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9e20442298
Finish the change started in the preceding commit and allow an early return from "xdiff_emit_line_fn" callbacks, this will allows diffcore-pickaxe.c to save itself redundant work. Our xdiff interface also had the limitation of not being able to abort early since the beginning, seed9ea73e056
(combine-diff: refactor built-in xdiff interface., 2006-04-05). Although at that time "xdiff_emit_line_fn" was called "xdiff_emit_consume_fn", and "xdiff_emit_hunk_fn" didn't exist yet. There was some work in this area of xdiff-interface.[ch] recently with3b40a090fd
(diff: avoid generating unused hunk header lines, 2018-11-02) and7c61e25fbf
(diff: use hunk callback for word-diff, 2018-11-02). In combination those two changes allow us to not do any work on the hunks and diff at all, but didn't change the status quo with regards to consumers that e.g. want the diff lines, but might want to abort early. Whereas now we can abort e.g. on the first "-line" of a 1000 line diff if that's all we needed. This interface is rather scary as noted in the comment to xdiff-interface.h being added here, as noted there a future change could add more exit codes, and hack xdl_emit_diff() and friends to ignore or skip things more selectively as a result. I did not see an inherent reason for why xdl_emit_{diffrec,record}() could not be changed to ferry the "xdiff_emit_line_fn" error code upwards instead of returning -1 on all "ret < 0". But doing so would require corresponding changes in xdl_emit_diff(), xdl_diff(). I didn't see any issue with narrowly doing that to accomplish what I needed here, but it would leave xdiff's own return values in an inconsistent state. Instead I've left it at returning a more conventional (for git's own codebase) 1 for an early return, and translating it (or rather, all non-zero) to -1 for xdiff's consumption. The reason for most of the "stop" complexity in xdiff_outf() is because we want to be able to abort early, but do so in a way that doesn't skip the appropriate strbuf_reset() invocations. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
335 lines
7.6 KiB
C
335 lines
7.6 KiB
C
#include "cache.h"
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#include "config.h"
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#include "object-store.h"
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#include "xdiff-interface.h"
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#include "xdiff/xtypes.h"
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#include "xdiff/xdiffi.h"
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#include "xdiff/xemit.h"
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#include "xdiff/xmacros.h"
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#include "xdiff/xutils.h"
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struct xdiff_emit_state {
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xdiff_emit_hunk_fn hunk_fn;
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xdiff_emit_line_fn line_fn;
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void *consume_callback_data;
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struct strbuf remainder;
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};
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static int xdiff_out_hunk(void *priv_,
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long old_begin, long old_nr,
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long new_begin, long new_nr,
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const char *func, long funclen)
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{
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struct xdiff_emit_state *priv = priv_;
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if (priv->remainder.len)
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BUG("xdiff emitted hunk in the middle of a line");
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priv->hunk_fn(priv->consume_callback_data,
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old_begin, old_nr, new_begin, new_nr,
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func, funclen);
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return 0;
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}
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static int consume_one(void *priv_, char *s, unsigned long size)
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{
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struct xdiff_emit_state *priv = priv_;
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char *ep;
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while (size) {
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unsigned long this_size;
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int ret;
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ep = memchr(s, '\n', size);
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this_size = (ep == NULL) ? size : (ep - s + 1);
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ret = priv->line_fn(priv->consume_callback_data, s, this_size);
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if (ret)
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return ret;
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size -= this_size;
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s += this_size;
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}
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return 0;
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}
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static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
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{
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struct xdiff_emit_state *priv = priv_;
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int i;
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int stop = 0;
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if (!priv->line_fn)
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return 0;
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for (i = 0; i < nbuf; i++) {
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if (stop)
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return 1;
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if (mb[i].ptr[mb[i].size-1] != '\n') {
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/* Incomplete line */
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strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
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continue;
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}
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/* we have a complete line */
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if (!priv->remainder.len) {
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stop = consume_one(priv, mb[i].ptr, mb[i].size);
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continue;
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}
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strbuf_add(&priv->remainder, mb[i].ptr, mb[i].size);
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stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
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strbuf_reset(&priv->remainder);
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}
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if (stop)
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return -1;
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if (priv->remainder.len) {
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stop = consume_one(priv, priv->remainder.buf, priv->remainder.len);
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strbuf_reset(&priv->remainder);
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}
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if (stop)
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return -1;
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return 0;
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}
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/*
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* Trim down common substring at the end of the buffers,
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* but end on a complete line.
