Implements a new syntax @{-N} that parses the reflog for the N-th last interesting 'checkout: moving from $branch to $new' entry and substitutes $branch. Here, "interesting" is defined as $branch != $new. We then substitute the real branch name for the parse. For example: git checkout foo git checkout bar git checkout master git checkout master # did not move, so doesn't count git rev-parse @{-1} # same as bar git rev-parse @{-2} # same as foo git rev-parse @{-2}~3 # same as foo~3 Thanks to Junio for much of the code. Signed-off-by: Thomas Rast <trast@xxxxxxxxxxxxxxx> --- Documentation/git-rev-parse.txt | 3 + cache.h | 1 + sha1_name.c | 99 +++++++++++++++++++++++++++++++++++++- t/t1505-rev-parse-last.sh | 71 ++++++++++++++++++++++++++++ 4 files changed, 171 insertions(+), 3 deletions(-) create mode 100755 t/t1505-rev-parse-last.sh diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt index 2921da3..3ccef2f 100644 --- a/Documentation/git-rev-parse.txt +++ b/Documentation/git-rev-parse.txt @@ -212,6 +212,9 @@ when you run 'git-merge'. reflog of the current branch. For example, if you are on the branch 'blabla', then '@\{1\}' means the same as 'blabla@\{1\}'. +* The special construct '@\{-<n>\}' means the <n>th branch checked out + before the current one. + * A suffix '{caret}' to a revision parameter means the first parent of that commit object. '{caret}<n>' means the <n>th parent (i.e. 'rev{caret}' diff --git a/cache.h b/cache.h index 8e1af26..0dd9168 100644 --- a/cache.h +++ b/cache.h @@ -663,6 +663,7 @@ static inline unsigned int hexval(unsigned char c) extern const char *resolve_ref(const char *path, unsigned char *sha1, int, int *); extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref); extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref); +extern int interpret_nth_last_branch(const char *str, struct strbuf *); extern int refname_match(const char *abbrev_name, const char *full_name, const char **rules); extern const char *ref_rev_parse_rules[]; diff --git a/sha1_name.c b/sha1_name.c index 159c2ab..9e1538e 100644 --- a/sha1_name.c +++ b/sha1_name.c @@ -297,6 +297,8 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log) return logs_found; } +static int get_sha1_1(const char *name, int len, unsigned char *sha1); + static int get_sha1_basic(const char *str, int len, unsigned char *sha1) { static const char *warning = "warning: refname '%.*s' is ambiguous.\n"; @@ -307,7 +309,7 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1) if (len == 40 && !get_sha1_hex(str, sha1)) return 0; - /* basic@{time or number} format to query ref-log */ + /* basic@{time or number or -number} format to query ref-log */ reflog_len = at = 0; if (str[len-1] == '}') { for (at = 0; at < len - 1; at++) { @@ -324,6 +326,16 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1) return -1; if (!len && reflog_len) { + struct strbuf buf = STRBUF_INIT; + int ret; + /* try the @{-N} syntax for n-th checkout */ + ret = interpret_nth_last_branch(str+at, &buf); + if (ret > 0) { + /* substitute this branch name and restart */ + return get_sha1_1(buf.buf, buf.len, sha1); + } else if (ret == 0) { + return -1; + } /* allow "@{...}" to mean the current branch reflog */ refs_found = dwim_ref("HEAD", 4, sha1, &real_ref); } else if (reflog_len) @@ -379,8 +391,6 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1) return 0; } -static int get_sha1_1(const char *name, int len, unsigned char *sha1); - static int get_parent(const char *name, int len, unsigned char *result, int idx) { @@ -674,6 +684,89 @@ static int get_sha1_oneline(const char *prefix, unsigned char *sha1) return retval; } +struct grab_nth_branch_switch_cbdata { + int counting; + int nth; + struct strbuf *buf; +}; + +static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1, + const char *email, unsigned long timestamp, int tz, + const char *message, void *cb_data) +{ + struct grab_nth_branch_switch_cbdata *cb = cb_data; + const char *match = NULL, *target = NULL; + size_t len; + + if (!prefixcmp(message, "checkout: moving from ")) { + match = message + strlen("checkout: moving from "); + if ((target = strstr(match, " to ")) != NULL) + target += 4; + } + + if (!match) + return 0; + + len = target - match - 4; + if (target[len] == '\n' && !strncmp(match, target, len)) + return 0; + + if (cb->counting) { + cb->nth++; + return 0; + } + + if (cb->nth-- <= 0) { + strbuf_reset(cb->buf); + strbuf_add(cb->buf, match, len); + return 1; + } + return 0; +} + +/* + * This reads "@{-N}" syntax, finds the name of the Nth previous + * branch we were on, and places the name of the branch in the given + * buf and returns the number of characters parsed if successful. + * + * If the input is not of the accepted format, it returns a negative + * number to signal an error. + * + * If the input was ok but there are not N branch switches in the + * reflog, it returns 0. + */ +int interpret_nth_last_branch(const char *name, struct strbuf *buf) +{ + int nth; + struct grab_nth_branch_switch_cbdata cb; + const char *brace; + char *num_end; + + if (name[0] != '@' || name[1] != '{' || name[2] != '-') + return -1; + brace = strchr(name, '}'); + if (!brace) + return -1; + nth = strtol(name+3, &num_end, 10); + if (num_end != brace) + return -1; + + cb.counting = 1; + cb.nth = 0; + cb.buf = buf; + for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb); + + if (cb.nth < nth) + return 0; + + cb.counting = 0; + cb.nth -= nth; + cb.buf = buf; + for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb); + + return brace-name+1; +} + /* * This is like "get_sha1_basic()", except it allows "sha1 expressions", * notably "xyz^" for "parent of xyz" diff --git a/t/t1505-rev-parse-last.sh b/t/t1505-rev-parse-last.sh new file mode 100755 index 0000000..1e49dd2 --- /dev/null +++ b/t/t1505-rev-parse-last.sh @@ -0,0 +1,71 @@ +#!/bin/sh + +test_description='test @{-N} syntax' + +. ./test-lib.sh + + +make_commit () { + echo "$1" > "$1" && + git add "$1" && + git commit -m "$1" +} + + +test_expect_success 'setup' ' + + make_commit 1 && + git branch side && + make_commit 2 && + make_commit 3 && + git checkout side && + make_commit 4 && + git merge master && + git checkout master + +' + +# 1 -- 2 -- 3 master +# \ \ +# \ \ +# --- 4 --- 5 side +# +# and 'side' should be the last branch + +git log --graph --all --pretty=oneline --decorate + +test_rev_equivalent () { + + git rev-parse "$1" > expect && + git rev-parse "$2" > output && + test_cmp expect output + +} + +test_expect_success '@{-1} works' ' + test_rev_equivalent side @{-1} +' + +test_expect_success '@{-1}~2 works' ' + test_rev_equivalent side~2 @{-1}~2 +' + +test_expect_success '@{-1}^2 works' ' + test_rev_equivalent side^2 @{-1}^2 +' + +test_expect_failure '@{-1}@{1} works' ' + test_rev_equivalent side@{1} @{-1}@{1} +' + +test_expect_success '@{-2} works' ' + test_rev_equivalent master @{-2} +' + +test_expect_success '@{-3} fails' ' + test_must_fail git rev-parse @{-3} +' + +test_done + + -- 1.6.1.315.g92577 -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html