xdiff: remove xemit related logic

xemit handles "diff formatting and output" with options like context lines,
whether show function names, etc. That is handled more cleanly at a higher
level in hg.

Removing context line parameters would also make the trimming logic (D2686)
cleaner and more confident. See [1].

[1]: https://github.com/git/git/commit/d2f82950a9226ae1102a7a97f03440a4bf8c6c09

Differential Revision: https://phab.mercurial-scm.org/D2705

mercurial/cext/bdiff.c

@@ -280,16 +280,11 b' static PyObject *xdiffblocks(PyObject *s'
 	    XDF_INDENT_HEURISTIC, /* flags */
 	};
 	xdemitconf_t xecfg = {
-	    0,                  /* ctxlen */
-	    0,                  /* interhunkctxlen */
 	    XDL_EMIT_BDIFFHUNK, /* flags */
-	    NULL,               /* find_func */
-	    NULL,               /* find_func_priv */
 	    hunk_consumer,      /* hunk_consume_func */
 	};
 	xdemitcb_t ecb = {
 	    NULL, /* priv */
-	    NULL, /* outf */
 	};
 
 	if (!PyArg_ParseTuple(args, PY23("s#s#", "y#y#"), &a.ptr, &la, &b.ptr,

mercurial/thirdparty/xdiff/xdiff.h

@@ -34,9 +34,6 b' extern "C" {'
 
 #define XDF_INDENT_HEURISTIC (1 << 23)
 
-/* xdemitconf_t.flags */
-#define XDL_EMIT_FUNCNAMES (1 << 0)
-#define XDL_EMIT_FUNCCONTEXT (1 << 2)
 /* emit bdiff-style "matched" (a1, a2, b1, b2) hunks instead of "different"
  * (a1, a2 - a1, b1, b2 - b1) hunks */
 #define XDL_EMIT_BDIFFHUNK (1 << 4)
@@ -71,21 +68,14 b' typedef struct s_xpparam {'
 
 typedef struct s_xdemitcb {
 	void *priv;
-	int (*outf)(void *, mmbuffer_t *, int);
 } xdemitcb_t;
 
-typedef long (*find_func_t)(const char *line, long line_len, char *buffer, long buffer_size, void *priv);
-
 typedef int (*xdl_emit_hunk_consume_func_t)(long start_a, long count_a,
 					    long start_b, long count_b,
 					    void *cb_data);
 
 typedef struct s_xdemitconf {
-	long ctxlen;
-	long interhunkctxlen;
 	unsigned long flags;
-	find_func_t find_func;
-	void *find_func_priv;
 	xdl_emit_hunk_consume_func_t hunk_func;
 } xdemitconf_t;
 

mercurial/thirdparty/xdiff/xdiffi.c

@@ -1007,10 +1007,66 b' void xdl_free_script(xdchange_t *xscr) {'
 	}
 }
 
+
+/*
+ * Starting at the passed change atom, find the latest change atom to be included
+ * inside the differential hunk according to the specified configuration.
+ * Also advance xscr if the first changes must be discarded.
+ */
+xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
+{
+	xdchange_t *xch, *xchp, *lxch;
+	long max_common = 0;
+	long max_ignorable = 0;
+	unsigned long ignored = 0; /* number of ignored blank lines */
+
+	/* remove ignorable changes that are too far before other changes */
+	for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
+		xch = xchp->next;
+
+		if (xch == NULL ||
+		    xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
+			*xscr = xch;
+	}
+
+	if (*xscr == NULL)
+		return NULL;
+
+	lxch = *xscr;
+
+	for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
+		long distance = xch->i1 - (xchp->i1 + xchp->chg1);
+		if (distance > max_common)
+			break;
+
+		if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
+			lxch = xch;
+			ignored = 0;
+		} else if (distance < max_ignorable && xch->ignore) {
+			ignored += xch->chg2;
+		} else if (lxch != xchp &&
+			   xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
+			break;
+		} else if (!xch->ignore) {
+			lxch = xch;
+			ignored = 0;
+		} else {
+			ignored += xch->chg2;
+		}
+	}
+
+	return lxch;
+}
+
+
 static int xdl_call_hunk_func(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 			      xdemitconf_t const *xecfg)
 {
 	xdchange_t *xch, *xche;
+
+	if (!xecfg->hunk_func)
+		return -1;
+
 	if ((xecfg->flags & XDL_EMIT_BDIFFHUNK) != 0) {
 		long i1 = 0, i2 = 0, n1 = xe->xdf1.nrec, n2 = xe->xdf2.nrec;
 		for (xch = xscr; xch; xch = xche->next) {
@@ -1045,7 +1101,6 b' int xdl_diff(mmfile_t *mf1, mmfile_t *mf'
 	     xdemitconf_t const *xecfg, xdemitcb_t *ecb) {
 	xdchange_t *xscr;
 	xdfenv_t xe;
-	emit_func_t ef = xecfg->hunk_func ? xdl_call_hunk_func : xdl_emit_diff;
 
 	if (xdl_do_diff(mf1, mf2, xpp, &xe) < 0) {
 
@@ -1059,7 +1114,7 b' int xdl_diff(mmfile_t *mf1, mmfile_t *mf'
 		return -1;
 	}
 
