Adapt help to terminal size

If the error stream is a terminal, and we can retrieve the terminal
size, wrap the lines at terminal boundaries.

app/meson.build

@@ -29,6 +29,7 @@ src = [
     'src/util/process.c',
     'src/util/strbuf.c',
     'src/util/str_util.c',
+    'src/util/term.c',
     'src/util/thread.c',
     'src/util/tick.c',
 ]
@@ -189,6 +190,7 @@ if get_option('buildtype') == 'debug'
             'src/options.c',
             'src/util/strbuf.c',
             'src/util/str_util.c',
+            'src/util/term.c',
         ]],
         ['test_clock', [
             'tests/test_clock.c',

app/src/cli.c

@@ -4,12 +4,14 @@
 #include <getopt.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 #include "options.h"
 #include "util/log.h"
 #include "util/strbuf.h"
 #include "util/str_util.h"
+#include "util/term.h"
 
 #define STR_IMPL_(x) #x
 #define STR(x) STR_IMPL_(x)
@@ -312,7 +314,7 @@ static const struct sc_option options[] = {
                 "\"lsuper\" and \"rsuper\".\n"
                 "A shortcut can consist in several keys, separated by '+'. "
                 "Several shortcuts can be specified, separated by ','.\n"
-                "For example, to use either LCtrl+LAlt or LSuper for scrcpy\n"
+                "For example, to use either LCtrl+LAlt or LSuper for scrcpy "
                 "shortcuts, pass \"lctrl+lalt,lsuper\".\n"
                 "Default is \"lalt,lsuper\" (left-Alt or left-Super).",
     },
@@ -680,7 +682,7 @@ error:
 
 static void
 print_option_usage(const struct sc_option *opt, unsigned cols) {
-    assert(cols > 20); // We need some space
+    assert(cols > 8); // wrap_lines() requires indent < columns
 
     if (!opt->text) {
         // Option not documented in help (for example because it is deprecated)
@@ -716,7 +718,7 @@ print_shortcuts_intro(unsigned cols) {
 
 static void
 print_shortcut(const struct sc_shortcut *shortcut, unsigned cols) {
-    assert(cols > 20); // We need some space
+    assert(cols > 8); // wrap_lines() requires indent < columns
     assert(shortcut->shortcuts[0]); // At least one shortcut
     assert(shortcut->text);
 
@@ -740,17 +742,30 @@ print_shortcut(const struct sc_shortcut *shortcut, unsigned cols) {
 
 void
 scrcpy_print_usage(const char *arg0) {
+#define SC_TERM_COLS_DEFAULT 80
+    unsigned cols;
+
+    if (!isatty(STDERR_FILENO)) {
+        // Not a tty, use a default value
+        cols = SC_TERM_COLS_DEFAULT;
+    } else {
+        bool ok = sc_term_get_size(NULL, &cols);
+        if (!ok) {
+            cols = SC_TERM_COLS_DEFAULT; // default value
+        }
+    }
+
     fprintf(stderr, "Usage: %s [options]\n\n"
                     "Options:\n", arg0);
     for (size_t i = 0; i < ARRAY_LEN(options); ++i) {
-        print_option_usage(&options[i], 80);
+        print_option_usage(&options[i], cols);
     }
 
     // Print shortcuts section
     fprintf(stderr, "\nShortcuts:\n\n");
-    print_shortcuts_intro(80);
+    print_shortcuts_intro(cols);
     for (size_t i = 0; i < ARRAY_LEN(shortcuts); ++i) {
-        print_shortcut(&shortcuts[i], 80);
+        print_shortcut(&shortcuts[i], cols);
     }
 }
 

app/src/util/str_util.c

@@ -213,6 +213,8 @@ utf8_from_wide_char(const wchar_t *ws) {
 #endif
 
 char *wrap_lines(const char *input, unsigned columns, unsigned indent) {
+    assert(indent < columns);
+
     struct sc_strbuf buf;
 
     // The output string should not be a lot longer than the input string (just
@@ -224,8 +226,6 @@ char *wrap_lines(const char *input, unsigned columns, unsigned indent) {
         return false;
     }
 
-    assert(indent < columns);
-
 #define APPEND(S,N) if (!sc_strbuf_append(&buf, S, N)) goto error
 #define APPEND_CHAR(C) if (!sc_strbuf_append_char(&buf, C)) goto error
 #define APPEND_N(C,N) if (!sc_strbuf_append_n(&buf, C, N)) goto error
@@ -241,7 +241,12 @@ char *wrap_lines(const char *input, unsigned columns, unsigned indent) {
     size_t col = indent;
     while (*input) {
         size_t sep_idx = strcspn(input, "\n ");
-        bool wrap = col + sep_idx > columns;
+        size_t new_col = col + sep_idx;
+        if (pending == ' ') {
+            // The pending space counts
+            ++new_col;
+        }
+        bool wrap = new_col > columns;
 
         char sep = input[sep_idx];
         if (sep == ' ')

app/src/util/term.c

@@ -0,0 +1,51 @@
+#include "term.h"
+
+#include <assert.h>
+
+#ifdef _WIN32
+# include <windows.h>
+#else
+# include <unistd.h>
+# include <sys/ioctl.h>
+#endif
+
+bool
+sc_term_get_size(unsigned *rows, unsigned *cols) {
+#ifdef _WIN32
+    CONSOLE_SCREEN_BUFFER_INFO csbi;
+
+    bool ok =
+        GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi);
+    if (!ok) {
+        return false;
+    }
+
+    if (rows) {
+        assert(csbi.srWindow.Bottom >= csbi.srWindow.Top);
+        *rows = csbi.srWindow.Bottom - csbi.srWindow.Top + 1;
+    }
+
+    if (cols) {
+        assert(csbi.srWindow.Right >= csbi.srWindow.Left);
+        *cols = csbi.srWindow.Right - csbi.srWindow.Left + 1;
+    }
+
+    return true;
+#else
+    struct winsize ws;
+    int r = ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws);
+    if (r == -1) {
+        return false;
+    }
+
+    if (rows) {
+        *rows = ws.ws_row;
+    }
+
+    if (cols) {
+        *cols = ws.ws_col;
+    }
+
+    return true;
+#endif
+}

app/src/util/term.h

@@ -0,0 +1,11 @@
+#ifndef SC_TERM_H
+#define SC_TERM_H
+
+#include "common.h"
+
+#include <stdbool.h>
+
+bool
+sc_term_get_size(unsigned *rows, unsigned *cols);
+
+#endif

app/tests/test_strutil.c

@@ -301,7 +301,7 @@ static void test_strlist_contains(void) {
 
 static void test_wrap_lines(void) {
     const char *s = "This is a text to test line wrapping. The lines must be "
-                    "wrapped either at a space or a line break.\n"
+                    "wrapped at a space or a line break.\n"
                     "\n"
                     "This rectangle must remains a rectangle because it is "
                     "drawn in lines having lengths lower than the specified "
@@ -315,9 +315,8 @@ static void test_wrap_lines(void) {
     const char *expected = "    This is a text to\n"
                            "    test line wrapping.\n"
                            "    The lines must be\n"
-                           "    wrapped either at a\n"
-                           "    space or a line\n"
-                           "    break.\n"
+                           "    wrapped at a space\n"
+                           "    or a line break.\n"
                            "    \n"
                            "    This rectangle must\n"
                            "    remains a rectangle\n"