Appologies for gmail mangling. I will use git send-email for real patches.
On Tue, Oct 14, 2008 at 6:44 PM, Stefan Karpinski
<stefan.karpinski@xxxxxxxxx> wrote:
> I find myself really wanting to enforce standards in the use of spaces
> versus tabs. I deal with some unruly programmers who refuse to set
> their editors to use soft tabs, but I *hate* tabs in the repo. And of
> course others feel equally strongly about keeping only tabs in the
> repo (e.g. the git repo).
>
> This led me to wonder if it wouldn't make sense to have this
> conversion ability built into git. The following patch implements this
> functionality. It still needs work—it's not meant to be final, just to
> give an idea—but I just wanted to see if people on the git list
> thought this sort of thing would be worthwhile at all.
>
> If people think it's worth having in git, then how should it be
> configured? I feel like a project should be able to define the
> expected tab size for binary file types. Moreover, the project should
> be able to define the default cannonicalization with resepect to
> whitespace for different files types. Then, if they so desire, each
> git user should be able to override the output format on a
> per-repository basis.
>
> Does this make any sense? Comments?
>
> ---
> diff --git a/convert.c b/convert.c
> index 1816e97..280f45b 100644
> --- a/convert.c
> +++ b/convert.c
> @@ -18,7 +18,7 @@
>
> struct text_stat {
> /* NUL, CR, LF and CRLF counts */
> - unsigned nul, cr, lf, crlf;
> + unsigned nul, cr, lf, crlf, tab;
>
> /* These are just approximations! */
> unsigned printable, nonprintable;
> @@ -48,7 +48,10 @@
> static void gather_stats(const char *buf, unsigned long size, struct
> text_stat *
> else if (c < 32) {
> switch (c) {
> /* BS, HT, ESC and FF */
> - case '\b': case '\t': case '\033': case '\014':
> + case '\t':
> + stats->tab++;
> + /* fall through */
> + case '\b': case '\033': case '\014':
> stats->printable++;
> break;
> case 0:
> @@ -235,6 +238,105 @@
> static int crlf_to_worktree(const char *path, const char *src, size_t len,
> return 1;
> }
>
> +static int tabs_to_spaces(const char *path, const char *src, size_t len,
> +
> struct strbuf *buf, int untabify)
> +{
> + char *to_free = NULL;
> + struct text_stat stats;
> + static const unsigned tab_size = 4;
> + char *spaces;
> +
> + if (!untabify)
> + return 0;
> +
> + /* instead of calling twice, should cache these stats across calls */
> + gather_stats(src, len, &stats);
> +
> + if (!stats.tab)
> + return 0;
> +
> + /* are we "faking" in place editing ? */
> + if (src == buf->buf)
> + to_free = strbuf_detach(buf, NULL);
> +
> + /* this growth may be excessive: not all tabs get tab_size spaces */
> + strbuf_grow(buf, len + tab_size * stats.tab);
> + spaces = (char *) xmalloc(tab_size);
> + memset(spaces, ' ', tab_size);
> + for (;;) {
> + const char *line = src;
> + const char *nl = memchr(src, '\n', len);
> + char *tab;
> + if (!nl)
> + nl = src + len;
> + while (src < nl && (tab = memchr(src, '\t', nl - src))) {
> + strbuf_add(buf, src, tab - src);
> + strbuf_add(buf, spaces, tab_size - ((tab - line) % tab_size));
> + src = tab + 1;
> + }
> + if (src < nl)
> + strbuf_add(buf, src, nl - src);
> + if (nl < src + len)
> + strbuf_addch(buf, '\n');
> + else
> + break;
> + src = nl + 1;
> + len -= src - line;
> + }
> +
> + free(to_free);
> + free(spaces);
> + return 1;
> +}
> +
> +static int spaces_to_tabs(const char *path, const char *src, size_t len,
> +
> struct strbuf *buf, int tabify)
> +{
> + static const unsigned tab_size = 4;
> +
> + if (!tabify)
> + return 0;
> +
> + /* only grow if not in place */
> + if (strbuf_avail(buf) + buf->len < len)
> + strbuf_grow(buf, len - buf->len);
> +
> + for (;;) {
> + int tabs = 0, spaces = 0;
> + const char *line = src;
> + const char *nl = memchr(src, '\n', len);
> + if (!nl)
> + nl = src + len;
> + for (;; src++) {
> + if (*src == ' ') {
> + spaces++;
> + if (spaces == tab_size) {
> + tabs++;
> + spaces = 0;
> + }
> + } else if (*src == '\t') {
> + tabs++;
> + spaces = 0;
> + } else break;
> + }
> + if (line < src) {
> + memset(buf->buf + buf->len, '\t', tabs);
> + memset(buf->buf + buf->len + tabs, ' ', spaces);
