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authorPřemysl Janouch <p@janouch.name>2018-11-01 15:54:32 +0100
committerPřemysl Janouch <p@janouch.name>2018-11-01 16:03:17 +0100
commit292829852eb462f45ae0da0b2370992f29b3ee77 (patch)
treeda15f59a38760d7dd57dbee42650d49925bf7d0e
parentdb051698e655651efcdcd502e7422699dbdf419a (diff)
downloadsdn-292829852eb462f45ae0da0b2370992f29b3ee77.tar.gz
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sdn-292829852eb462f45ae0da0b2370992f29b3ee77.zip
Implement simple in-application help
It could be made more complicated but I guess it's fine for now. We've learnt to run pagers.
-rw-r--r--sdn.cpp119
1 files changed, 111 insertions, 8 deletions
diff --git a/sdn.cpp b/sdn.cpp
index b3b8051..bd71a50 100644
--- a/sdn.cpp
+++ b/sdn.cpp
@@ -41,6 +41,8 @@
#include <sys/inotify.h>
#include <sys/xattr.h>
+#include <sys/types.h>
+#include <sys/wait.h>
#include <acl/libacl.h>
#include <ncurses.h>
@@ -155,6 +157,21 @@ template<class T> fun shift (vector<T> &v) -> T {
auto front = v.front (); v.erase (begin (v)); return front;
}
+fun capitalize (const string &s) -> string {
+ string result;
+ for (auto c : s)
+ result += result.empty () ? toupper (c) : tolower (c);
+ return result;
+}
+
+/// Underlining for teletypes, also imitated in more(1) and less(1)
+fun underline (const string& s) -> string {
+ string result;
+ for (auto c : s)
+ result.append ({c, 8, '_'});
+ return result;
+}
+
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
fun xdg_config_home () -> string {
@@ -233,6 +250,13 @@ fun print (const ncstring &nc, int limit) -> int {
return total_width;
}
+fun compute_width (const wstring &w) -> int {
+ int total = 0;
+ for (const auto &c : w)
+ total += wcwidth (c);
+ return total;
+}
+
fun compute_width (const ncstring &nc) -> int {
int total = 0;
for (const auto &c : nc)
@@ -295,7 +319,7 @@ struct entry {
}
};
-#define ACTIONS(XX) XX(NONE) XX(CHOOSE) XX(CHOOSE_FULL) XX(QUIT) \
+#define ACTIONS(XX) XX(NONE) XX(CHOOSE) XX(CHOOSE_FULL) XX(HELP) XX(QUIT) \
XX(UP) XX(DOWN) XX(TOP) XX(BOTTOM) XX(PAGE_PREVIOUS) XX(PAGE_NEXT) \
XX(SCROLL_UP) XX(SCROLL_DOWN) XX(GO_START) XX(GO_HOME) \
XX(SEARCH) XX(RENAME) XX(RENAME_PREFILL) \
@@ -312,7 +336,7 @@ static const char *g_action_names[] = {ACTIONS(XX)};
static map<wint_t, action> g_normal_actions = {
{ALT | '\r', ACTION_CHOOSE_FULL}, {ALT | KEY (ENTER), ACTION_CHOOSE_FULL},
- {'\r', ACTION_CHOOSE}, {KEY (ENTER), ACTION_CHOOSE},
+ {'\r', ACTION_CHOOSE}, {KEY (ENTER), ACTION_CHOOSE}, {'h', ACTION_HELP},
// M-o ought to be the same shortcut the navigator is launched with
{ALT | 'o', ACTION_QUIT}, {'q', ACTION_QUIT},
{'k', ACTION_UP}, {CTRL 'p', ACTION_UP}, {KEY (UP), ACTION_UP},
@@ -386,7 +410,9 @@ static struct {
map<string, chtype> ls_exts; ///< LS_COLORS file extensions
bool ls_symlink_as_target; ///< ln=target in dircolors
- map<string, wint_t, stringcaseless> key_names;
+ map<string, wint_t, stringcaseless> name_to_key;
+ map<wint_t, string> key_to_name;
+ string action_names[ACTION_COUNT]; ///< Stylized action names
// Refreshed by reload():
@@ -469,7 +495,7 @@ fun make_entry (const struct dirent *f) -> entry {
entry e;
e.filename = f->d_name;
e.info.st_mode = DTTOIF (f->d_type);
- auto& info = e.info;
+ auto &info = e.info;
// TODO: benchmark just readdir() vs. lstat(), also on dead mounts;
// it might make sense to stat asynchronously in threads
@@ -622,6 +648,71 @@ fun reload () {
(IN_ALL_EVENTS | IN_ONLYDIR | IN_EXCL_UNLINK) & ~(IN_ACCESS | IN_OPEN));
}
+// TODO: we should be able to signal failures to the user
+fun run_pager (FILE *contents) {
+ // We don't really need to set O_CLOEXEC, so we're not going to
+ rewind (contents);
+ endwin ();
+
+ switch (pid_t child = fork ()) {
+ int status;
+ case -1:
+ break;
+ case 0:
+ // Put the child in a new foreground process group...
