userdiff: add a builtin pattern for dts files

The Linux kernel receives many patches to the devicetree files each
release. The hunk header for those patches typically show nothing,
making it difficult to figure out what node is being modified without
applying the patch or opening the file and seeking to the context. Let's
add a builtin 'dts' pattern to git so that users can get better diff
output on dts files when they use the diff=dts driver.

The regex has been constructed based on the spec at devicetree.org[1]
and with some help from Johannes Sixt.

[1] https://github.com/devicetree-org/devicetree-specification/releases/latest

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

14 files changed, 168 insertions, 0 deletions

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index fb1d188d44..c5a528c667 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -810,6 +810,8 @@ patterns are available:
 
 - `css` suitable for cascading style sheets.
 
+- `dts` suitable for devicetree (DTS) files.
+
 - `fortran` suitable for source code in the Fortran language.
 
 - `fountain` suitable for Fountain documents.
diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index 9261d6d3a0..6f5ef0035e 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh
@@ -31,6 +31,7 @@ diffpatterns="
 	cpp
 	csharp
 	css
+	dts
 	fortran
 	fountain
 	golang
diff --git a/t/t4018/dts-labels b/t/t4018/dts-labels
new file mode 100644
index 0000000000..b21ef8737b
--- /dev/null
+++ b/t/t4018/dts-labels
@@ -0,0 +1,9 @@
+/ {
+	label_1: node1@ff00 {
+		label2: RIGHT {
+			vendor,some-property;
+
+			ChangeMe = <0x45-30>;
+		};
+	};
+};
diff --git a/t/t4018/dts-node-unitless b/t/t4018/dts-node-unitless
new file mode 100644
index 0000000000..c5287d9141
--- /dev/null
+++ b/t/t4018/dts-node-unitless
@@ -0,0 +1,8 @@
+/ {
+	label_1: node1 {
+		RIGHT {
+			prop-array = <1>, <4>;
+			ChangeMe = <0xffeedd00>;
+		};
+	};
+};
diff --git a/t/t4018/dts-nodes b/t/t4018/dts-nodes
new file mode 100644
index 0000000000..5a4334bb16
--- /dev/null
+++ b/t/t4018/dts-nodes
@@ -0,0 +1,8 @@
+/ {
+	label_1: node1@ff00 {
+		RIGHT@deadf00,4000 {
+			#size-cells = <1>;
+			ChangeMe = <0xffeedd00>;
+		};
+	};
+};
diff --git a/t/t4018/dts-nodes-comment1 b/t/t4018/dts-nodes-comment1
new file mode 100644
index 0000000000..559dfce9b3
--- /dev/null
+++ b/t/t4018/dts-nodes-comment1
@@ -0,0 +1,8 @@
+/ {
+	label_1: node1@ff00 {
+		RIGHT@deadf00,4000 /* &a comment */ {
+			#size-cells = <1>;
+			ChangeMe = <0xffeedd00>;
+		};
+	};
+};
diff --git a/t/t4018/dts-nodes-comment2 b/t/t4018/dts-nodes-comment2
new file mode 100644
index 0000000000..27e9718b31
--- /dev/null
+++ b/t/t4018/dts-nodes-comment2
@@ -0,0 +1,8 @@
+/ {
+	label_1: node1@ff00 {
+		RIGHT@deadf00,4000 { /* a trailing comment */ 
+			#size-cells = <1>;
+			ChangeMe = <0xffeedd00>;
+		};
+	};
+};
diff --git a/t/t4018/dts-reference b/t/t4018/dts-reference
new file mode 100644
index 0000000000..8f0c87d863
--- /dev/null
+++ b/t/t4018/dts-reference
@@ -0,0 +1,9 @@
+&label_1 {
+	TEST = <455>;
+};
+
+&RIGHT {
+	vendor,some-property;
+
+	ChangeMe = <0x45-30>;
+};
diff --git a/t/t4018/dts-root b/t/t4018/dts-root
new file mode 100644
index 0000000000..2ef9e6ffaa
--- /dev/null
+++ b/t/t4018/dts-root
@@ -0,0 +1,5 @@
+/RIGHT { /* Technically just supposed to be a slash */
+	#size-cells = <1>;
+
+	ChangeMe = <0xffeedd00>;
+};
diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh
index 912df91226..9a93c2a3e0 100755
--- a/t/t4034-diff-words.sh
+++ b/t/t4034-diff-words.sh
@@ -303,6 +303,7 @@ test_language_driver bibtex
 test_language_driver cpp
 test_language_driver csharp
 test_language_driver css
+test_language_driver dts
 test_language_driver fortran
 test_language_driver html
 test_language_driver java
diff --git a/t/t4034/dts/expect b/t/t4034/dts/expect
new file mode 100644
index 0000000000..560fc99184
--- /dev/null
+++ b/t/t4034/dts/expect
@@ -0,0 +1,37 @@
+<BOLD>diff --git a/pre b/post<RESET>
+<BOLD>index b6a9051..7803aee 100644<RESET>
+<BOLD>--- a/pre<RESET>
+<BOLD>+++ b/post<RESET>
