view mercurial/bdiff.h @ 29837:5b886289a1ca

formatter: add fm.nested(field) to either write or build sub items

We sometimes need to build nested items by formatter, but there was no
convenient way other than building and putting them manually by fm.data():

  exts = []
  for n, v in extensions:
      fm.plain('%s %s\n' % (n, v))
      exts.append({'name': n, 'ver': v})
  fm.data(extensions=exts)

This should work for simple cases, but doing this would make it harder to
change the underlying data type for better templating support.

So this patch provides fm.nested(field), which returns new nested formatter
(or self if items aren't structured and just written to ui.) A nested formatter
stores items which will later be rendered by the parent formatter.

  fn = fm.nested('extensions')
  for n, v in extensions:
      fn.startitem()
      fn.write('name ver', '%s %s\n', n, v)
  fn.end()

Nested items are directly exported to a template for now:

  {extensions % "{name} {ver}\n"}

There's no {extensions} nor {join(extensions, sep)} yet. I have a plan for
them by extending fm.nested() API, but I want to revisit it after trying
out this API in the real world.

#ifndef _HG_BDIFF_H_
#define _HG_BDIFF_H_

struct bdiff_line {
	int hash, n, e;
	ssize_t len;
	const char *l;
};

struct bdiff_hunk;
struct bdiff_hunk {
	int a1, a2, b1, b2;
	struct bdiff_hunk *next;
};

int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);
int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,
	struct bdiff_hunk *base);
void bdiff_freehunks(struct bdiff_hunk *l);

#endif