add directory class which can be used to enumerate files. #29

CMakeLists.txt

@@ -4,4 +4,4 @@ if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR CMAKE_CXX_COMPILER_ID MATCHES "GNU"
   # Enable C++11 mode on GCC / Clang
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 endif()
-add_executable(path_demo path_demo.cpp filesystem/path.h filesystem/resolver.h)
+add_executable(path_demo path_demo.cpp filesystem/path.h filesystem/resolver.h filesystem/directory.h)

filesystem/directory.h

@@ -0,0 +1,152 @@
+
+/*
+ * reference https://docs.microsoft.com/zh-cn/cpp/c-runtime-library/reference/findfirst-functions?f1url=https%3A%2F%2Fmsdn.microsoft.com%2Fquery%2Fdev15.query%3FappId%3DDev15IDEF1%26l%3DZH-CN%26k%3Dk(CORECRT_IO%2F_findfirst);k(_findfirst);k(DevLang-C%2B%2B);k(TargetOS-Windows)%26rd%3Dtrue&view=vs-2019
+ * reference http://www.man7.org/linux/man-pages/man3/opendir.3.html
+ * 
+ * Copyright (c) 2019 tangm421 <[email protected]>
+ *
+ * All rights reserved. Use of this source code is governed by a
+ * BSD-style license that can be found in the LICENSE file.
+ */
+
+#pragma once
+
+#include "path.h"
+
+#if defined(_WIN32)
+#include <io.h>
+#else
+#include <sys/types.h>   
+#include <dirent.h>
+#endif
+
+NAMESPACE_BEGIN(filesystem)
+
+class directory : public path
+{
+public:
+    directory(const path& dir) : path(dir), m_dir(dir) {}
+
+    class iterator
+    {
+    public:
+        iterator() /* default ctor indicates the end iterator */
+#if defined(_WIN32)
+            : m_handle(-1) {}
+#else
+            : m_handle(NULL), m_data(NULL) {}
+#endif
+
+        iterator(const directory& dir) {
+            m_dir = dir;
+#if defined(_WIN32)
+            std::string search_path(dir.make_absolute().str() + "/*.*");
+            m_handle = _findfirst(search_path.c_str(), &m_data);
+            if (is_valid_handler())
+            {
+                m_result = m_dir / m_data.name;
+            }
+            else /* an error occurs or  reaching the end */
+            {
+                /* do nothing */
+            }
+#else
+            m_handle = opendir(dir.make_absolute().str().c_str());
+            ++*this; /* here we do find the first directory entry like the begin iterator does */
+#endif
+        }
+        ~iterator() {
+            if (is_valid_handler())
+            {
+#if defined(_WIN32)
+                _findclose(m_handle);
+                m_handle = -1;
+#else
+                closedir(m_handle);
+                m_handle = NULL;
+                m_data = NULL;
+#endif
+            }
+        }
+
+        iterator& operator++() {
+            if (is_valid_handler())
+            {
+#if defined(_WIN32)
+                if (_findnext(m_handle, &m_data))
+                {
+                    if (ENOENT == errno) /* reaching the end */
+                    {
+                        m_result = path();
+                    }
+                    else /* an error occurs */
+                    {
+                        /* do nothing because the next call of this function will not do anything */
+                    }
+                }
+                else
+                {
+                    m_result = m_dir / m_data.name;
+                }
+#else
+                errno = 0;
+                m_data = readdir(m_handle);
+                if (0 != errno) /* an error occurs */
+                {
+                    /* do nothing because the next call of this function will not do anything */
+                }
+                if (!m_data) /* reaching the end */
+                {
+                    m_result = path();
+                }
+                else
+                {
+                    m_result = m_dir / m_data->d_name;
+                }
+#endif
+            }
+            return *this;
+        }
+        bool operator!=(const iterator& rhs) const {
+            return !(*this == rhs);
+        }
+        bool operator==(const iterator& rhs) const {
+            return **this == *rhs;
+        }
+        const path& operator*() const {
+            return m_result;
+        }
+        const path* operator->() const {
+            return &m_result;
+        }
+
+    protected:
+        bool is_valid_handler() const {
+#if defined(_WIN32)
+            return -1 != m_handle;
+#else
+            return NULL != m_handle;
+#endif
+        }
+
+    private:
+        path m_dir;
+        path m_result;
+#if defined(_WIN32)
+        intptr_t m_handle;
+        _finddata_t m_data;
+#else
+        DIR* m_handle;
+        struct dirent* m_data;
+#endif
+    };
+
+    iterator begin() const { return iterator(*this); }
+    iterator end() const { static iterator static_end; return static_end; };
+
+private:
+    path m_dir;
+};
+
+
+NAMESPACE_END(filesystem)

path_demo.cpp

@@ -1,6 +1,7 @@
 #include <iostream>
 #include "filesystem/path.h"
 #include "filesystem/resolver.h"
+#include "filesystem/directory.h"
 
 using namespace std;
 using namespace filesystem;
@@ -44,5 +45,35 @@ int main(int argc, char **argv) {
 
     cout << "resolve(filesystem/path.h) = " << resolver().resolve("filesystem/path.h") << endl;
     cout << "resolve(nonexistant) = " << resolver().resolve("nonexistant") << endl;
+
+    //////////////////////////////////////////////////////////////////////////
+    directory dir1(".");
+    directory dir2("..");
+    if (dir1 == dir2)
+    {
+        cout << "dir1:" << dir1 << " equal to dir2:" << dir2 << endl;
+    }
+    else
+    {
+        cout << "dir1:" << dir1 << " not equal to dir2:" << dir2 << endl;
+    }
+
+    directory::iterator begin(dir1);
+    directory::iterator end;
+    for (; begin != end; ++begin)
+    {
+        cout << *begin << endl;
+    }
+
+    directory::iterator b = dir2.begin();
+    directory::iterator e = dir2.end();
+    for (; b != e; ++b)
+    {
+        if (b->is_file())
+        {
+            cout << *b << endl;
+        }
+    }
+
     return 0;
 }