From 4319228f3dcf3a5f941140482c30cca227c6ed0b Mon Sep 17 00:00:00 2001
From: Ron Yorston <rmy@pobox.com>
Date: Wed, 5 Aug 2020 15:33:12 +0100
Subject: win32: move code to fork (de)compressor to a function

Use a new common function, mingw_fork_compressor(), to implement
fork_transformer() in open_transformer.c and vfork_compressor()
in tar.c.

Saves 160 bytes.
---
 archival/libarchive/open_transformer.c | 16 +---------------
 archival/tar.c                         | 28 +++++-----------------------
 include/mingw.h                        |  1 +
 win32/popen.c                          | 22 ++++++++++++++++++++++
 4 files changed, 29 insertions(+), 38 deletions(-)

diff --git a/archival/libarchive/open_transformer.c b/archival/libarchive/open_transformer.c
index 1ac72af79..3d202ad26 100644
--- a/archival/libarchive/open_transformer.c
+++ b/archival/libarchive/open_transformer.c
@@ -154,21 +154,7 @@ void FAST_FUNC fork_transformer(int fd, const char *transform_prog)
 #else /* ENABLE_PLATFORM_MINGW */
 void FAST_FUNC fork_transformer(int fd, const char *transform_prog)
 {
-	char *cmd;
-	int fd1;
-
-	if (find_applet_by_name(transform_prog) >= 0) {
-		cmd = xasprintf("%s --busybox %s -cf -", bb_busybox_exec_path,
-						transform_prog);
-	}
-	else {
-		cmd = xasprintf("%s -cf -", transform_prog);
-	}
-	if ( (fd1=mingw_popen_fd(cmd, "r", fd, NULL)) == -1 ) {
-		bb_perror_msg_and_die("can't execute '%s'", transform_prog);
-	}
-	free(cmd);
-	xmove_fd(fd1, fd);
+	mingw_fork_compressor(fd, transform_prog, "r");
 }
 #endif
 
diff --git a/archival/tar.c b/archival/tar.c
index c57bff779..c7642a50e 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -601,8 +601,7 @@ static int FAST_FUNC writeFileToTarball(const char *fileName, struct stat *statb
 	return TRUE;
 }
 
-#if SEAMLESS_COMPRESSION
-#if !ENABLE_PLATFORM_MINGW32
+# if SEAMLESS_COMPRESSION && !ENABLE_PLATFORM_MINGW32
 /* Don't inline: vfork scares gcc and pessimizes code */
 static void NOINLINE vfork_compressor(int tar_fd, const char *gzip)
 {
@@ -677,28 +676,11 @@ static void NOINLINE vfork_compressor(int tar_fd, const char *gzip)
 		bb_perror_msg_and_die("can't execute '%s'", gzip);
 	}
 }
-#else
-static pid_t vfork_compressor(int tar_fd, const char *gzip)
-{
-	char *cmd;
-	int fd1;
-	pid_t pid;
+# endif /* SEAMLESS_COMPRESSION */
 
-	if (find_applet_by_name(gzip) >= 0) {
-		cmd = xasprintf("%s --busybox %s -cf -", bb_busybox_exec_path, gzip);
-	}
-	else {
-		cmd = xasprintf("%s -cf -", gzip);
-	}
-	if ( (fd1=mingw_popen_fd(cmd, "w", tar_fd, &pid)) == -1 ) {
-		bb_perror_msg_and_die("can't execute '%s'", gzip);
-	}
-	free(cmd);
-	xmove_fd(fd1, tar_fd);
-	return pid;
-}
-#endif /* ENABLE_PLATFORM_MINGW32 */
-#endif /* SEAMLESS_COMPRESSION */
+# if ENABLE_PLATFORM_MINGW32
+#  define vfork_compressor(f, g) mingw_fork_compressor((f), (g), "w")
+# endif
 
 
 # if !SEAMLESS_COMPRESSION
diff --git a/include/mingw.h b/include/mingw.h
index a67b161c7..16f0396db 100644
--- a/include/mingw.h
+++ b/include/mingw.h
@@ -133,6 +133,7 @@ int mingw_rename(const char*, const char*);
 FILE *mingw_popen(const char *cmd, const char *mode);
 int mingw_popen_fd(const char *cmd, const char *mode, int fd0, pid_t *pid);
 int mingw_pclose(FILE *fd);
+pid_t mingw_fork_compressor(int fd, const char *compressor, const char *mode);
 #undef popen
 #undef pclose
 #define popen mingw_popen
diff --git a/win32/popen.c b/win32/popen.c
index 0da5cde23..8810b8de0 100644
--- a/win32/popen.c
+++ b/win32/popen.c
@@ -306,3 +306,25 @@ int mingw_pclose(FILE *fp)
 
 	return (ret == WAIT_OBJECT_0) ? 0 : -1;
 }
+
+/* Used with mode "w" and a compressor when creating a compressed tar
+ * file; with mode "r" and a decompressor in open_transformer. */
+pid_t mingw_fork_compressor(int fd, const char *compressor, const char *mode)
+{
+	char *cmd;
+	int fd1;
+	pid_t pid;
+
+	if (find_applet_by_name(compressor) >= 0)
+		cmd = xasprintf("%s --busybox %s -cf -", bb_busybox_exec_path,
+					compressor);
+	else
+		cmd = xasprintf("%s -cf -", compressor);
+
+	if ((fd1 = mingw_popen_fd(cmd, mode, fd, &pid)) == -1)
+		bb_perror_msg_and_die("can't execute '%s'", compressor);
+
+	free(cmd);
+	xmove_fd(fd1, fd);
+	return pid;
+}
-- 
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