+ setpgid (0, 0);
+ tcsetpgrp (STDOUT_FILENO, getpgid (0));
+ dup2 (fileno (contents), STDIN_FILENO);
+
+ // Behaviour copies man-db's man(1), similar to POSIX man(1)
+ for (auto pager : {(const char *) getenv ("PAGER"), "pager", "cat"})
+ if (pager) execl ("/bin/sh", "/bin/sh", "-c", pager, NULL);
+ _exit (EXIT_FAILURE);
+ default:
+ // ...and make sure of it in the parent as well
+ (void) setpgid (child, child);
+ waitpid (child, &status, 0);
+ tcsetpgrp (STDOUT_FILENO, getpgid (0));
+ }
+
+ refresh ();
+ update ();
+}
+
+fun encode_key (wint_t key) -> string {
+ string encoded;
+ if (key & ALT)
+ encoded.append ("M-");
+ wchar_t bare = key & ~ALT;
+ if (g.key_to_name.count (bare))
+ encoded.append (capitalize (g.key_to_name.at (bare)));
+ else if (bare < 32)
+ encoded.append ("C-").append ({char (tolower (bare + 64))});
+ else
+ encoded.append (to_mb ({bare}));
+ return encoded;
+}
+
+fun show_help () {
+ FILE *contents = tmpfile ();
+ if (!contents)
+ return;
+
+ for (const auto &kv : g_binding_contexts) {
+ fprintf (contents, "%s\n",
+ underline (capitalize (kv.first + " key bindings")).c_str ());
+ for (const auto &kv : *kv.second) {
+ auto key = encode_key (kv.first);
+ key.append (max (0, 10 - compute_width (to_wide (key))), ' ');
+ fprintf (contents, "%s %s\n",
+ key.c_str (), g.action_names[kv.second].c_str ());
+ }
+ fprintf (contents, "\n");
+ }
+ run_pager (contents);
+ fclose (contents);
+}
+
fun search (const wstring &needle) {
int best = g.cursor, best_n = 0;
for (int i = 0; i < int (g.entries.size ()); i++) {
@@ -702,6 +793,9 @@ fun handle (wint_t c) -> bool {
if (choose (current))
break;
return false;
+ case ACTION_HELP:
+ show_help ();
+ return true;
case ACTION_QUIT:
return false;
@@ -920,8 +1014,8 @@ fun parse_key (const string &key_name) -> wint_t {
}
c |= CTRL *p;
p += 1;
- } else if (g.key_names.count (p)) {
- return c | g.key_names.at (p);
+ } else if (g.name_to_key.count (p)) {
+ return c | g.name_to_key.at (p);
} else {
wchar_t w; mbstate_t mb {};
auto len = strlen (p) + 1, res = mbrtowc (&w, p, len, &mb);
@@ -943,8 +1037,13 @@ fun parse_key (const string &key_name) -> wint_t {
return c;
}
+fun learn_named_key (const string &name, wint_t key) {
+ g.name_to_key[g.key_to_name[key] = name] = key;
+}
+
fun load_bindings () {
- g.key_names["space"] = ' ';
+ learn_named_key ("space", ' ');
+ learn_named_key ("escape", 0x1b);
for (int kc = KEY_MIN; kc < KEY_MAX; kc++) {
const char *name = keyname (kc);
if (!name)
@@ -956,7 +1055,7 @@ fun load_bindings () {
if (*name != '(' && *name != ')')
filtered += *name;
}
- g.key_names[filtered] = kc;
+ learn_named_key (filtered, SYM | kc);
}
auto config = xdg_config_find ("/" PROJECT_NAME "/bindings");
@@ -970,6 +1069,7 @@ fun load_bindings () {
string name;
for (; *p; p++)
name += *p == '_' ? '-' : *p + 'a' - 'A';
+ g.action_names[a] = name;
actions[name] = action (a++);
}
@@ -1016,6 +1116,9 @@ int main (int argc, char *argv[]) {
auto output_fd = dup (STDOUT_FILENO);
dup2 (STDIN_FILENO, STDOUT_FILENO);
+ // So that the neither us nor our children stop on tcsetpgrp()
+ signal (SIGTTOU, SIG_IGN);
+
if ((g.inotify_fd = inotify_init1 (IN_NONBLOCK)) < 0) {
cerr << "cannot initialize inotify" << endl;
return 1;