3 files changed, 127 insertions, 73 deletions

diff --git a/src/fileio.cpp b/src/fileio.cpp
index 8201b7c0f..9e141c6e5 100644
--- a/src/fileio.cpp
+++ b/src/fileio.cpp
@@ -956,3 +956,98 @@ void *ReadFileToMem(const char *filename, size_t *lenp, size_t maxsize)
 	*lenp = len;
 	return mem;
 }
+
+
+/**
+ * Scan a single directory (and recursively it's children) and add
+ * any graphics sets that are found.
+ * @param extension       the extension of files to search for.
+ * @param path            full path we're currently at
+ * @param basepath_length from where in the path are we 'based' on the search path
+ */
+static uint ScanPath(FileScanner *fs, const char *extension, const char *path, size_t basepath_length)
+{
+	extern bool FiosIsValidFile(const char *path, const struct dirent *ent, struct stat *sb);
+
+	uint num = 0;
+	struct stat sb;
+	struct dirent *dirent;
+	DIR *dir;
+
+	if (path == NULL || (dir = ttd_opendir(path)) == NULL) return 0;
+
+	while ((dirent = readdir(dir)) != NULL) {
+		const char *d_name = FS2OTTD(dirent->d_name);
+		char filename[MAX_PATH];
+
+		if (!FiosIsValidFile(path, dirent, &sb)) continue;
+
+		snprintf(filename, lengthof(filename), "%s%s", path, d_name);
+
+		if (sb.st_mode & S_IFDIR) {
+			/* Directory */
+			if (strcmp(d_name, ".") == 0 || strcmp(d_name, "..") == 0) continue;
+			AppendPathSeparator(filename, lengthof(filename));
+			num += ScanPath(fs, extension, filename, basepath_length);
+		} else if (sb.st_mode & S_IFREG) {
+			/* File */
+			char *ext = strrchr(filename, '.');
+
+			/* If no extension or extension isn't .grf, skip the file */
+			if (ext == NULL) continue;
+			if (strcasecmp(ext, extension) != 0) continue;
+
+			if (fs->AddFile(filename, basepath_length)) num++;
+		}
+	}
+
+	closedir(dir);
+
+	return num;
+}
+
+/**
+ * Scan the given tar and add graphics sets when it finds one.
+ * @param extension the extension of files to search for.
+ * @param tar       the tar to search in.
+ */
+static uint ScanTar(FileScanner *fs, const char *extension, TarFileList::iterator tar)
+{
+	uint num = 0;
+	const char *filename = (*tar).first.c_str();
+	const char *ext = strrchr(filename, '.');
+
+	/* If no extension or extension isn't .grf, skip the file */
+	if (ext == NULL) return false;
+	if (strcasecmp(ext, extension) != 0) return false;
+
+	if (fs->AddFile(filename, 0)) num++;
+
+	return num;
+}
+
+/**
+ * Scan for files with the given extention in the given search path.
+ * @param extension the extension of files to search for.
+ * @param sp        the sub directory to search in.
+ * @param tars      whether to search in the tars too.
+ * @return the number of found files, i.e. the number of times that
+ *         AddFile returned true.
+ */
+uint FileScanner::Scan(const char *extension, Subdirectory sd, bool tars)
+{
+	Searchpath sp;
+	char path[MAX_PATH];
+	TarFileList::iterator tar;
+	uint num = 0;
+
+	FOR_ALL_SEARCHPATHS(sp) {
+		FioAppendDirectory(path, MAX_PATH, sp, sd);
+		num += ScanPath(this, extension, path, strlen(path));
+	}
+	FOR_ALL_TARS(tar) {
+		num += ScanTar(this, extension, tar);
+	}
+
+	return num;
+}
diff --git a/src/fileio.h b/src/fileio.h
index 6d4aed2b4..7c8a80221 100644
--- a/src/fileio.h
+++ b/src/fileio.h
@@ -96,4 +96,20 @@ bool FileExists(const char *filename);
 
 extern char *_personal_dir; ///< custom directory for personal settings, saves, newgrf, etc.
 
