From a9cb4f8245c0143ddd963b9eb0cf7226b4369746 Mon Sep 17 00:00:00 2001
From: ISSOtm <eldredhabert0@gmail.com>
Date: Sat, 9 Nov 2019 01:09:54 +0100
Subject: [PATCH 1/2] Make RGBASM overwrite output files atomically Fixes
 rednex/#446. I am not sure this is the best (in cases where the target
 directory is not writable but the target file is), but maybe this can be
 toggled via a flag, for example.

---
 src/asm/output.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/asm/output.c b/src/asm/output.c
index 1a019682..1c83f8e9 100644
--- a/src/asm/output.c
+++ b/src/asm/output.c
@@ -16,6 +16,8 @@
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
+#include <libgen.h>
 
 #include "asm/asm.h"
 #include "asm/charmap.h"
@@ -532,13 +534,25 @@ static void checksectionoverflow(uint32_t delta_size)
  */
 void out_WriteObject(void)
 {
+	/* Write to a temporary file in the target's folder */
+	char *objectNameCopy = strdup(tzObjectname);
+	char const *dirPath = dirname(objectNameCopy);
+	char tmpFileName[strlen(dirPath) + 1 + 16 + 1];
+
+	sprintf(tmpFileName, "%s/rgbasm_tmpXXXXXX", dirPath);
+	free(objectNameCopy);
+	int fd = mkstemp(tmpFileName);
+
 	FILE *f;
 	struct PatchSymbol *pSym;
 	struct Section *pSect;
 
+	if (fd == -1)
+		err(1, "Couldn't create temporary file");
+
 	addexports();
 
-	f = fopen(tzObjectname, "wb");
+	f = fdopen(fd, "wb");
 	if (f == NULL)
 		fatalerror("Couldn't write file '%s'\n", tzObjectname);
 
@@ -560,6 +574,11 @@ void out_WriteObject(void)
 	}
 
 	fclose(f);
+	close(fd);
+
+	if (rename(tmpFileName, tzObjectname) != 0)
+		err(1, "Couldn't create object file (temp file kept as %s)",
+		    tmpFileName);
 }
 
 /*

From 2e8094b71237c139d08ab373513112b258c143e4 Mon Sep 17 00:00:00 2001
From: ISSOtm <eldredhabert0@gmail.com>
Date: Tue, 28 Jan 2020 11:07:46 +0100
Subject: [PATCH 2/2] Allow RGBASM to overwrite object files on Windows

---
 src/asm/output.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/asm/output.c b/src/asm/output.c
index 1c83f8e9..dce91101 100644
--- a/src/asm/output.c
+++ b/src/asm/output.c
@@ -19,6 +19,21 @@
 #include <unistd.h>
 #include <libgen.h>
 
+#ifdef _WIN32
+#include <windows.h>
+#include <winbase.h>
+/*
+ * The semantics of `rename` on Windows differ from POSIX in that it errors out
+ * when the target file exists, instead of overwriting it.
+ * Thus, shim `rename` with similar semantics (note that the return value of
+ * `MoveFileExA` is inverted, and it uses `GetLastError` instead of `errno`)
+ */
+#define rename(oldname, newname) \
+	MoveFileExA(oldname, newname, MOVEFILE_WRITE_THROUGH | \
+				      MOVEFILE_REPLACE_EXISTING) \
+	? 0 : (errno = GetLastError(), -1)
+#endif
+
 #include "asm/asm.h"
 #include "asm/charmap.h"
 #include "asm/fstack.h"