[PATCH v1 2/2] convert: add alias support for 'working-tree-encoding' attributes
From: Lars Schneider <larsxschneider@gmail.com>
In 107642fe26 ("convert: add 'working-tree-encoding' attribute", 2018-04-15) we added an attribute which defines the working tree encoding of a file.
Some platforms might spell the name of a certain encoding differently or some users might want to use different encodings on different platforms. Add the Git config "encoding.<iconv-name>.insteadOf = <alias-name>" to support these use-cases with a user specific mapping. If the alias matches an existing encoding name, then the alias will take precedence. The alias is case insensitive.
Example:
(in .gitattributes)
*.c working-tree-encoding=foo
(in config)
[encoding "UTF-16"]
insteadOf = foo
Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---
Documentation/gitattributes.txt | 19 ++++++++++++
convert.c | 50 ++++++++++++++++++++++++++++++++
t/t0028-working-tree-encoding.sh | 28 ++++++++++++++++++
3 files changed, 97 insertions(+)
Show changes to 3 files +97 −0
Documentation/gitattributes.txt, convert.c, t/t0028-working-tree-encoding.sh
diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 92010b062e..3628f0e5cf 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -366,6 +366,25 @@ command to guess the encoding:
file foo.ps1
------------------------
+The encoding in all examples above was directly defined in the Git
+attributes. In addition, it is possible to define encodings indirectly
+using aliases set via Git config:
+
+------------------------
+[encoding "UTF-16"]
+ insteadOf = my-custom-alias
+------------------------
+
+The alias name can be used in the Git attributes instead of the actual
+encoding name:
+
+------------------------
+*.ps1 text working-tree-encoding=my-custom-alias
+------------------------
+
+This mapping can be useful if equivalent encodings are spelled
+differently across platforms. It can also be useful if a user wants to
+use different encodings on different platforms for the same file.
`ident`
^^^^^^^
diff --git a/convert.c b/convert.c
index 949bc783e4..4f19ce1a04 100644
--- a/convert.c
+++ b/convert.c
@@ -997,6 +997,15 @@ static int apply_filter(const char *path, const char *src, size_t len,
return 0;
}
+struct alias2enc {
+ struct hashmap_entry ent; /* must be the first member! */
+ const char *alias;
+ const char *encoding;
+};
+
+static int encoding_aliases_initialized;
+static struct hashmap encoding_map;
+
static int read_convert_config(const char *var, const char *value, void *cb)
{
const char *key, *name;
@@ -1040,6 +1049,36 @@ static int read_convert_config(const char *var, const char *value, void *cb)
drv->required = git_config_bool(var, value);
return 0;
}
+ } else if (
+ parse_config_key(var, "encoding", &name, &namelen, &key) >= 0 &&
+ name && !strcmp(key, "insteadof")) {
+ /*
+ * Encoding aliases are configured using
+ * "encoding.<iconv-name>.insteadOf = <alias-name>".
+ */
+ struct alias2enc *entry;
+ if (!value)
+ return config_error_nonbool(key);
+
+ if (!encoding_aliases_initialized) {
+ encoding_aliases_initialized = 1;
+ hashmap_init(&encoding_map, NULL, NULL, 0);
+ entry = NULL;
+ } else {
+ struct alias2enc hashkey;
+ hashmap_entry_init(&hashkey, strihash(value));
+ hashkey.alias = value;
+ entry = hashmap_get(&encoding_map, &hashkey, NULL);
+ }
+
+ if (!entry) {
+ entry = xmalloc(sizeof(*entry));
+ entry->encoding = xstrndup(name, namelen);
+ entry->alias = xstrdup(value);
+
+ hashmap_entry_init(entry, strihash(value));
+ hashmap_add(&encoding_map, entry);
+ }
}
return 0;
@@ -1225,6 +1264,17 @@ static const char *git_path_check_encoding(struct attr_check_item *check)
die(_("true/false are no valid working-tree-encodings"));
}
+ /* Check if an alias was defined for the encoding in the Git config */
+ if (encoding_aliases_initialized) {
+ struct alias2enc hashkey;
+ struct alias2enc *entry;
+ hashmap_entry_init(&hashkey, strihash(value));
+ hashkey.alias = value;
+ entry = hashmap_get(&encoding_map, &hashkey, NULL);
+ if (entry)
+ value = entry->encoding;
+ }
+
/* Don't encode to the default encoding */
if (same_encoding(value, default_encoding))
return NULL;
diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh
index 12b8eb963a..d803e00cbe 100755
--- a/t/t0028-working-tree-encoding.sh
+++ b/t/t0028-working-tree-encoding.sh
@@ -242,4 +242,32 @@ test_expect_success 'check roundtrip encoding' '
git reset
'
+test_expect_success 'encoding alias' '
+ test_when_finished "rm -f test.foo16.git test.foo8" &&
+ test_when_finished "git reset --hard HEAD" &&
+
+ test_config encoding.UTF-16.InsteadOf foo16 &&
+
+ text="hallo there!\ncan you read me with an alias?" &&
+ printf "$text" >test.foo8 &&
+ printf "$text" | iconv -f UTF-8 -t UTF-16 >test.foo16 &&
+
+ echo "*.foo16 text working-tree-encoding=fOO16" >.gitattributes &&
+ git add test.foo16 .gitattributes &&
+
+ git cat-file -p :test.foo16 >test.foo16.git &&
+ test_cmp_bin test.foo8 test.foo16.git
+'
+
+test_expect_success 'encoding alias overwrites existing encoding' '
+ test_when_finished "git reset --hard HEAD" &&
+
+ test_config encoding.CONFUSE.insteadOf UTF-16 &&
+
+ echo "*.garbage text working-tree-encoding=UTF-16" >.gitattributes &&
+ printf "garbage" >t.garbage &&
+ test_must_fail git add t.garbage 2>err.out &&
+ test_i18ngrep "failed to encode .* from CONFUSE to UTF-8" err.out
+'
+
test_done
--
2.18.0
larsxschneider@gmail.com