |
cb69b4c7 | 110 | { |
2ac76861 | 111 | assert(p); |
b89401f3 | 112 | |
113 | if (p->append == (append_f) store_append && p->real_handler) | |
3900307b | 114 | static_cast<StoreEntry*>(p->real_handler)->flush(); |
b89401f3 | 115 | |
2ac76861 | 116 | /* it is not really necessary to do this, but, just in case... */ |
117 | p->append = NULL; | |
866be921 | 118 | p->packer_vprintf = NULL; |
2ac76861 | 119 | p->real_handler = NULL; |
cb69b4c7 | 120 | } |
121 | ||
122 | void | |
2ac76861 | 123 | packerAppend(Packer * p, const char *buf, int sz) |
cb69b4c7 | 124 | { |
125 | assert(p); | |
126 | assert(p->real_handler && p->append); | |
127 | p->append(p->real_handler, buf, sz); | |
128 | } | |
129 | ||
cb69b4c7 | 130 | void |
2ac76861 | 131 | packerPrintf(Packer * p, const char *fmt,...) |
cb69b4c7 | 132 | { |
133 | va_list args; | |
134 | va_start(args, fmt); | |
62e76326 | 135 | |
cb69b4c7 | 136 | assert(p); |
866be921 | 137 | assert(p->real_handler && p->packer_vprintf); |
138 | p->packer_vprintf(p->real_handler, fmt, args); | |
cb69b4c7 | 139 | va_end(args); |
140 | } |