Git Attributes Diff Filter 配置
Diff Filter
Git diff 只能比较文本，如果能将二进制转换为文本，那么就可以实现二进制的对比。
Diff filter 在对比前将原始数据转换为文本，然后将文本内容交给 Git diff 进行差异计算:
旧原始数据 --> Diff filter --> 处理后的数据(文本) --\
> 对比
新原始数据 --> Diff filter --> 处理后的数据(文本) --/
添加一个 Diff filter
编辑 .gitattributes:
*.xx diff=your_filter
所有 *.xx 文件都需要经过 your_filter 处理，那 your_filter 去哪里找？答案是 git config:
git config diff.your_filter.textconv your_program
textconv将需要对比数据转换文本格式
可执行程序 your_program 需要满足以文件路径作为参数，并将结果打印到标准输出。
示例
PNG 元数据对比
exiftool 可以获取文件的元数据，且以文件路径为参数，结果打印到标准输出，可直接作为一个 Diff Filter：
$ exiftool 1.png
ExifTool Version Number : 12.30
File Name : 1.png
Directory : .
File Size : 244 KiB
File Modification Date/Time : 2021:09:19 21:12:58+08:00
File Access Date/Time : 2021:09:19 21:13:19+08:00
File Inode Change Date/Time : 2021:09:19 21:12:58+08:00
File Permissions : -rw-r--r--
File Type : PNG
File Type Extension : png
MIME Type : image/png
Image Width : 542
Image Height : 339
Bit Depth : 8
Color Type : RGB
Compression : Deflate/Inflate
Filter : Adaptive
Interlace : Noninterlaced
Pixels Per Unit X : 6299
Pixels Per Unit Y : 6299
Pixel Units : meters
Image Size : 542x339
Megapixels : 0.184
编辑 .gitattributes:
*.png diff=exif
- PNG 文件对比前交由
exif过滤器处理
配置 exif 过滤器:
git config diff.exif.textconv exiftool
执行 git diff 或者 git show：
diff --git a/1.png b/1.png
index 8c17513..c093c41 100644
--- a/1.png
+++ b/1.png
@@ -1,16 +1,16 @@
ExifTool Version Number : 12.30
-File Name : 4nFqmN*1.png
-Directory : /tmp
-File Size : 265 KiB
-File Modification Date/Time : 2021:09:19 21:15:24+08:00
-File Access Date/Time : 2021:09:19 21:15:24+08:00
-File Inode Change Date/Time : 2021:09:19 21:15:24+08:00
-File Permissions : -rw-------
+File Name : 1.png
+Directory : .
+File Size : 244 KiB
+File Modification Date/Time : 2021:09:19 21:12:58+08:00
+File Access Date/Time : 2021:09:19 21:15:18+08:00
+File Inode Change Date/Time : 2021:09:19 21:12:58+08:00
+File Permissions : -rw-r--r--
File Type : PNG
File Type Extension : png
MIME Type : image/png
-Image Width : 566
-Image Height : 363
+Image Width : 542
+Image Height : 339
Bit Depth : 8
Color Type : RGB
Compression : Deflate/Inflate
@@ -19,5 +19,5 @@ Interlace : Noninterlaced
Pixels Per Unit X : 6299
Pixels Per Unit Y : 6299
Pixel Units : meters
-Image Size : 566x363
-Megapixels : 0.205
+Image Size : 542x339
+Megapixels : 0.184
- 旧文件路径为
/tmp/4nFqmN*1.png，说明对比前会创建临时文件，该文件路径会作为过滤器的参数 - 元数据对比结果，而非 PNG 文件本身
十六进制方式对比
修改 .gitattributes:
*.bin diff=hex
*.bin交个过滤器hex处理
配置 hex 过滤器:
git config diff.hex.textconv "hexdump -C"
执行 git diff 或者 git show：
diff --git a/main.bin b/main.bin
index 276798a..6be8837 100755
--- a/main.bin
+++ b/main.bin
@@ -54,8 +54,8 @@
00000350 01 00 00 00 00 00 00 00 01 00 01 c0 04 00 00 00 |................|
00000360 01 00 00 00 00 00 00 00 02 00 01 c0 04 00 00 00 |................|
00000370 00 00 00 00 00 00 00 00 04 00 00 00 14 00 00 00 |................|
-00000380 03 00 00 00 47 4e 55 00 bd 9f ae 1c da ef ff 93 |....GNU.........|
-00000390 d7 cf 1d 3e 72 60 fe 7e ef ef 7f 6e 04 00 00 00 |...>r`.~...n....|
+00000380 03 00 00 00 47 4e 55 00 11 73 36 ac 4c 3f 7b b5 |....GNU..s6.L?{.|
+00000390 d4 0a f0 d1 66 78 65 d9 07 cb f1 14 04 00 00 00 |....fxe.........|
000003a0 10 00 00 00 01 00 00 00 47 4e 55 00 00 00 00 00 |........GNU.....|
000003b0 04 00 00 00 04 00 00 00 00 00 00 00 00 00 00 00 |................|
000003c0 01 00 00 00 01 00 00 00 01 00 00 00 00 00 00 00 |................|
@@ -130,7 +130,7 @@
000011e0 48 83 c4 08 c3 00 00 00 00 00 00 00 00 00 00 00 |H...............|
000011f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
-00002000 01 00 02 00 48 65 6c 6c 6f 20 57 6f 72 6c 64 21 |....Hello World!|
+00002000 01 00 02 00 48 65 6c 6c 6f 20 57 6f 72 6c 64 3f |....Hello World?|
00002010 00 00 00 00 01 1b 03 3b 30 00 00 00 05 00 00 00 |.......;0.......|
00002020 0c f0 ff ff 64 00 00 00 2c f0 ff ff 4c 00 00 00 |....d...,...L...|
00002030 25 f1 ff ff 8c 00 00 00 4c f1 ff ff ac 00 00 00 |%.......L.......|
diff --git a/main.cc b/main.cc
index d2bb6c5..6873eca 100644
--- a/main.cc
+++ b/main.cc
@@ -1,5 +1,5 @@
#include<stdio.h>
int main() {
- printf("Hello World!");
+ printf("Hello World?");
}