libsystem: Add MCSFileGetType().

peter-b · peter-b · commit 0acae79ab87b · 2015-08-13T11:27:51.000+01:00
Basic ability to distinguish between files and directories, given a
path.
diff --git a/libfoundation/include/system-file.h b/libfoundation/include/system-file.h
@@ -112,6 +112,13 @@ bool __MCSFileCreateStream (MCStringRef p_native_path, intenum_t p_mode, MCStrea
  * Filesystem operations
  * ================================================================ */
 
+enum MCSFileType
+{
+	kMCSFileTypeRegular = (1 << 0),
+	kMCSFileTypeDirectory = (1 << 1),
+	kMCSFileTypeSymbolicLink = (1 << 5),
+};
+
 /* Delete the file at path. */
 MC_DLLEXPORT bool MCSFileDelete (MCStringRef p_path);
 
@@ -126,12 +133,17 @@ MC_DLLEXPORT bool MCSFileDeleteDirectory (MCStringRef p_path);
  * returned list never includes "." and "..". */
 MC_DLLEXPORT bool MCSFileGetDirectoryEntries (MCStringRef p_path, MCProperListRef & r_entries);
 
+/* Get the type of the file located at p_path.  If p_follow_links is
+ * true, dereferences symbolic links in p_path. */
+MC_DLLEXPORT bool MCSFileGetType (MCStringRef p_path, bool p_follow_links, MCSFileType & r_type);
+
 #ifdef __MCS_INTERNAL_API__
 
 bool __MCSFileDelete (MCStringRef p_native_path);
 bool __MCSFileCreateDirectory (MCStringRef p_native_path);
 bool __MCSFileDeleteDirectory (MCStringRef p_native_path);
 bool __MCSFileGetDirectoryEntries (MCStringRef p_native_path, MCProperListRef & r_entries);
+bool __MCSFileGetType (MCStringRef p_native_path, bool p_follow_links, MCSFileType & r_type);
 
 #endif
 
diff --git a/libfoundation/src/system-file-posix.cpp b/libfoundation/src/system-file-posix.cpp
@@ -700,3 +700,43 @@ __MCSFileGetDirectoryEntries (MCStringRef p_native_path,
 	free (t_raw_entries);
 	return false;
 }
+
+bool
+__MCSFileGetType (MCStringRef p_native_path,
+                  bool p_follow_links,
+                  MCSFileType & r_type)
+{
+	/* Get a system path */
+	MCAutoStringRefAsSysString t_path_sys;
+	if (!t_path_sys.Lock (p_native_path))
+		return false;
+
+	struct stat t_stat_buf;
+	int t_stat_result;
+
+	if (p_follow_links)
+	{
+		t_stat_result = stat (*t_path_sys, &t_stat_buf);
+	}
+	else
+	{
+		t_stat_result = lstat (*t_path_sys, &t_stat_buf);
+	}
+
+	if (0 != t_stat_result)
+	{
+		return __MCSFileThrowIOErrorWithErrno (p_native_path, MCSTR("Failed to stat %{path}: %{description}"), errno);
+	}
+
+	switch (t_stat_buf.st_mode & S_IFMT)
+	{
+	case S_IFREG: r_type = kMCSFileTypeRegular; break;
+	case S_IFDIR: r_type = kMCSFileTypeDirectory; break;
+	case S_IFLNK: r_type = kMCSFileTypeSymbolicLink; break;
+
+	default:
+		return __MCSFileThrowIOErrorWithErrno (p_native_path, MCSTR("Unsupported file type for %{path}"), EIO);
+	}
+
+	return true;
+}
diff --git a/libfoundation/src/system-file-w32.cpp b/libfoundation/src/system-file-w32.cpp
@@ -757,3 +757,38 @@ __MCSFileGetDirectoryEntries (MCStringRef p_native_path,
 	FindClose (t_find_handle);
 	return false;
 }
+
+bool
+__MCSFileGetType (MCStringRef p_native_path,
+                  bool p_follow_links,
+                  MCSFileType & r_type)
+{
+	/* Get a system path */
+	MCAutoStringRefAsWString t_path_w32;
+	if (!t_path_w32.Lock (p_native_path))
+		return false;
+
+	DWORD t_attributes = GetFileAttributesW(*t_path_w32);
+
+	if (INVALID_FILE_ATTRIBUTES == t_attributes)
+	{
+		return __MCSFileThrowIOErrorWithErrorCode (p_native_path, MCSTR("Failed to get attributes from file '%{path}': %{description}"), p_error_code);
+	}
+
+	/* Symbolic links are indicated by the reparse point flag.  But the other
+	 * relevant attributes are still present. */
+	if ((t_attributes & FILE_ATTRIBUTE_REPARSE_POINT) && !p_follow_links)
+	{
+		r_type = kMCSFileTypeSymbolicLink;
+	}
+	else if (t_attributes & FILE_ATTRIBUTE_DIRECTORY)
+	{
+		r_type = kMCSFileTypeDirectory;
+	}
+	else
+	{
+		r_type = kMCSFileTypeRegular;
+	}
+
+	return true;
+}
diff --git a/libfoundation/src/system-file.cpp b/libfoundation/src/system-file.cpp
@@ -197,6 +197,15 @@ MCSFileGetDirectoryEntries (MCStringRef p_path,
 	                        NULL);
 }
 
+MC_DLLEXPORT_DEF bool
+MCSFileGetType (MCStringRef p_path,
+                bool p_follow_links,
+                MCSFileType & r_type)
+{
+	MCS_FILE_CONVERT_PATH(p_path, t_native_path);
+	return __MCSFileGetType(t_native_path, p_follow_links, r_type);
+}
+
 /* ================================================================
  * Initialization
  * ================================================================ */