> + strbuf_setlen(buf, buf->len + tabs + spaces);
> + }
> + if (src < nl)
> + strbuf_add(buf, src, nl - src);
> + if (nl < src + len)
> + strbuf_addch(buf, '\n');
> + else
> + break;
> + src = nl + 1;
> + len -= src - line;
> + }
> +
> + return 1;
> +}
> +
> struct filter_params {
> const char *src;
> unsigned long size;
> @@ -370,22 +472,29 @@
> static int read_convert_config(const char *var, const char *value, void *cb)
> return 0;
> }
>
> -static void setup_convert_check(struct git_attr_check *check)
> +struct convert_checks {
> + struct git_attr_check crlf, tabs, ident, filter;
> +};
> +
> +static void setup_convert_check(struct convert_checks *checks)
> {
> static struct git_attr *attr_crlf;
> + static struct git_attr *attr_tabs;
> static struct git_attr *attr_ident;
> static struct git_attr *attr_filter;
>
> if (!attr_crlf) {
> attr_crlf = git_attr("crlf", 4);
> + attr_tabs = git_attr("tabs", 4);
> attr_ident = git_attr("ident", 5);
> attr_filter = git_attr("filter", 6);
> user_convert_tail = &user_convert;
> git_config(read_convert_config, NULL);
> }
> - check[0].attr = attr_crlf;
> - check[1].attr = attr_ident;
> - check[2].attr = attr_filter;
> + checks->crlf.attr = attr_crlf;
> + checks->tabs.attr = attr_tabs;
> + checks->ident.attr = attr_ident;
> + checks->filter.attr = attr_filter;
> }
>
> static int count_ident(const char *cp, unsigned long size)
> @@ -566,20 +675,22 @@
> static int git_path_check_ident(const char *path, struct git_attr_check *check)
> return !!ATTR_TRUE(value);
> }
>
> +#define CHECK_ARRAY_SIZE (sizeof(struct convert_checks)/sizeof(struct
> git_attr_check))
> +
> int convert_to_git(const char *path, const char *src, size_t len,
> struct strbuf *dst, enum safe_crlf checksafe)
> {
> - struct git_attr_check check[3];
> + struct convert_checks checks;
> int crlf = CRLF_GUESS;
> int ident = 0, ret = 0;
> const char *filter = NULL;
>
> - setup_convert_check(check);
> - if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
> + setup_convert_check(&checks);
> + if (!git_checkattr(path, CHECK_ARRAY_SIZE, (struct git_attr_check *)
> &checks)) {
> struct convert_driver *drv;
> - crlf = git_path_check_crlf(path, check + 0);
> - ident = git_path_check_ident(path, check + 1);
> - drv = git_path_check_convert(path, check + 2);
> + crlf = git_path_check_crlf(path, &(checks.crlf));
> + ident = git_path_check_ident(path, &(checks.ident));
> + drv = git_path_check_convert(path, &(checks.filter));
> if (drv && drv->clean)
> filter = drv->clean;
> }
> @@ -589,6 +700,11 @@
> int convert_to_git(const char *path, const char *src, size_t len,
> src = dst->buf;
> len = dst->len;
> }
> + ret |= tabs_to_spaces(path, src, len, dst, 1); // get real variable
> + if (ret) {
> + src = dst->buf;
> + len = dst->len;
> + }
> ret |= crlf_to_git(path, src, len, dst, crlf, checksafe);
> if (ret) {
> src = dst->buf;
> @@ -599,17 +715,17 @@
> int convert_to_git(const char *path, const char *src, size_t len,
>
> int convert_to_working_tree(const char *path, const char *src, size_t
> len, struct strbuf *dst)
> {
> - struct git_attr_check check[3];
> + struct convert_checks checks;
> int crlf = CRLF_GUESS;
> int ident = 0, ret = 0;
> const char *filter = NULL;
>
> - setup_convert_check(check);
> - if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
> + setup_convert_check(&checks);
> + if (!git_checkattr(path, CHECK_ARRAY_SIZE, (struct git_attr_check *)
> &checks)) {
> struct convert_driver *drv;
> - crlf = git_path_check_crlf(path, check + 0);
> - ident = git_path_check_ident(path, check + 1);
> - drv = git_path_check_convert(path, check + 2);
> + crlf = git_path_check_crlf(path, &(checks.crlf));
> + ident = git_path_check_ident(path, &(checks.ident));
> + drv = git_path_check_convert(path, &(checks.filter));
> if (drv && drv->smudge)
> filter = drv->smudge;
> }
> @@ -624,5 +740,10 @@
> int convert_to_working_tree(const char *path, const char *src, size_t
> len, struc
> src = dst->buf;
> len = dst->len;
> }
> + ret |= tabs_to_spaces(path, src, len, dst, 1); // get real variable
> + if (ret) {
> + src = dst->buf;
> + len = dst->len;
> + }
> return ret | apply_filter(path, src, len, dst, filter);
> }
>
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