util, treewide: improve string handling (#33)

* treewide: rename str -> strbuf

This makes the type name more in line with what it actually is (a
mutable buffer holding a string) and is in preparation for adding a new
str type which instead acts similar to Rust's str or C++'s
std::string_view in an effort to move away from null terminated strings.

* util: make strbuf a struct

Using an SDS-style string was interesting but I don't think the benefits
are worth the complexity. It also prevents _Generic from disambiguating
between strbuf and C strings.

* util: add str

This is intended to serve a similar purpose to Rust's str or C++'s
std::string_view.

* test: add tests for str, strbuf

* util: add str_clone_cstr, str_from

* env_reexec: use str for environment manipulation

* config: use str for action parsing

* util: add strbuf_clone_cstr

* server: use strbuf for X11 window title

* util: add ww_strdup

ww_strdup wraps strdup with a NULL check to avoid having to spam
check_alloc everywhere.

* treewide: use ww_strdup

* config, subproc, wrap: use strs for subprocesses

This removes the 63 argument limit (not that anyone was realistically
limited by it.)

* util: remove 0 capacity restriction on strbuf

Author: tesselslate

.clang-format-include

@@ -1,2 +1,3 @@
 include/**.h
 waywall/**.c
+test/**.c

doc/02_waywall_exec.md

@@ -1,9 +1,9 @@
 # exec
 
-This function asynchronously executes the given command as a subprocess. No
-sophisticated argument processing is performed; quoting arguments or performing
-shell substitutions will require you to run a shell script. A maximum of 63
-space-delimited arguments can be provided in the command string.
+This function asynchronously executes the given command as a subprocess.
+Arguments are split by spaces and no further processing is performed; quoting
+arguments or performing shell substitutions will require you to run a shell
+script.
 
 If the spawned subprocess does not exit before waywall, it will be killed with
 `SIGKILL` when waywall closes.

include/instance.h

@@ -34,5 +34,5 @@ struct instance {
 
 struct instance *instance_create(struct server_view *view, struct inotify *inotify);
 void instance_destroy(struct instance *instance);
-str instance_get_state_path(struct instance *instance);
+strbuf instance_get_state_path(struct instance *instance);
 void instance_state_update(struct instance *instance);

include/reload.h

@@ -15,7 +15,7 @@ struct reload {
     reload_func_t func;
     void *data;
 
-    str config_path;
+    strbuf config_path;
     int config_dir_wd;
     struct list_int config_wd;
 

include/subproc.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "util/list.h"
+#include "util/str.h"
 #include <sys/types.h>
 
 LIST_DEFINE(struct subproc_entry, list_subproc_entry);
@@ -18,4 +19,4 @@ struct subproc_entry {
 
 struct subproc *subproc_create(struct server *server);
 void subproc_destroy(struct subproc *subproc);
-void subproc_exec(struct subproc *subproc, char *cmd[static 64]);
+void subproc_exec(struct subproc *subproc, struct strs cmd);

include/util/alloc.h

@@ -3,6 +3,7 @@
 #include "util/prelude.h"
 #include <stddef.h>
 #include <stdlib.h>
+#include <string.h>
 
 #define check_alloc(data)                                                                          \
     do {                                                                                           \
@@ -11,6 +12,15 @@
         }                                                                                          \
     } while (0)
 
+static inline char *
+ww_strdup(const char *str) {
+    ww_assert(str);
+
+    char *dup = strdup(str);
+    check_alloc(dup);
+    return dup;
+}
+
 static inline void *
 zalloc(size_t nmemb, size_t size) {
     void *data = calloc(nmemb, size);

include/util/str.h

@@ -1,8 +1,48 @@
 #pragma once
 
-typedef char *str;
+#include <sys/types.h>
 
-void str_append(str *dst, const char *src);
-void str_clear(str str);
-void str_free(str str);
-str str_new();
+#define str_lit(lit) ((str){sizeof(lit) - 1, lit})
+
+typedef struct {
+    ssize_t len;
+    const char *data;
+} str;
+
+typedef struct {
+    ssize_t len, cap;
+    char *data;
+} strbuf;
+
+struct strs {
+    ssize_t len;
+    str *data;
+};
+
+#define strbuf_append(dst, src)                                                                    \
+    _Generic((src),                                                                                \
+        int: strbuf_append_char,                                                                   \
+        strbuf: strbuf_append_buf,                                                                 \
+        str: strbuf_append_str,                                                                    \
+        default: strbuf_append_cstr)(dst, src)
+
+void strbuf_append_char(strbuf *dst, char src);
+void strbuf_append_cstr(strbuf *dst, const char *src);
+void strbuf_append_buf(strbuf *dst, strbuf src);
+void strbuf_append_str(strbuf *dst, str src);
+void strbuf_clear(strbuf *buf);
+char *strbuf_clone_cstr(strbuf buf);
+void strbuf_free(strbuf *buf);
+strbuf strbuf_new();
+str strbuf_view(strbuf buf);
+
+strbuf str_clone(str s);
+char *str_clone_cstr(str s);
+bool str_eq(str a, str b);
+str str_from(const char *cstr);
+ssize_t str_index(str s, char needle, ssize_t start);
+str str_slice(str s, ssize_t start, ssize_t end);
+struct strs str_split(str s, char sep);
+
+void strs_free(struct strs strs);
+ssize_t strs_index(struct strs strs, str s, ssize_t start);

include/wrap.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "util/box.h"
+#include "util/str.h"
 #include <stdint.h>
 #include <wayland-server-core.h>
 
@@ -55,7 +56,7 @@ struct wrap *wrap_create(struct server *server, struct inotify *inotify, struct
 void wrap_destroy(struct wrap *wrap);
 int wrap_set_config(struct wrap *wrap, struct config *cfg);
 
-void wrap_lua_exec(struct wrap *wrap, char *cmd[static 64]);
+void wrap_lua_exec(struct wrap *wrap, struct strs cmd);
 void wrap_lua_press_key(struct wrap *wrap, uint32_t keycode);
 int wrap_lua_set_res(struct wrap *wrap, int32_t width, int32_t height);
 void wrap_lua_show_floating(struct wrap *wrap, bool show);

meson.build

@@ -75,3 +75,4 @@ waywall_deps = [
 
 subdir('protocol')
 subdir('waywall')
+subdir('test')

test/meson.build

@@ -0,0 +1,17 @@
+waywall_tests = {
+  'str': ['util/prelude.c', 'util/str.c']
+}
+
+foreach name, extra_src : waywall_tests
+  fixed_extra_src = []
+  foreach _extra_src : extra_src
+    fixed_extra_src += meson.global_source_root() + '/waywall/' + _extra_src
+  endforeach
+
+  test(name, executable('test_' + name,
+    files(name + '.c'),
+    files(fixed_extra_src),
+
+    include_directories: includes,
+  ))
+endforeach