keep the last five versions of saved.cfg and init.cfg

Renames the existing saved.cfg to saved-old-1.cfg (and an existing -1 to
-2, and so on) before the new saved.cfg is written.

This should help in cases where players mess up their config, because the
config is deleted with a five-game-starts delay.

source/src/command.cpp

@@ -1430,6 +1430,7 @@ COMMANDF(rnd, "i", (int *a) { intret(*a>0 ? rnd(*a) : 0); });
 #ifndef STANDALONE
 void writecfg()
 {
+    filerotate("config/saved", "cfg", CONFIGROTATEMAX); // keep five old config sets
     stream *f = openfile(path("config/saved.cfg", true), "w");
     if(!f) return;
     f->printf("// automatically written on exit, DO NOT MODIFY\n// delete this file to have defaults.cfg overwrite these settings\n// modify settings in game, or put settings in autoexec.cfg to override anything\n\n");

source/src/cube.h

@@ -66,6 +66,7 @@ extern int verbose;
 #define AC_MASTER_HTTP 1 // default
 #define AC_MASTER_RAW 0
 #define MAXCL 16
+#define CONFIGROTATEMAX 5               // keep 5 old versions of saved.cfg and init.cfg around
 
 #include "protos.h"                     // external function decls
 

source/src/main.cpp

@@ -123,6 +123,7 @@ VARF(fullscreen, 0, 1, 1, setfullscreen(fullscreen!=0));
 void writeinitcfg()
 {
     if(!restoredinits) return;
+    filerotate("config/init", "cfg", CONFIGROTATEMAX); // keep five old init config sets
     stream *f = openfile(path("config/init.cfg", true), "w");
     if(!f) return;
     f->printf("// automatically written on exit, DO NOT MODIFY\n// modify settings in game\n");
@@ -992,22 +993,13 @@ int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int sw)
 
 void initclientlog()  // rotate old logfiles and create new one
 {
-    const int MAXROT = 5;    // keep five old logfiles
-    string fname1, fname2 = "";
-    const char *basename = findfile("clientlog", "w");
-    for(int i = MAXROT; i >= 0; i--)
-    {
-        formatstring(fname1)(i > 0 ? "%s-old-%d.txt" : "%s.txt", basename, i);
-        if(fname2[0]) rename(fname1, fname2);
-        else remove(fname1);
-        copystring(fname2, fname1);
-    }
+    filerotate("clientlog", "txt", 5); // keep five old logfiles
     clientlogfile = openfile("clientlog.txt", "w");
     if(clientlogfile)
     {
         if(bootclientlog && bootclientlog->length()) clientlogfile->write(bootclientlog->getbuf(), bootclientlog->length());
     }
-    else conoutf("could not create logfile \"%s\"", fname2);
+    else conoutf("could not create logfile \"%s\"", findfile("clientlog.txt", "w"));
     DELETEP(bootclientlog);
 }
 

source/src/stream.cpp

@@ -787,3 +787,19 @@ char *loadfile(const char *fn, int *size, const char *mode)
     return buf;
 }
 
+void filerotate(const char *basename, const char *ext, int keepold, const char *oldformat)  // rotate old logfiles
+{
+    char fname1[MAXSTRLEN * 2], fname2[MAXSTRLEN] = "";
+    copystring(fname1, findfile(basename, "w"));
+    int mid = strlen(fname1);
+    if(!oldformat) oldformat = "-old-%d";
+    for(; keepold >= 0; keepold--)
+    {
+        formatstring(fname1 + mid)(keepold ? oldformat : "", keepold);
+        concatformatstring(fname1 + mid, ".%s", ext);
+        if(fname2[0]) rename(fname1, fname2);
+        else remove(fname1);
+        copystring(fname2, fname1);
+    }
+}
+

source/src/tools.h

@@ -945,6 +945,7 @@ extern stream *openfile(const char *filename, const char *mode);
 extern stream *opentempfile(const char *filename, const char *mode);
 extern stream *opengzfile(const char *filename, const char *mode, stream *file = NULL, int level = Z_BEST_COMPRESSION);
 extern char *loadfile(const char *fn, int *size, const char *mode = NULL);
+extern void filerotate(const char *basename, const char *ext, int keepold, const char *oldformat = NULL);
 extern bool listdir(const char *dir, const char *ext, vector<char *> &files);
 extern int listfiles(const char *dir, const char *ext, vector<char *> &files);
 extern int listzipfiles(const char *dir, const char *ext, vector<char *> &files);