Re: [PATCH v1 2/2] convert: add alias support for 'working-tree-encoding' attributes

> On Jul 8, 2018, at 8:30 PM, larsxschneider@gmail.com wrote:
> 
> 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(+)
> 
> 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
> ------------------------
> 
> ...
> 
> 	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;