du: Port to LibMain

This ports 'du' utility to LibMain. Also moves to use StringView and
StringView literals more instead of raw C strings.

Userland/Utilities/CMakeLists.txt

@@ -85,6 +85,7 @@ target_link_libraries(diff LibDiff LibMain)
 target_link_libraries(dirname LibMain)
 target_link_libraries(disasm LibX86)
 target_link_libraries(dmesg LibMain)
+target_link_libraries(du LibMain)
 target_link_libraries(echo LibMain)
 target_link_libraries(env LibMain)
 target_link_libraries(expr LibRegex LibMain)

Userland/Utilities/du.cpp

@@ -4,8 +4,6 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/Assertions.h>
-#include <AK/ByteBuffer.h>
 #include <AK/LexicalPath.h>
 #include <AK/NumberFormat.h>
 #include <AK/String.h>
@@ -14,8 +12,9 @@
 #include <LibCore/DateTime.h>
 #include <LibCore/DirIterator.h>
 #include <LibCore/File.h>
+#include <LibCore/System.h>
+#include <LibMain/Main.h>
 #include <limits.h>
-#include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
 
@@ -35,27 +34,24 @@ struct DuOption {
     Vector<String> excluded_patterns;
 };
 
-static int parse_args(int argc, char** argv, Vector<String>& files, DuOption& du_option, int& max_depth);
+static ErrorOr<void> parse_args(Main::Arguments arguments, Vector<String>& files, DuOption& du_option, int& max_depth);
-static int print_space_usage(const String& path, const DuOption& du_option, int max_depth);
+static ErrorOr<void> print_space_usage(const String& path, const DuOption& du_option, int max_depth);
 
-int main(int argc, char** argv)
+ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
     Vector<String> files;
     DuOption du_option;
     int max_depth = INT_MAX;
 
-    if (parse_args(argc, argv, files, du_option, max_depth))
+    TRY(parse_args(arguments, files, du_option, max_depth));
-        return 1;
 
-    for (const auto& file : files) {
+    for (const auto& file : files)
-        if (print_space_usage(file, du_option, max_depth))
+        TRY(print_space_usage(file, du_option, max_depth));
-            return 1;
-    }
 
     return 0;
 }
 
-int parse_args(int argc, char** argv, Vector<String>& files, DuOption& du_option, int& max_depth)
+ErrorOr<void> parse_args(Main::Arguments arguments, Vector<String>& files, DuOption& du_option, int& max_depth)
 {
     bool summarize = false;
     const char* pattern = nullptr;
@@ -69,12 +65,12 @@ int parse_args(int argc, char** argv, Vector<String>& files, DuOption& du_option
         "time",
         0,
         "time-type",
-        [&du_option](const char* s) {
+        [&du_option](StringView s) {
-            if (!strcmp(s, "mtime") || !strcmp(s, "modification"))
+            if (s == "mtime"sv || s == "modification"sv)
                 du_option.time_type = DuOption::TimeType::Modification;
-            else if (!strcmp(s, "ctime") || !strcmp(s, "status") || !strcmp(s, "use"))
+            else if (s == "ctime"sv || s == "status"sv || s == "use"sv)
                 du_option.time_type = DuOption::TimeType::Status;
-            else if (!strcmp(s, "atime") || !strcmp(s, "access"))
+            else if (s == "atime"sv || s == "access"sv)
                 du_option.time_type = DuOption::TimeType::Access;
             else
                 return false;
@@ -95,7 +91,7 @@ int parse_args(int argc, char** argv, Vector<String>& files, DuOption& du_option
     args_parser.add_option(pattern, "Exclude files that match pattern", "exclude", 0, "pattern");
     args_parser.add_option(exclude_from, "Exclude files that match any pattern in file", "exclude_from", 'X', "file");
     args_parser.add_positional_argument(files_to_process, "File to process", "file", Core::ArgsParser::Required::No);
-    args_parser.parse(argc, argv);
+    args_parser.parse(arguments);
 
     if (summarize)
         max_depth = 0;
@@ -103,9 +99,7 @@ int parse_args(int argc, char** argv, Vector<String>& files, DuOption& du_option
     if (pattern)
         du_option.excluded_patterns.append(pattern);
     if (exclude_from) {
-        auto file = Core::File::construct(exclude_from);
+        auto file = TRY(Core::File::open(exclude_from, Core::OpenMode::ReadOnly));
-        bool success = file->open(Core::OpenMode::ReadOnly);
-        VERIFY(success);
         const auto buff = file->read_all();
         if (!buff.is_empty()) {
             String patterns = String::copy(buff, Chomp);
@@ -121,30 +115,23 @@ int parse_args(int argc, char** argv, Vector<String>& files, DuOption& du_option
         files.append(".");
     }
 
-    return 0;
+    return {};
 }
 
-int print_space_usage(const String& path, const DuOption& du_option, int max_depth)
+ErrorOr<void> print_space_usage(const String& path, const DuOption& du_option, int max_depth)
 {
-    struct stat path_stat;
+    struct stat path_stat = TRY(Core::System::lstat(path.characters()));
-    if (lstat(path.characters(), &path_stat) < 0) {
-        perror("lstat");
-        return 1;
-    }
-
-    int ret = 0;
-
     if (--max_depth >= 0 && S_ISDIR(path_stat.st_mode)) {
         auto di = Core::DirIterator(path, Core::DirIterator::SkipParentAndBaseDir);
         if (di.has_error()) {
-            warnln("du: cannot read directory '{}': {}", path, di.error_string());
+            outln("du: cannot read directory '{}': {}", path, di.error_string());
-            ret = 1;
+            return Error::from_string_literal("An error occurred. See previous error."sv);
         }
+
         while (di.has_next()) {
             const auto child_path = di.next_full_path();
             if (du_option.all || Core::File::is_directory(child_path)) {
-                if (print_space_usage(child_path, du_option, max_depth))
+                TRY(print_space_usage(child_path, du_option, max_depth));
-                    return 1;
             }
         }
     }
@@ -152,7 +139,7 @@ int print_space_usage(const String& path, const DuOption& du_option, int max_dep
     const auto basename = LexicalPath::basename(path);
     for (const auto& pattern : du_option.excluded_patterns) {
         if (basename.matches(pattern, CaseSensitivity::CaseSensitive))
-            return 0;
+            return {};
     }
 
     off_t size = path_stat.st_size;
@@ -162,7 +149,7 @@ int print_space_usage(const String& path, const DuOption& du_option, int max_dep
     }
 
     if ((du_option.threshold > 0 && size < du_option.threshold) || (du_option.threshold < 0 && size > -du_option.threshold))
-        return 0;
+        return {};
 
     if (du_option.human_readable) {
         out("{}", human_readable_size(size));
@@ -191,5 +178,5 @@ int print_space_usage(const String& path, const DuOption& du_option, int max_dep
         outln("\t{}\t{}", formatted_time, path);
     }
 
-    return ret;
+    return {};
 }