123 lines
3.0 KiB
C
123 lines
3.0 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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/*
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* An array of replacements. The array is kept sorted by the original
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* sha1.
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*/
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static struct replace_object {
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unsigned char original[20];
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unsigned char replacement[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]->original;
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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->original);
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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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ALLOC_GROW(replace_object, replace_object_nr + 1, replace_object_alloc);
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replace_object_nr++;
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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 struct object_id *oid,
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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->original)) {
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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->replacement, oid->hash);
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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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check_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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/*
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* If a replacement for object sha1 has been set up, return the
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* replacement object's name (replaced recursively, if necessary).
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* The return value is either sha1 or a pointer to a
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* permanently-allocated value. This function always respects replace
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* references, regardless of the value of check_replace_refs.
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*/
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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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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]->replacement;
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} while (0 <= pos);
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return cur;
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}
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