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e1111cef23
In a repository without object replacement, lookup_replace_object() should be a no-op. Check the flag "read_replace_refs" on the side of the caller, and bypess a function call when we know we are not dealing with replacement. Also, even when we are set up to replace objects, if we do not find any replacement defined, flip that flag off to avoid function call overhead for all the later object accesses. As this change the semantics of the flag from "do we need read the replacement definition?" to "do we need to check with the lookup table?" the flag needs to be renamed later to something saner, e.g. "use_replace", when the codebase is calmer, but not now. Signed-off-by: Junio C Hamano <gitster@pobox.com>
117 lines
2.7 KiB
C
117 lines
2.7 KiB
C
#include "cache.h"
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#include "sha1-lookup.h"
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#include "refs.h"
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#include "commit.h"
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static struct replace_object {
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unsigned char sha1[2][20];
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} **replace_object;
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static int replace_object_alloc, replace_object_nr;
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static const unsigned char *replace_sha1_access(size_t index, void *table)
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{
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struct replace_object **replace = table;
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return replace[index]->sha1[0];
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}
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static int replace_object_pos(const unsigned char *sha1)
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{
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return sha1_pos(sha1, replace_object, replace_object_nr,
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replace_sha1_access);
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}
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static int register_replace_object(struct replace_object *replace,
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int ignore_dups)
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{
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int pos = replace_object_pos(replace->sha1[0]);
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if (0 <= pos) {
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if (ignore_dups)
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free(replace);
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else {
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free(replace_object[pos]);
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replace_object[pos] = replace;
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}
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return 1;
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}
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pos = -pos - 1;
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if (replace_object_alloc <= ++replace_object_nr) {
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replace_object_alloc = alloc_nr(replace_object_alloc);
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replace_object = xrealloc(replace_object,
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sizeof(*replace_object) *
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replace_object_alloc);
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}
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if (pos < replace_object_nr)
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memmove(replace_object + pos + 1,
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replace_object + pos,
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(replace_object_nr - pos - 1) *
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sizeof(*replace_object));
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replace_object[pos] = replace;
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return 0;
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}
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static int register_replace_ref(const char *refname,
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const unsigned char *sha1,
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int flag, void *cb_data)
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{
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/* Get sha1 from refname */
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const char *slash = strrchr(refname, '/');
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const char *hash = slash ? slash + 1 : refname;
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struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
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if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->sha1[0])) {
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free(repl_obj);
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warning("bad replace ref name: %s", refname);
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return 0;
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}
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/* Copy sha1 from the read ref */
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hashcpy(repl_obj->sha1[1], sha1);
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/* Register new object */
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if (register_replace_object(repl_obj, 1))
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die("duplicate replace ref: %s", refname);
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return 0;
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}
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static void prepare_replace_object(void)
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{
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static int replace_object_prepared;
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if (replace_object_prepared)
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return;
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for_each_replace_ref(register_replace_ref, NULL);
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replace_object_prepared = 1;
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if (!replace_object_nr)
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read_replace_refs = 0;
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}
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/* We allow "recursive" replacement. Only within reason, though */
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#define MAXREPLACEDEPTH 5
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const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
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{
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int pos, depth = MAXREPLACEDEPTH;
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const unsigned char *cur = sha1;
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if (!read_replace_refs)
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return sha1;
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prepare_replace_object();
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/* Try to recursively replace the object */
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do {
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if (--depth < 0)
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die("replace depth too high for object %s",
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sha1_to_hex(sha1));
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pos = replace_object_pos(cur);
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if (0 <= pos)
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cur = replace_object[pos]->sha1[1];
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} while (0 <= pos);
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return cur;
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}
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