+<CYAN>@@ -1,32 +1,32 @@<RESET>
+/ {<RESET>
+	<RED>this_handle<RESET><GREEN>HANDLE_2<RESET>: <RED>node<RESET><GREEN>new-node<RESET>@<RED>f00<RESET><GREEN>eeda<RESET> {
+		compatible = "<RED>mydev<RESET><GREEN>vendor,compat<RESET>";
+		string-prop = <RED>start<RESET><GREEN>end<RESET>: "hello <RED>world!<RESET><GREEN>world?<RESET>" <RED>end<RESET><GREEN>start<RESET>: ;
+		<RED>#size-cells<RESET><GREEN>#address-cells<RESET> = <<RED>0+0<RESET><GREEN>0+40<RESET>>;
+		reg = <<RED>0xf00<RESET><GREEN>0xeeda<RESET>>;
+		prop = <<GREEN>(<RESET>1<GREEN>)<RESET>>;
+		prop = <<GREEN>(<RESET>-1e10<GREEN>)<RESET>>;
+		prop = <(!<RED>3<RESET><GREEN>1<RESET>)>;
+		prop = <(~<RED>3<RESET><GREEN>1<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>*<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>&<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>*<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>/<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>%<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3+4<RESET><GREEN>1+2<RESET>)>;
+		prop = <(<RED>3-4<RESET><GREEN>1-2<RESET>)>;
+		prop = /bits/ <RED>64<RESET><GREEN>32<RESET> <(<RED>3<RESET><GREEN>1<RESET><<<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>>><RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>&<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>^<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>|<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>&&<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>3<RESET><GREEN>1<RESET>||<RED>4<RESET><GREEN>2<RESET>)>;
+		prop = <(<RED>4?5<RESET><GREEN>1?2<RESET>:3)>;
+		list = <&<RED>this_handle<RESET><GREEN>HANDLE_2<RESET>>, <0 0 0 <RED>0<RESET><GREEN>1<RESET>>;
+	};<RESET>
+
+	&<RED>phandle<RESET><GREEN>phandle2<RESET> {
+		<RED>pre-phandle<RESET><GREEN>prop_handle<RESET> = <&<RED>this_handle<RESET><GREEN>HANDLE_2<RESET>>;
+	};<RESET>
+};<RESET>
diff --git a/t/t4034/dts/post b/t/t4034/dts/post
new file mode 100644
index 0000000000..7803aee280
--- /dev/null
+++ b/t/t4034/dts/post
@@ -0,0 +1,32 @@
+/ {
+	HANDLE_2: new-node@eeda {
+		compatible = "vendor,compat";
+		string-prop = end: "hello world?" start: ;
+		#address-cells = <0+40>;
+		reg = <0xeeda>;
+		prop = <(1)>;
+		prop = <(-1e10)>;
+		prop = <(!1)>;
+		prop = <(~1)>;
+		prop = <(1*2)>;
+		prop = <(1&2)>;
+		prop = <(1*2)>;
+		prop = <(1/2)>;
+		prop = <(1%2)>;
+		prop = <(1+2)>;
+		prop = <(1-2)>;
+		prop = /bits/ 32 <(1<<2)>;
+		prop = <(1>>2)>;
+		prop = <(1&2)>;
+		prop = <(1^2)>;
+		prop = <(1|2)>;
+		prop = <(1&&2)>;
+		prop = <(1||2)>;
+		prop = <(1?2:3)>;
+		list = <&HANDLE_2>, <0 0 0 1>;
+	};
+
+	&phandle2 {
+		prop_handle = <&HANDLE_2>;
+	};
+};
diff --git a/t/t4034/dts/pre b/t/t4034/dts/pre
new file mode 100644
index 0000000000..b6a905113c
--- /dev/null
+++ b/t/t4034/dts/pre
@@ -0,0 +1,32 @@
+/ {
+	this_handle: node@f00 {
+		compatible = "mydev";
+		string-prop = start: "hello world!" end: ;
+		#size-cells = <0+0>;
+		reg = <0xf00>;
+		prop = <1>;
+		prop = <-1e10>;
+		prop = <(!3)>;
+		prop = <(~3)>;
+		prop = <(3*4)>;
+		prop = <(3&4)>;
+		prop = <(3*4)>;
+		prop = <(3/4)>;
+		prop = <(3%4)>;
+		prop = <(3+4)>;
+		prop = <(3-4)>;
+		prop = /bits/ 64 <(3<<4)>;
+		prop = <(3>>4)>;
+		prop = <(3&4)>;
+		prop = <(3^4)>;
+		prop = <(3|4)>;
+		prop = <(3&&4)>;
+		prop = <(3||4)>;
+		prop = <(4?5:3)>;
+		list = <&this_handle>, <0 0 0 0>;
+	};
+
+	&phandle {
+		pre-phandle = <&this_handle>;
+	};
+};
diff --git a/userdiff.c b/userdiff.c
index e74a6d4022..86e3244e15 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -23,6 +23,14 @@ IPATTERN("ada",
 	 "[a-zA-Z][a-zA-Z0-9_]*"
 	 "|[-+]?[0-9][0-9#_.aAbBcCdDeEfF]*([eE][+-]?[0-9_]+)?"
 	 "|=>|\\.\\.|\\*\\*|:=|/=|>=|<=|<<|>>|<>"),
+PATTERNS("dts",
+	 "!;\n"
+	 /* lines beginning with a word optionally preceded by '&' or the root */
+	 "^[ \t]*((/|&?[a-zA-Z_]).*)",
+	 /* -- */
+	 /* Property names and math operators */
+	 "[a-zA-Z0-9,._+?#-]+"
+	 "|[-+*/%&^|!~]|>>|<<|&&|\\|\\|"),
 IPATTERN("fortran",
 	 "!^([C*]|[ \t]*!)\n"
 	 "!^[ \t]*MODULE[ \t]+PROCEDURE[ \t]\n"