Add directory interface.

1 files changed, 192 insertions, 0 deletions

diff --git a/source/fud_directory.cpp b/source/fud_directory.cpp
new file mode 100644
index 0000000..39f2e10
--- /dev/null
+++ b/source/fud_directory.cpp
@@ -0,0 +1,192 @@
+/*
+ * libfud
+ * Copyright 2024 Dominick Allen
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fud_directory.hpp"
+
+#include <cerrno>
+#include <fcntl.h>
+#include <sys/stat.h>
+
+namespace fud {
+
+Directory::Directory(String name) : m_name{name}
+{
+    if (!m_name.valid()) {
+        return;
+    }
+
+    if (!m_name.utf8Valid()) {
+        m_status = FudStatus::Utf8Invalid;
+        return;
+    }
+
+    m_directory = opendir(m_name.c_str());
+    if (m_directory == nullptr) {
+        m_status = FudStatus::Failure;
+        m_errorCode = errno;
+        return;
+    }
+
+    m_dirFd = dirfd(m_directory);
+    if (m_dirFd == -1) {
+        m_status = FudStatus::Failure;
+        m_errorCode = errno;
+        closedir(m_directory);
+        m_directory = nullptr;
+        return;
+    }
+
+    m_errorCode = 0;
+    m_status = FudStatus::Success;
+}
+
+Directory::Directory(Directory&& rhs) :
+    m_name{std::move(rhs.m_name)}, m_directory{rhs.m_directory}, m_dirFd{rhs.m_dirFd}
+{
+    rhs.m_directory = nullptr;
+    rhs.m_dirFd = -1;
+}
+
+Directory& Directory::operator=(Directory&& rhs)
+{
+    m_name = std::move(rhs.m_name);
+    m_directory = rhs.m_directory;
+    m_dirFd = rhs.m_dirFd;
+
+    rhs.m_directory = nullptr;
+    rhs.m_dirFd = -1;
+
+    return *this;
+}
+
+Directory::~Directory()
+{
+    if (m_directory != nullptr) {
+        closedir(m_directory);
+        m_directory = nullptr;
+    }
+}
+
+Result<std::optional<DirectoryEntry>, FudStatus> Directory::getNextEntry()
+{
+    using RetType = Result<std::optional<DirectoryEntry>, FudStatus>;
+
+    if (m_directory == nullptr || m_dirFd == -1) {
+        m_status = FudStatus::ObjectInvalid;
+        return RetType::error(m_status);
+    }
+
+    errno = 0;
+    auto* dirEntry = readdir(m_directory);
+    if (dirEntry == nullptr) {
+        if (errno != 0) {
+            m_errorCode = errno;
+            m_status = FudStatus::Failure;
+            return RetType::error(m_status);
+        } else {
+            return RetType::okay(std::nullopt);
+        }
+    }
+
+    const char* entryName = dirEntry->d_name;
+    if (entryName == nullptr) {
+        m_errorCode = -1;
+        m_status = FudStatus::NullPointer;
+        return RetType::error(m_status);
+    }
+
+    m_errorCode = 0;
+
+    using Stat = struct stat;
+    Stat statBuffer{};
+    auto flags = 0;
+    auto status = fstatat(m_dirFd, entryName, &statBuffer, flags);
+    if (status == -1) {
+        m_errorCode = errno;
+        m_status = FudStatus::Failure;
+        return RetType::error(m_status);
+    }
+
+    DirectoryEntryType entryType;
+    switch (statBuffer.st_mode & S_IFMT) {
+    case S_IFBLK:
+        entryType = DirectoryEntryType::Block;
+        break;
+    case S_IFCHR:
+        entryType = DirectoryEntryType::Character;
+        break;
+    case S_IFDIR:
+        entryType = DirectoryEntryType::Directory;
+        break;
+    case S_IFIFO:
+        entryType = DirectoryEntryType::NamedPipe;
+        break;
+    case S_IFLNK:
+        entryType = DirectoryEntryType::SymbolicLink;
+        break;
+    case S_IFREG:
+        entryType = DirectoryEntryType::RegularFile;
+        break;
+    case S_IFSOCK:
+        entryType = DirectoryEntryType::UnixSocket;
+        break;
+    default:
+        entryType = DirectoryEntryType::Unknown;
+        break;
+    }
+
+    static_assert(std::is_same_v<decltype(statBuffer.st_size), long>);
+    static_assert(sizeof(decltype(statBuffer.st_size)) <= sizeof(size_t));
+
+    size_t size{0};
+    if (statBuffer.st_size < 0) {
+        size = SIZE_MAX;
+    } else {
+        size = static_cast<size_t>(statBuffer.st_size);
+    }
+
+    static_assert(std::is_same_v<decltype(statBuffer.st_nlink), unsigned long>);
+    static_assert(sizeof(decltype(statBuffer.st_nlink)) <= sizeof(size_t));
+
+    DirectoryEntry entry{
+        String{dirEntry->d_name},
+        size,
+        static_cast<size_t>(statBuffer.st_nlink),
+        statBuffer.st_mtime,
+        entryType};
+
+    if (!entry.name.valid()) {
+        m_status = FudStatus::StringInvalid;
+        return RetType::error(m_status);
+    }
+
+    m_status = FudStatus::Success;
+    return RetType::okay(std::move(entry));
+}
+
+FudStatus Directory::reset()
+{
+    if (m_directory != nullptr) {
+        rewinddir(m_directory);
+    } else {
+        m_status = FudStatus::ObjectInvalid;
+        return m_status;
+    }
+    return FudStatus::NotImplemented;
+}
+
+} // namespace fud