perf tools: Move help_unknown_cmd() to its own file

help_unknown_cmd() is quite perf-specific because it relies on some
perf_config*() functions.  Move it and its supporting functions out into
a separate file so that help.c can be moved to a library.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/562d918bcaaf340c1ae3e47586b3f0ae33b9918b.1449965119.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 103 insertions, 0 deletions

diff --git a/tools/perf/util/help-unknown-cmd.c b/tools/perf/util/help-unknown-cmd.c
new file mode 100644
index 000000000000..a0820f16f511
--- /dev/null
+++ b/tools/perf/util/help-unknown-cmd.c
@@ -0,0 +1,103 @@
+#include "cache.h"
+#include "help.h"
+#include "../builtin.h"
+#include "levenshtein.h"
+
+static int autocorrect;
+static struct cmdnames aliases;
+
+static int perf_unknown_cmd_config(const char *var, const char *value, void *cb)
+{
+        if (!strcmp(var, "help.autocorrect"))
+                autocorrect = perf_config_int(var,value);
+        /* Also use aliases for command lookup */
+        if (!prefixcmp(var, "alias."))
+                add_cmdname(&aliases, var + 6, strlen(var + 6));
+
+        return perf_default_config(var, value, cb);
+}
+
+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);
+}
+
+static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
+{
+        unsigned int i;
+
+        ALLOC_GROW(cmds->names, cmds->cnt + old->cnt, cmds->alloc);
+
+        for (i = 0; i < old->cnt; i++)
+                cmds->names[cmds->cnt++] = old->names[i];
+        zfree(&old->names);
+        old->cnt = 0;
+}
+
+const char *help_unknown_cmd(const char *cmd)
+{
+        unsigned int i, n = 0, best_similarity = 0;
+        struct cmdnames main_cmds, other_cmds;
+
+        memset(&main_cmds, 0, sizeof(main_cmds));
+        memset(&other_cmds, 0, sizeof(main_cmds));
+        memset(&aliases, 0, sizeof(aliases));
+
+        perf_config(perf_unknown_cmd_config, NULL);
+
+        load_command_list("perf-", &main_cmds, &other_cmds);
+
+        add_cmd_list(&main_cmds, &aliases);
+        add_cmd_list(&main_cmds, &other_cmds);
+        qsort(main_cmds.names, main_cmds.cnt,
+              sizeof(main_cmds.names), cmdname_compare);
+        uniq(&main_cmds);
+
+        if (main_cmds.cnt) {
+                /* 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);
+
+                best_similarity = main_cmds.names[0]->len;
+                n = 1;
+                while (n < main_cmds.cnt && best_similarity == main_cmds.names[n]->len)
+                        ++n;
+        }
+
+        if (autocorrect && 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 perf program named '%s', "
+                        "which does not exist.\n"
+                        "Continuing under the assumption that you meant '%s'\n",
+                        cmd, assumed);
+                if (autocorrect > 0) {
+                        fprintf(stderr, "in %0.1f seconds automatically...\n",
+                                (float)autocorrect/10.0);
+                        poll(NULL, 0, autocorrect * 100);
+                }
+                return assumed;
+        }
+
+        fprintf(stderr, "perf: '%s' is not a perf-command. See 'perf --help'.\n", cmd);
+
+        if (main_cmds.cnt && 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);
+}