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authorJohannes Schindelin <Johannes.Schindelin@gmx.de>2008-08-31 13:50:23 (GMT)
committerJunio C Hamano <gitster@pobox.com>2008-08-31 17:14:58 (GMT)
commit8af84dadb142f7321ff0ce8690385e99da8ede2f (patch)
treee47023679099de35b18da39c3b1c89efc0dd2c3a /help.c
parenta1184d85e8752658f02746982822f43f32316803 (diff)
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git wrapper: DWIM mistyped commands
This patch introduces a modified Damerau-Levenshtein algorithm into Git's code base, and uses it with the following penalties to show some similar commands when an unknown command was encountered: swap = 0, insertion = 1, substitution = 2, deletion = 4 A typical output would now look like this: $ git sm git: 'sm' is not a git-command. See 'git --help'. Did you mean one of these? am rm The cut-off is at similarity rating 6, which was empirically determined to give sensible results. As a convenience, if there is only one candidate, Git continues under the assumption that the user mistyped it. Example: $ git reabse WARNING: You called a Git program named 'reabse', which does not exist. Continuing under the assumption that you meant 'rebase' [...] Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Alex Riesen <raa.lkml@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'help.c')
-rw-r--r--help.c72
1 files changed, 71 insertions, 1 deletions
diff --git a/help.c b/help.c
index 1afbac0..b1ebca4 100644
--- a/help.c
+++ b/help.c
@@ -1,6 +1,7 @@
#include "cache.h"
#include "builtin.h"
#include "exec_cmd.h"
+#include "levenshtein.h"
#include "help.h"
/* most GUI terminals set COLUMNS (although some don't export it) */
@@ -37,6 +38,16 @@ void add_cmdname(struct cmdnames *cmds, const char *name, int len)
cmds->names[cmds->cnt++] = ent;
}
+static void clean_cmdnames(struct cmdnames *cmds)
+{
+ int i;
+ for (i = 0; i < cmds->cnt; ++i)
+ free(cmds->names[i]);
+ free(cmds->names);
+ cmds->cnt = 0;
+ cmds->alloc = 0;
+}
+
static int cmdname_compare(const void *a_, const void *b_)
{
struct cmdname *a = *(struct cmdname **)a_;
@@ -257,9 +268,68 @@ int is_in_cmdlist(struct cmdnames *c, const char *s)
return 0;
}
-void help_unknown_cmd(const char *cmd)
+static int levenshtein_compare(const void *p1, const void *p2)
+{
+ const struct cmdname *const *c1 = p1, *const *c2 = p2;
+ const char *s1 = (*c1)->name, *s2 = (*c2)->name;
+ int l1 = (*c1)->len;
+ int l2 = (*c2)->len;
+ return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
+}
+
+const char *help_unknown_cmd(const char *cmd)
{
+ int i, n, best_similarity = 0;
+ struct cmdnames main_cmds, other_cmds;
+
+ memset(&main_cmds, 0, sizeof(main_cmds));
+ memset(&other_cmds, 0, sizeof(main_cmds));
+
+ load_command_list("git-", &main_cmds, &other_cmds);
+
+ ALLOC_GROW(main_cmds.names, main_cmds.cnt + other_cmds.cnt,
+ main_cmds.alloc);
+ memcpy(main_cmds.names + main_cmds.cnt, other_cmds.names,
+ other_cmds.cnt * sizeof(other_cmds.names[0]));
+ main_cmds.cnt += other_cmds.cnt;
+ free(other_cmds.names);
+
+ /* This reuses cmdname->len for similarity index */
+ for (i = 0; i < main_cmds.cnt; ++i)
+ main_cmds.names[i]->len =
+ levenshtein(cmd, main_cmds.names[i]->name, 0, 2, 1, 4);
+
+ qsort(main_cmds.names, main_cmds.cnt,
+ sizeof(*main_cmds.names), levenshtein_compare);
+
+ if (!main_cmds.cnt)
+ die ("Uh oh. Your system reports no Git commands at all.");
+
+ best_similarity = main_cmds.names[0]->len;
+ n = 1;
+ while (n < main_cmds.cnt && best_similarity == main_cmds.names[n]->len)
+ ++n;
+ if (n == 1) {
+ const char *assumed = main_cmds.names[0]->name;
+ main_cmds.names[0] = NULL;
+ clean_cmdnames(&main_cmds);
+ fprintf(stderr, "WARNING: You called a Git program named '%s', "
+ "which does not exist.\n"
+ "Continuing under the assumption that you meant '%s'\n",
+ cmd, assumed);
+ return assumed;
+ }
+
fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
+
+ if (best_similarity < 6) {
+ fprintf(stderr, "\nDid you mean %s?\n",
+ n < 2 ? "this": "one of these");
+
+ for (i = 0; i < n; i++)
+ fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
+ }
+
exit(1);
}