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*/
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static void trim_common_tail(mmfile_t *a, mmfile_t *b)
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{
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const int blk = 1024;
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long trimmed = 0, recovered = 0;
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char *ap = a->size ? a->ptr + a->size : a->ptr;
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char *bp = b->size ? b->ptr + b->size : b->ptr;
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long smaller = (a->size < b->size) ? a->size : b->size;
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while (blk + trimmed <= smaller && !memcmp(ap - blk, bp - blk, blk)) {
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trimmed += blk;
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ap -= blk;
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bp -= blk;
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}
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while (recovered < trimmed)
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if (ap[recovered++] == '\n')
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break;
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a->size -= trimmed - recovered;
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b->size -= trimmed - recovered;
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}
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int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *xecb)
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{
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mmfile_t a = *mf1;
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mmfile_t b = *mf2;
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if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
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return -1;
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if (!xecfg->ctxlen && !(xecfg->flags & XDL_EMIT_FUNCCONTEXT))
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trim_common_tail(&a, &b);
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return xdl_diff(&a, &b, xpp, xecfg, xecb);
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}
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void discard_hunk_line(void *priv,
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long ob, long on, long nb, long nn,
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const char *func, long funclen)
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{
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}
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int xdi_diff_outf(mmfile_t *mf1, mmfile_t *mf2,
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xdiff_emit_hunk_fn hunk_fn,
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xdiff_emit_line_fn line_fn,
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void *consume_callback_data,
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xpparam_t const *xpp, xdemitconf_t const *xecfg)
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{
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int ret;
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struct xdiff_emit_state state;
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xdemitcb_t ecb;
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memset(&state, 0, sizeof(state));
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state.hunk_fn = hunk_fn;
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state.line_fn = line_fn;
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state.consume_callback_data = consume_callback_data;
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memset(&ecb, 0, sizeof(ecb));
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if (hunk_fn)
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ecb.out_hunk = xdiff_out_hunk;
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ecb.out_line = xdiff_outf;
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ecb.priv = &state;
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strbuf_init(&state.remainder, 0);
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ret = xdi_diff(mf1, mf2, xpp, xecfg, &ecb);
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strbuf_release(&state.remainder);
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return ret;
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}
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int read_mmfile(mmfile_t *ptr, const char *filename)
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{
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struct stat st;
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FILE *f;
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size_t sz;
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if (stat(filename, &st))
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return error_errno("Could not stat %s", filename);
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if ((f = fopen(filename, "rb")) == NULL)
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return error_errno("Could not open %s", filename);
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sz = xsize_t(st.st_size);
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ptr->ptr = xmalloc(sz ? sz : 1);
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if (sz && fread(ptr->ptr, sz, 1, f) != 1) {
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fclose(f);
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return error("Could not read %s", filename);
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}
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fclose(f);
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ptr->size = sz;
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return 0;
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}
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void read_mmblob(mmfile_t *ptr, const struct object_id *oid)
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{
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unsigned long size;
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enum object_type type;
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if (oideq(oid, &null_oid)) {
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ptr->ptr = xstrdup("");
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ptr->size = 0;
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return;
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}
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ptr->ptr = read_object_file(oid, &type, &size);
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if (!ptr->ptr || type != OBJ_BLOB)
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die("unable to read blob object %s", oid_to_hex(oid));
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ptr->size = size;
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}
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#define FIRST_FEW_BYTES 8000
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int buffer_is_binary(const char *ptr, unsigned long size)
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{
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if (FIRST_FEW_BYTES < size)
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size = FIRST_FEW_BYTES;
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return !!memchr(ptr, 0, size);
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}
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struct ff_regs {
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int nr;
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struct ff_reg {
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regex_t re;
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int negate;
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} *array;
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};
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static long ff_regexp(const char *line, long len,
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char *buffer, long buffer_size, void *priv)
