[9front] [PATCH] diff: retain original file names

[9front] [PATCH] diff: retain original file names

[Ori Bernstein]

When diffing non-regular files, like /dev/null,
pipes, and similar, diff will generate a temp
file to diff against. This is the right thing
to do, but the temp file leaks into the diff.

This patch retains the original file name all
the way through to diff output.
---
diff 4649189126e1ad98f9a07afd078096227668bfd1 23f8872bc10fbe9ffd2b0067db1f91d8eaaabb40
--- a/sys/src/cmd/diff/diff.h	Sun May 22 12:34:33 2022
+++ b/sys/src/cmd/diff/diff.h	Sun May 22 12:41:47 2022
@@ -23,8 +23,8 @@
 void *erealloc(void *, unsigned);
 void diff(char *, char *, int);
 void diffdir(char *, char *, int);
-void diffreg(char *, char *);
-Biobuf *prepare(int, char *);
+void diffreg(char *, char *, char *, char *);
+Biobuf *prepare(int, char *, char *);
 void panic(int, char *, ...);
 void check(Biobuf *, Biobuf *);
 void change(int, int, int, int);
--- a/sys/src/cmd/diff/diffio.c	Sun May 22 12:34:33 2022
+++ b/sys/src/cmd/diff/diffio.c	Sun May 22 12:41:47 2022
@@ -104,7 +104,7 @@
 }
 
 Biobuf *
-prepare(int i, char *arg)
+prepare(int i, char *arg, char *orig)
 {
 	Line *p;
 	int j, h;
@@ -143,11 +143,10 @@
 	file[i] = p;
 	input[i] = bp;			/*fix*/
 	if (i == 0) {			/*fix*/
-		file1 = arg;
+		file1 = orig;
 		firstchange = 0;
-	}
-	else
-		file2 = arg;
+	} else
+		file2 = orig;
 	return bp;
 }
 
--- a/sys/src/cmd/diff/diffreg.c	Sun May 22 12:34:33 2022
+++ b/sys/src/cmd/diff/diffreg.c	Sun May 22 12:41:47 2022
@@ -363,16 +363,16 @@
 }
 
 void
-diffreg(char *f, char *t)
+diffreg(char *f, char *fo, char *t, char *to)
 {
 	Biobuf *b0, *b1;
 	int k;
 
 	binary = 0;
-	b0 = prepare(0, f);
+	b0 = prepare(0, f, fo);
 	if (!b0)
 		return;
-	b1 = prepare(1, t);
+	b1 = prepare(1, t, to);
 	if (!b1) {
 		Bterm(b0);
 		return;
--- a/sys/src/cmd/diff/main.c	Sun May 22 12:34:33 2022
+++ b/sys/src/cmd/diff/main.c	Sun May 22 12:41:47 2022
@@ -149,7 +149,7 @@
 			Bprint(&stdout, "Common subdirectories: %s and %s\n", fp, tp);
 	}
 	else if (REGULAR_FILE(fsb) && REGULAR_FILE(tsb))
-		diffreg(fp, tp);
+		diffreg(fp, f, tp, t);
 	else {
 		if (REGULAR_FILE(fsb)) {
 			if ((p = utfrrune(f, '/')) == 0)
@@ -157,14 +157,14 @@
 			else
 				p++;
 			if (mkpathname(tb, tp, p) == 0)
-				diffreg(fp, tb);
+				diffreg(fp, f, tb, t);
 		} else {
 			if ((p = utfrrune(t, '/')) == 0)
 				p = t;
 			else
 				p++;
 			if (mkpathname(fb, fp, p) == 0)
-				diffreg(fb, tp);
+				diffreg(fb, f, tp, t);
 		}
 	}
 	free(fsb);

Re: [9front] [PATCH] diff: retain original file names

[Jacob Moody]

On 5/22/22 10:41, Ori Bernstein wrote:
> 
> When diffing non-regular files, like /dev/null,
> pipes, and similar, diff will generate a temp
> file to diff against. This is the right thing
> to do, but the temp file leaks into the diff.
> 
> This patch retains the original file name all
> the way through to diff output.

This has been a pet peeve of mine, glad to see
I wasn't the only one. Looks good to me! One
small comment inline that I could take or leave.

