From 36f048c5e488005da0a9dfba6b617c7c9951c7cf Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Tue, 15 Aug 2017 14:04:16 +0200
Subject: sha1dc: build git plumbing code more explicitly

The plumbing code between sha1dc and git is defined in
sha1dc_git.[ch], but these aren't compiled / included directly but
only via the indirect inclusion from sha1dc code.  This is slightly
confusing when you try to trace the build flow.

This patch brings the following changes for simplification:

  - Make sha1dc_git.c stand-alone and build from Makefile

  - sha1dc_git.h is the common header to include further sha1.h
    depending on the build condition

  - Move comments for plumbing codes from the header to definitions

This is also meant as a preliminary work for further plumbing with
external sha1dc shlib.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Makefile b/Makefile
index 461c845..5e7e902 100644
--- a/Makefile
+++ b/Makefile
@@ -1472,6 +1472,8 @@ ifdef APPLE_COMMON_CRYPTO
 	BASIC_CFLAGS += -DSHA1_APPLE
 else
 	DC_SHA1 := YesPlease
+	BASIC_CFLAGS += -DSHA1_DC
+	LIB_OBJS += sha1dc_git.o
 ifdef DC_SHA1_SUBMODULE
 	LIB_OBJS += sha1collisiondetection/lib/sha1.o
 	LIB_OBJS += sha1collisiondetection/lib/ubc_check.o
@@ -1481,12 +1483,9 @@ else
 	LIB_OBJS += sha1dc/ubc_check.o
 endif
 	BASIC_CFLAGS += \
-		-DSHA1_DC \
 		-DSHA1DC_NO_STANDARD_INCLUDES \
 		-DSHA1DC_INIT_SAFE_HASH_DEFAULT=0 \
 		-DSHA1DC_CUSTOM_INCLUDE_SHA1_C="\"cache.h\"" \
-		-DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C="\"sha1dc_git.c\"" \
-		-DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H="\"sha1dc_git.h\"" \
 		-DSHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C="\"git-compat-util.h\""
 endif
 endif
diff --git a/hash.h b/hash.h
index bef3e63..024d0d3 100644
--- a/hash.h
+++ b/hash.h
@@ -8,11 +8,7 @@
 #elif defined(SHA1_OPENSSL)
 #include <openssl/sha.h>
 #elif defined(SHA1_DC)
-#ifdef DC_SHA1_SUBMODULE
-#include "sha1collisiondetection/lib/sha1.h"
-#else
-#include "sha1dc/sha1.h"
-#endif
+#include "sha1dc_git.h"
 #else /* SHA1_BLK */
 #include "block-sha1/sha1.h"
 #endif
diff --git a/sha1dc_git.c b/sha1dc_git.c
index 4d32b4f..7946641 100644
--- a/sha1dc_git.c
+++ b/sha1dc_git.c
@@ -1,8 +1,8 @@
+#include "cache.h"
+
 /*
- * This code is included at the end of sha1dc/sha1.c with the
- * SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C macro.
+ * Same as SHA1DCFinal, but convert collision attack case into a verbose die().
  */
-
 void git_SHA1DCFinal(unsigned char hash[20], SHA1_CTX *ctx)
 {
 	if (!SHA1DCFinal(hash, ctx))
@@ -11,6 +11,9 @@ void git_SHA1DCFinal(unsigned char hash[20], SHA1_CTX *ctx)
 	    sha1_to_hex(hash));
 }
 
+/*
+ * Same as SHA1DCUpdate, but adjust types to match git's usual interface.
+ */
 void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *vdata, unsigned long len)
 {
 	const char *data = vdata;
diff --git a/sha1dc_git.h b/sha1dc_git.h
index a8a5c1d..af3e951 100644
--- a/sha1dc_git.h
+++ b/sha1dc_git.h
@@ -1,16 +1,12 @@
-/*
- * This code is included at the end of sha1dc/sha1.h with the
- * SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H macro.
- */
+/* Plumbing with collition-detecting SHA1 code */
 
-/*
- * Same as SHA1DCFinal, but convert collision attack case into a verbose die().
- */
-void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *);
+#ifdef DC_SHA1_SUBMODULE
+#include "sha1collisiondetection/lib/sha1.h"
+#else
+#include "sha1dc/sha1.h"
+#endif
 
-/*
- * Same as SHA1DCUpdate, but adjust types to match git's usual interface.
- */
+void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *);
 void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len);
 
 #define platform_SHA_CTX SHA1_CTX
-- 
cgit v0.10.2-6-g49f6