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{
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struct ff_regs *regs = priv;
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regmatch_t pmatch[2];
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int i;
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int result;
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/* Exclude terminating newline (and cr) from matching */
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if (len > 0 && line[len-1] == '\n') {
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if (len > 1 && line[len-2] == '\r')
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len -= 2;
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else
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len--;
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}
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for (i = 0; i < regs->nr; i++) {
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struct ff_reg *reg = regs->array + i;
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if (!regexec_buf(®->re, line, len, 2, pmatch, 0)) {
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if (reg->negate)
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return -1;
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break;
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}
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}
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if (regs->nr <= i)
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return -1;
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i = pmatch[1].rm_so >= 0 ? 1 : 0;
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line += pmatch[i].rm_so;
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result = pmatch[i].rm_eo - pmatch[i].rm_so;
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if (result > buffer_size)
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result = buffer_size;
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while (result > 0 && (isspace(line[result - 1])))
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result--;
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memcpy(buffer, line, result);
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return result;
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}
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void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
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{
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int i;
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struct ff_regs *regs;
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xecfg->find_func = ff_regexp;
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regs = xecfg->find_func_priv = xmalloc(sizeof(struct ff_regs));
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for (i = 0, regs->nr = 1; value[i]; i++)
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if (value[i] == '\n')
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regs->nr++;
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ALLOC_ARRAY(regs->array, regs->nr);
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for (i = 0; i < regs->nr; i++) {
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struct ff_reg *reg = regs->array + i;
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const char *ep, *expression;
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char *buffer = NULL;
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if (!value)
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BUG("mismatch between line count and parsing");
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ep = strchr(value, '\n');
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reg->negate = (*value == '!');
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if (reg->negate && i == regs->nr - 1)
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die("Last expression must not be negated: %s", value);
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if (*value == '!')
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value++;
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if (ep)
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expression = buffer = xstrndup(value, ep - value);
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else
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expression = value;
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if (regcomp(®->re, expression, cflags))
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die("Invalid regexp to look for hunk header: %s", expression);
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free(buffer);
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value = ep ? ep + 1 : NULL;
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}
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}
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void xdiff_clear_find_func(xdemitconf_t *xecfg)
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{
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if (xecfg->find_func) {
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int i;
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struct ff_regs *regs = xecfg->find_func_priv;
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for (i = 0; i < regs->nr; i++)
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regfree(®s->array[i].re);
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free(regs->array);
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free(regs);
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xecfg->find_func = NULL;
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xecfg->find_func_priv = NULL;
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}
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}
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unsigned long xdiff_hash_string(const char *s, size_t len, long flags)
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{
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return xdl_hash_record(&s, s + len, flags);
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}
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int xdiff_compare_lines(const char *l1, long s1,
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const char *l2, long s2, long flags)
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{
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return xdl_recmatch(l1, s1, l2, s2, flags);
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}
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int git_xmerge_style = -1;
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int git_xmerge_config(const char *var, const char *value, void *cb)
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{
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if (!strcmp(var, "merge.conflictstyle")) {
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if (!value)
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die("'%s' is not a boolean", var);
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if (!strcmp(value, "diff3"))
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git_xmerge_style = XDL_MERGE_DIFF3;
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else if (!strcmp(value, "merge"))
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git_xmerge_style = 0;
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/*
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* Please update _git_checkout() in
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* git-completion.bash when you add new merge config
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*/
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else
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die("unknown style '%s' given for '%s'",
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value, var);
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return 0;
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}
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return git_default_config(var, value, cb);
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}
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