> ---
> diff 4649189126e1ad98f9a07afd078096227668bfd1 23f8872bc10fbe9ffd2b0067db1f91d8eaaabb40
> --- a/sys/src/cmd/diff/diff.h	Sun May 22 12:34:33 2022
> +++ b/sys/src/cmd/diff/diff.h	Sun May 22 12:41:47 2022
> @@ -23,8 +23,8 @@
>  void *erealloc(void *, unsigned);
>  void diff(char *, char *, int);
>  void diffdir(char *, char *, int);
> -void diffreg(char *, char *);
> -Biobuf *prepare(int, char *);
> +void diffreg(char *, char *, char *, char *);
> +Biobuf *prepare(int, char *, char *);
>  void panic(int, char *, ...);
>  void check(Biobuf *, Biobuf *);
>  void change(int, int, int, int);
> --- a/sys/src/cmd/diff/diffio.c	Sun May 22 12:34:33 2022
> +++ b/sys/src/cmd/diff/diffio.c	Sun May 22 12:41:47 2022
> @@ -104,7 +104,7 @@
>  }
>  
>  Biobuf *
> -prepare(int i, char *arg)
> +prepare(int i, char *arg, char *orig)
>  {
>  	Line *p;
>  	int j, h;
> @@ -143,11 +143,10 @@
>  	file[i] = p;
>  	input[i] = bp;			/*fix*/
>  	if (i == 0) {			/*fix*/

Is there any context for why these /*fix*/ comments are here? Could
we just delete them?

> -		file1 = arg;
> +		file1 = orig;
>  		firstchange = 0;
> -	}
> -	else
> -		file2 = arg;
> +	} else
> +		file2 = orig;
>  	return bp;
>  }
>  
> --- a/sys/src/cmd/diff/diffreg.c	Sun May 22 12:34:33 2022
> +++ b/sys/src/cmd/diff/diffreg.c	Sun May 22 12:41:47 2022
> @@ -363,16 +363,16 @@
>  }
>  
>  void
> -diffreg(char *f, char *t)
> +diffreg(char *f, char *fo, char *t, char *to)
>  {
>  	Biobuf *b0, *b1;
>  	int k;
>  
>  	binary = 0;
> -	b0 = prepare(0, f);
> +	b0 = prepare(0, f, fo);
>  	if (!b0)
>  		return;
> -	b1 = prepare(1, t);
> +	b1 = prepare(1, t, to);
>  	if (!b1) {
>  		Bterm(b0);
>  		return;
> --- a/sys/src/cmd/diff/main.c	Sun May 22 12:34:33 2022
> +++ b/sys/src/cmd/diff/main.c	Sun May 22 12:41:47 2022
> @@ -149,7 +149,7 @@
>  			Bprint(&stdout, "Common subdirectories: %s and %s\n", fp, tp);
>  	}
>  	else if (REGULAR_FILE(fsb) && REGULAR_FILE(tsb))
> -		diffreg(fp, tp);
> +		diffreg(fp, f, tp, t);
>  	else {
>  		if (REGULAR_FILE(fsb)) {
>  			if ((p = utfrrune(f, '/')) == 0)
> @@ -157,14 +157,14 @@
>  			else
>  				p++;
>  			if (mkpathname(tb, tp, p) == 0)
> -				diffreg(fp, tb);
> +				diffreg(fp, f, tb, t);
>  		} else {
>  			if ((p = utfrrune(t, '/')) == 0)
>  				p = t;
>  			else
>  				p++;
>  			if (mkpathname(fb, fp, p) == 0)
> -				diffreg(fb, tp);
> +				diffreg(fb, f, tp, t);
>  		}
>  	}
>  	free(fsb);

Re: [9front] [PATCH] diff: retain original file names

[ori]

Quoth Jacob Moody <moody@mail.posixcafe.org>:
> On 5/22/22 10:41, Ori Bernstein wrote:
> > 
> > When diffing non-regular files, like /dev/null,
> > pipes, and similar, diff will generate a temp
> > file to diff against. This is the right thing
> > to do, but the temp file leaks into the diff.
> > 
> > This patch retains the original file name all
> > the way through to diff output.
> 
> This has been a pet peeve of mine, glad to see
> I wasn't the only one. Looks good to me! One
> small comment inline that I could take or leave.
> 

pushed, fixed comment in separate commit.

thanks!