+/** Helper for scanning for files with a given name */
+class FileScanner
+{
+public:
+	uint Scan(const char *extension, Subdirectory sd, bool tars = true);
+
+	/**
+	 * Add a file with the given filename.
+	 * @param filename        the full path to the file to read
+	 * @param basepath_length amount of characters to chop of before to get a
+	 *                        filename relative to the search path.
+	 * @return true if the file is added.
+	 */
+	virtual bool AddFile(const char *filename, size_t basepath_length) = 0;
+};
+
 #endif /* FILEIO_H */
diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
index a8aeb2f63..6faeb8d77 100644
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -15,10 +15,8 @@
 #include "gamelog.h"
 #include "network/network_type.h"
 
-#include "tar_type.h"
 #include "fileio.h"
 #include "fios.h"
-#include <sys/stat.h>
 
 
 GRFConfig *_all_grfs;
@@ -267,10 +265,23 @@ compatible_grf:
 	return res;
 }
 
-static bool ScanPathAddGrf(const char *filename)
+/** Helper for scanning for files with GRF as extension */
+class GRFFileScanner : FileScanner {
+public:
+	/* virtual */ bool AddFile(const char *filename, size_t basepath_length);
+
+	/** Do the scan for GRFs. */
+	static uint DoScan()
+	{
+		GRFFileScanner fs;
+		return fs.Scan(".grf", DATA_DIR);
+	}
+};
+
+bool GRFFileScanner::AddFile(const char *filename, size_t basepath_length)
 {
 	GRFConfig *c = CallocT<GRFConfig>(1);
-	c->filename = strdup(filename);
+	c->filename = strdup(filename + basepath_length);
 
 	bool added = true;
 	if (FillGRFDetails(c, false)) {
@@ -313,63 +324,6 @@ static bool ScanPathAddGrf(const char *filename)
 	return added;
 }
 
-/* Scan a path for NewGRFs */
-static uint ScanPath(const char *path, size_t basepath_length)
-{
-	extern bool FiosIsValidFile(const char *path, const struct dirent *ent, struct stat *sb);
-
-	uint num = 0;
-	struct stat sb;
-	struct dirent *dirent;
-	DIR *dir;
-
-	if (path == NULL || (dir = ttd_opendir(path)) == NULL) return 0;
-
-	while ((dirent = readdir(dir)) != NULL) {
-		const char *d_name = FS2OTTD(dirent->d_name);
-		char filename[MAX_PATH];
-
-		if (!FiosIsValidFile(path, dirent, &sb)) continue;
-
-		snprintf(filename, lengthof(filename), "%s%s", path, d_name);
-
-		if (sb.st_mode & S_IFDIR) {
-			/* Directory */
-			if (strcmp(d_name, ".") == 0 || strcmp(d_name, "..") == 0) continue;
-			AppendPathSeparator(filename, lengthof(filename));
-			num += ScanPath(filename, basepath_length);
-		} else if (sb.st_mode & S_IFREG) {
-			/* File */
-			char *ext = strrchr(filename, '.');
-
-			/* If no extension or extension isn't .grf, skip the file */
-			if (ext == NULL) continue;
-			if (strcasecmp(ext, ".grf") != 0) continue;
-
-			if (ScanPathAddGrf(filename + basepath_length)) num++;
-		}
-	}
-
-	closedir(dir);
-
-	return num;
-}
-
-static uint ScanTar(TarFileList::iterator tar)
-{
-	uint num = 0;
-	const char *filename = (*tar).first.c_str();
-	const char *ext = strrchr(filename, '.');
-
-	/* If no extension or extension isn't .grf, skip the file */
-	if (ext == NULL) return false;
-	if (strcasecmp(ext, ".grf") != 0) return false;
-
-	if (ScanPathAddGrf(filename)) num++;
-
-	return num;
-}
-
 /**
  * Simple sorter for GRFS
  * @param p1 the first GRFConfig *
@@ -388,21 +342,10 @@ static int CDECL GRFSorter(const void *p1, const void *p2)
 /* Scan for all NewGRFs */
 void ScanNewGRFFiles()
 {
-	Searchpath sp;
-	char path[MAX_PATH];
-	TarFileList::iterator tar;
-	uint num = 0;
-
 	ClearGRFConfigList(&_all_grfs);
 
 	DEBUG(grf, 1, "Scanning for NewGRFs");
-	FOR_ALL_SEARCHPATHS(sp) {
-		FioAppendDirectory(path, MAX_PATH, sp, DATA_DIR);
-		num += ScanPath(path, strlen(path));
-	}
-	FOR_ALL_TARS(tar) {
-		num += ScanTar(tar);
-	}
+	uint num = GRFFileScanner::DoScan();
 
 	DEBUG(grf, 1, "Scan complete, found %d files", num);
 	if (num == 0 || _all_grfs == NULL) return;