-	if (ef(&xe, xscr, ecb, xecfg) < 0) {
+	if (xdl_call_hunk_func(&xe, xscr, ecb, xecfg) < 0) {
 		xdl_free_script(xscr);
 		xdl_free_env(&xe);
 		return -1;

mercurial/thirdparty/xdiff/xdiffi.h

@@ -54,7 +54,5 b' int xdl_do_diff(mmfile_t *mf1, mmfile_t '
 int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags);
 int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr);
 void xdl_free_script(xdchange_t *xscr);
-int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
-		  xdemitconf_t const *xecfg);
 
 #endif /* #if !defined(XDIFFI_H) */

mercurial/thirdparty/xdiff/xinclude.h

@@ -35,7 +35,6 b''
 #include "xutils.h"
 #include "xprepare.h"
 #include "xdiffi.h"
-#include "xemit.h"
 
 
 #endif /* #if !defined(XINCLUDE_H) */

mercurial/thirdparty/xdiff/xutils.c

@@ -40,28 +40,6 b' long xdl_bogosqrt(long n) {'
 }
 
 
-int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
-		     xdemitcb_t *ecb) {
-	int i = 2;
-	mmbuffer_t mb[3];
-
-	mb[0].ptr = (char *) pre;
-	mb[0].size = psize;
-	mb[1].ptr = (char *) rec;
-	mb[1].size = size;
-	if (size > 0 && rec[size - 1] != '\n') {
-		mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
-		mb[2].size = strlen(mb[2].ptr);
-		i++;
-	}
-	if (ecb->outf(ecb->priv, mb, i) < 0) {
-
-		return -1;
-	}
-
-	return 0;
-}
-
 void *xdl_mmfile_first(mmfile_t *mmf, long *size)
 {
 	*size = mmf->size;
@@ -169,75 +147,3 b' unsigned int xdl_hashbits(unsigned int s'
 	for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
 	return bits ? bits: 1;
 }
-
-
-int xdl_num_out(char *out, long val) {
-	char *ptr, *str = out;
-	char buf[32];
-
-	ptr = buf + sizeof(buf) - 1;
-	*ptr = '\0';
-	if (val < 0) {
-		*--ptr = '-';
-		val = -val;
-	}
-	for (; val && ptr > buf; val /= 10)
-		*--ptr = "0123456789"[val % 10];
-	if (*ptr)
-		for (; *ptr; ptr++, str++)
-			*str = *ptr;
-	else
-		*str++ = '0';
-	*str = '\0';
-
-	return str - out;
-}
-
-int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
-		      const char *func, long funclen, xdemitcb_t *ecb) {
-	int nb = 0;
-	mmbuffer_t mb;
-	char buf[128];
-
-	memcpy(buf, "@@ -", 4);
-	nb += 4;
-
-	nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
-
-	if (c1 != 1) {
-		memcpy(buf + nb, ",", 1);
-		nb += 1;
-
-		nb += xdl_num_out(buf + nb, c1);
-	}
-
-	memcpy(buf + nb, " +", 2);
-	nb += 2;
-
-	nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
-
-	if (c2 != 1) {
-		memcpy(buf + nb, ",", 1);
-		nb += 1;
-
-		nb += xdl_num_out(buf + nb, c2);
-	}
-
-	memcpy(buf + nb, " @@", 3);
-	nb += 3;
-	if (func && funclen) {
-		buf[nb++] = ' ';
-		if (funclen > sizeof(buf) - nb - 1)
-			funclen = sizeof(buf) - nb - 1;
-		memcpy(buf + nb, func, funclen);
-		nb += funclen;
-	}
-	buf[nb++] = '\n';
-
-	mb.ptr = buf;
-	mb.size = nb;
-	if (ecb->outf(ecb->priv, &mb, 1) < 0)
-		return -1;
-
-	return 0;
-}

mercurial/thirdparty/xdiff/xutils.h

@@ -26,8 +26,6 b''
 
 
 long xdl_bogosqrt(long n);
-int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
-		     xdemitcb_t *ecb);
 int xdl_cha_init(chastore_t *cha, long isize, long icount);
 void xdl_cha_free(chastore_t *cha);
 void *xdl_cha_alloc(chastore_t *cha);
@@ -35,9 +33,6 b' long xdl_guess_lines(mmfile_t *mf, long '
 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags);
 unsigned long xdl_hash_record(char const **data, char const *top, long flags);
 unsigned int xdl_hashbits(unsigned int size);
-int xdl_num_out(char *out, long val);
-int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
-		      const char *func, long funclen, xdemitcb_t *ecb);
 
 
 

setup.py

@@ -850,7 +850,6 b" if sys.platform == 'darwin':"
 
 xdiff_srcs = [
     'mercurial/thirdparty/xdiff/xdiffi.c',
-    'mercurial/thirdparty/xdiff/xemit.c',
     'mercurial/thirdparty/xdiff/xmerge.c',
     'mercurial/thirdparty/xdiff/xprepare.c',
     'mercurial/thirdparty/xdiff/xutils.c',
@@ -859,7 +858,6 b' xdiff_srcs = ['
 xdiff_headers = [
     'mercurial/thirdparty/xdiff/xdiff.h',
     'mercurial/thirdparty/xdiff/xdiffi.h',
-    'mercurial/thirdparty/xdiff/xemit.h',
     'mercurial/thirdparty/xdiff/xinclude.h',
     'mercurial/thirdparty/xdiff/xmacros.h',
     'mercurial/thirdparty/xdiff/xprepare.h',