add a range to iterate a directory

build.cc

@@ -14,6 +14,7 @@
 #include "ostd/range.hh"
 #include "ostd/format.hh"
 #include "ostd/string.hh"
+#include "ostd/path.hh"
 #include "ostd/filesystem.hh"
 #include "ostd/thread_pool.hh"
 #include "ostd/channel.hh"
@@ -24,6 +25,7 @@ namespace fs = ostd::filesystem;
 /* ugly, but do not explicitly compile */
 #include "src/io.cc"
 #include "src/process.cc"
+#include "srC/path.cc"
 #include "src/filesystem.cc"
 #include "src/thread_pool.cc"
 #include "src/channel.cc"

ostd/path.hh

@@ -366,6 +366,10 @@ struct path {
         p_path = ".";
     }
 
+    bool empty() const {
+        return (p_path == ".");
+    }
+
     void swap(path &other) noexcept {
         p_path.swap(other.p_path);
         std::swap(p_fmt, other.p_fmt);
@@ -689,6 +693,84 @@ namespace fs {
  * @{
  */
 
+struct directory_entry {
+    directory_entry() {}
+    directory_entry(ostd::path const &p): p_path(p) {}
+
+    ostd::path const &path() const noexcept {
+        return p_path;
+    }
+
+    operator ostd::path const &() const noexcept {
+        return p_path;
+    }
+
+    void clear() {
+        p_path.clear();
+    }
+
+    void assign(ostd::path const &p) {
+        p_path = p;
+    }
+
+    void assign(ostd::path &&p) {
+        p_path = std::move(p);
+    }
+
+private:
+    ostd::path p_path{};
+};
+
+struct directory_range: input_range<directory_range> {
+    using range_category = input_range_tag;
+    using value_type = directory_entry;
+    using reference = directory_entry const &;
+    using size_type = std::size_t;
+
+    directory_range() = delete;
+    directory_range(path const &p) {
+        open(p);
+    }
+
+    directory_range(directory_range const &r) noexcept:
+        p_current(r.p_current), p_dir(r.p_dir),
+        p_handle(r.p_handle), p_owned(false)
+    {}
+
+    ~directory_range() {
+        close();
+    }
+
+    directory_range &operator=(directory_range const &r) noexcept {
+        close();
+        p_handle = r.p_handle;
+        p_owned = false;
+        return *this;
+    }
+
+    bool empty() const noexcept {
+        return p_current.path().empty();
+    }
+
+    void pop_front() {
+        read_next();
+    }
+
+    reference front() const noexcept {
+        return p_current;
+    }
+
+private:
+    void open(path const &p);
+    void close() noexcept;
+    void read_next();
+
+    directory_entry p_current{};
+    path p_dir{};
+    void *p_handle = nullptr;
+    bool p_owned = false;
+};
+
 OSTD_EXPORT path cwd();
 OSTD_EXPORT path home();
 

src/path.cc

@@ -0,0 +1,14 @@
+/* Decides between POSIX and Windows for path.
+ *
+ * This file is part of libostd. See COPYING.md for futher information.
+ */
+
+#include "ostd/platform.hh"
+
+#if defined(OSTD_PLATFORM_WIN32)
+#  include "src/win32/path.cc"
+#elif defined(OSTD_PLATFORM_POSIX)
+#  include "src/posix/path.cc"
+#else
+#  error "Unsupported platform"
+#endif

src/posix/path.cc

@@ -0,0 +1,59 @@
+/* Path implementation bits.
+ *
+ * This file is part of libostd. See COPYING.md for futher information.
+ */
+
+#include <cstdlib>
+#include <dirent.h>
+
+#include "ostd/path.hh"
+
+namespace ostd {
+namespace fs {
+
+void directory_range::open(path const &p) {
+    DIR *d = opendir(p.string().data());
+    if (!d) {
+        /* FIXME: throw */
+        abort();
+    }
+    p_dir = p;
+    p_handle = d;
+    p_owned = true;
+    read_next();
+}
+
+void directory_range::close() noexcept {
+    if (!p_owned) {
+        return;
+    }
+    closedir(static_cast<DIR *>(p_handle));
+    p_owned = false;
+}
+
+void directory_range::read_next() {
+    struct dirent d;
+    struct dirent *o;
+    DIR *dh = static_cast<DIR *>(p_handle);
+    for (;;) {
+        if (readdir_r(dh, &d, &o)) {
+            /* FIXME: throw */
+            abort();
+        }
+        if (!o) {
+            p_current.clear();
+            return;
+        }
+        string_range nm{static_cast<char const *>(o->d_name)};
+        if ((nm == ".") || (nm == "..")) {
+            continue;
+        }
+        path p{p_dir};
+        p.append(nm);
+        p_current.assign(std::move(p));
+        break;
+    }
+}
+
+} /* namesapce fs */
+} /* namespace ostd */

src/win32/path.cc

@@ -0,0 +1,6 @@
+/* Path implementation bits.
+ *
+ * This file is part of libostd. See COPYING.md for futher information.
+ */
+
+#error "path doesn't work on Windows at this time"