From 38c350fad589148ceb8f02a1df815a9555ef0f2e Mon Sep 17 00:00:00 2001
From: frosch <frosch@openttd.org>
Date: Sun, 17 Oct 2010 12:14:49 +0000
Subject: [PATCH] (svn r20960) -Add: Allow setting 'minimal compatible version'
 via Action14. (planetmaker)  Note: Setting 'VRSN' also sets 'MINV' resulting
 in the Grf being only compatible to the same version. Set 'MINV' after 'VRSN'
 if your Grf is compatible to older versions.

---
 src/lang/english.txt  |  1 +
 src/newgrf.cpp        | 23 ++++++++++++++++++++++-
 src/newgrf_config.cpp |  1 +
 src/newgrf_gui.cpp    |  4 ++++
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/lang/english.txt b/src/lang/english.txt
index 1c853a6956..2dd0d8d760 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -2400,6 +2400,7 @@ STR_NEWGRF_SETTINGS_FIND_MISSING_CONTENT_TOOLTIP                :{BLACK}Check wh
 STR_NEWGRF_SETTINGS_FILENAME                                    :{BLACK}Filename: {SILVER}{RAW_STRING}
 STR_NEWGRF_SETTINGS_GRF_ID                                      :{BLACK}GRF ID: {SILVER}{RAW_STRING}
 STR_NEWGRF_SETTINGS_VERSION                                     :{BLACK}Version: {SILVER}{NUM}
+STR_NEWGRF_SETTINGS_MIN_VERSION                                 :{BLACK}Min. compatible version: {SILVER}{NUM}
 STR_NEWGRF_SETTINGS_MD5SUM                                      :{BLACK}MD5sum: {SILVER}{RAW_STRING}
 STR_NEWGRF_SETTINGS_PALETTE                                     :{BLACK}Palette: {SILVER}{RAW_STRING}
 STR_NEWGRF_SETTINGS_PARAMETER                                   :{BLACK}Parameters: {SILVER}{STRING1}
diff --git a/src/newgrf.cpp b/src/newgrf.cpp
index a63696ba16..44ec6e3db6 100644
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -6326,11 +6326,31 @@ static bool ChangeGRFVersion(size_t len, ByteReader *buf)
 		grfmsg(2, "StaticGRFInfo: expected 4 bytes for 'INFO'->'VRSN' but got " PRINTF_SIZE ", ignoring this field", len);
 		buf->Skip(len);
 	} else {
-		_cur_grfconfig->version = buf->ReadDWord();
+		/* Set min_loadable_version as well (default to minimal compatibility) */
+		_cur_grfconfig->version = _cur_grfconfig->min_loadable_version = buf->ReadDWord();
 	}
 	return true;
 }
 
+/** Callback function for 'INFO'->'MINV' to the minimum compatible version of the NewGRF. */
+static bool ChangeGRFMinVersion(size_t len, ByteReader *buf)
+{
+	if (len != 4) {
+		grfmsg(2, "StaticGRFInfo: expected 4 bytes for 'INFO'->'MINV' but got " PRINTF_SIZE ", ignoring this field", len);
+		buf->Skip(len);
+	} else {
+		_cur_grfconfig->min_loadable_version = buf->ReadDWord();
+		if (_cur_grfconfig->version == 0) {
+			grfmsg(2, "StaticGRFInfo: 'MINV' defined before 'VRSN' or 'VRSN' set to 0, ignoring this field");
+			_cur_grfconfig->min_loadable_version = 0;
+		}
+		if (_cur_grfconfig->version < _cur_grfconfig->min_loadable_version) {
+			grfmsg(2, "StaticGRFInfo: 'MINV' defined as %d, limiting it to 'VRSN'", _cur_grfconfig->min_loadable_version);
+			_cur_grfconfig->min_loadable_version = _cur_grfconfig->version;
+		}
+	}
+	return true;
+}
 
 static GRFParameterInfo *_cur_parameter; ///< The parameter which info is currently changed by the newgrf.
 
@@ -6583,6 +6603,7 @@ AllowedSubtags _tags_info[] = {
 	AllowedSubtags('NPAR', ChangeGRFNumUsedParams),
 	AllowedSubtags('PALS', ChangeGRFPalette),
 	AllowedSubtags('VRSN', ChangeGRFVersion),
+	AllowedSubtags('MINV', ChangeGRFMinVersion),
 	AllowedSubtags('PARA', HandleParameterInfo),
 	AllowedSubtags()
 };
diff --git a/src/newgrf_config.cpp b/src/newgrf_config.cpp
index b951ebfe2a..763941e20a 100644
--- a/src/newgrf_config.cpp
+++ b/src/newgrf_config.cpp
@@ -40,6 +40,7 @@ GRFConfig::GRFConfig(const GRFConfig &config) :
 	ZeroedMemoryAllocator(),
 	ident(config.ident),
 	version(config.version),
+	min_loadable_version(config.min_loadable_version),
 	flags(config.flags & ~GCF_COPY),
 	status(config.status),
 	grf_bugs(config.grf_bugs),
diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
index 5169feb575..d97a852ea0 100644
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -85,6 +85,10 @@ static void ShowNewGRFInfo(const GRFConfig *c, uint x, uint y, uint right, uint
 		SetDParam(0, c->version);
 		y = DrawStringMultiLine(x, right, y, bottom, STR_NEWGRF_SETTINGS_VERSION);
 	}
+	if (_settings_client.gui.newgrf_show_old_versions && c->min_loadable_version != 0) {
+		SetDParam(0, c->min_loadable_version);
+		y = DrawStringMultiLine(x, right, y, bottom, STR_NEWGRF_SETTINGS_MIN_VERSION);
+	}
 
 	/* Prepare and draw MD5 sum */
 	md5sumToString(buff, lastof(buff), c->ident.md5sum);