From 98df223c1740f88459b2fec6059027ad185031be Mon Sep 17 00:00:00 2001
From: Nathan Woods <npwoods@mess.org>
Date: Tue, 6 Sep 2016 07:37:31 -0400
Subject: [PATCH] Allows devices to indicate whether image creation should be
 supported at the command line

This addresses MT bug #6372.  The prior issue is that creating serial and/or printer output relied on how image_load() would create images that were not there.  This behavior was not universally desirable (the consensus was that it was wrong for disk images, up in the air for cassettes etc).  This change makes it possible for devices to control this behavior.

Currently I have it associated with image_type(); this might not be the ideal fix.
---
 src/emu/diimage.cpp | 38 ++++++++++++++++++++++++++++++++++++++
 src/emu/diimage.h   |  2 ++
 src/emu/image.cpp   |  4 ++++
 3 files changed, 44 insertions(+)

diff --git a/src/emu/diimage.cpp b/src/emu/diimage.cpp
index c95e9c6a60e..ded57d4dc83 100644
--- a/src/emu/diimage.cpp
+++ b/src/emu/diimage.cpp
@@ -539,6 +539,34 @@ UINT32 device_image_interface::crc()
 	return crc;
 }
 
+
+//-------------------------------------------------
+//  support_command_line_image_creation - do we
+//	want to support image creation from the front
+//	end command line?
+//-------------------------------------------------
+
+bool device_image_interface::support_command_line_image_creation() const
+{
+	bool result;
+	switch (image_type())
+	{
+	case IO_PRINTER:
+	case IO_SERIAL:
+	case IO_PARALLEL:
+		// going by the assumption that these device image types should support this
+		// behavior; ideally we'd get rid of IO_* and just push this to the specific
+		// devices
+		result = true;
+		break;
+	default:
+		result = false;
+		break;
+	}
+	return result;
+}
+
+
 // ****************************************************************************
 // Battery functions
 //
@@ -1158,6 +1186,16 @@ image_init_result device_image_interface::finish_load()
 }
 
 
+//-------------------------------------------------
+//  create - create a image
+//-------------------------------------------------
+
+image_init_result device_image_interface::create(const std::string &path)
+{
+	return create(path, nullptr, nullptr);
+}
+
+
 //-------------------------------------------------
 //  create - create a image
 //-------------------------------------------------
diff --git a/src/emu/diimage.h b/src/emu/diimage.h
index 3ec5f46a52a..f8928012d81 100644
--- a/src/emu/diimage.h
+++ b/src/emu/diimage.h
@@ -158,6 +158,7 @@ public:
 	virtual bool is_creatable() const = 0;
 	virtual bool must_be_loaded() const = 0;
 	virtual bool is_reset_on_load() const = 0;
+	virtual bool support_command_line_image_creation() const;
 	virtual const char *image_interface() const { return nullptr; }
 	virtual const char *file_extensions() const = 0;
 	virtual const option_guide *create_option_guide() const { return nullptr; }
@@ -235,6 +236,7 @@ public:
 	image_init_result finish_load();
 	void unload();
 	image_init_result create(const std::string &path, const image_device_format *create_format, util::option_resolution *create_args);
+	image_init_result create(const std::string &path);
 	bool load_software(software_list_device &swlist, const char *swname, const rom_entry *entry);
 	int reopen_for_write(const std::string &path);
 
diff --git a/src/emu/image.cpp b/src/emu/image.cpp
index 06998ad37e6..8ce958fc79f 100644
--- a/src/emu/image.cpp
+++ b/src/emu/image.cpp
@@ -55,6 +55,10 @@ image_manager::image_manager(running_machine &machine)
 			if (result != image_init_result::PASS)
 				result = image.load(image_name);
 
+			// failing that, try creating it (if appropriate)
+			if (result != image_init_result::PASS && image.support_command_line_image_creation())
+				result = image.create(image_name);
+
 			// did the image load fail?
 			if (result != image_init_result::PASS)
 			{