[PATCH v10 8/9] convert: add tracing for 'working-tree-encoding' attribute

[lars . schneider]

From: Lars Schneider <larsxschnei...@gmail.com>

Add the GIT_TRACE_WORKING_TREE_ENCODING environment variable to enable
tracing for content that is reencoded with the 'working-tree-encoding'
attribute. This is useful to debug encoding issues.

Signed-off-by: Lars Schneider <larsxschnei...@gmail.com>
---
 convert.c                        | 25 +++++++++++++++++++++++++
 t/t0028-working-tree-encoding.sh |  2 ++
 2 files changed, 27 insertions(+)

diff --git a/convert.c b/convert.c
index f19a15dd02..5776dfbc99 100644
--- a/convert.c
+++ b/convert.c
@@ -318,6 +318,29 @@ static int validate_encoding(const char *path, const char 
*enc,
        return 0;
 }
 
+static void trace_encoding(const char *context, const char *path,
+                          const char *encoding, const char *buf, size_t len)
+{
+       static struct trace_key coe = TRACE_KEY_INIT(WORKING_TREE_ENCODING);
+       struct strbuf trace = STRBUF_INIT;
+       int i;
+
+       strbuf_addf(&trace, "%s (%s, considered %s):\n", context, path, 
encoding);
+       for (i = 0; i < len && buf; ++i) {
+               strbuf_addf(
+                       &trace,"| \e[2m%2i:\e[0m %2x \e[2m%c\e[0m%c",
+                       i,
+                       (unsigned char) buf[i],
+                       (buf[i] > 32 && buf[i] < 127 ? buf[i] : ' '),
+                       ((i+1) % 8 && (i+1) < len ? ' ' : '\n')
+               );
+       }
+       strbuf_addchars(&trace, '\n', 1);
+
+       trace_strbuf(&coe, &trace);
+       strbuf_release(&trace);
+}
+
 static const char *default_encoding = "UTF-8";
 
 static int encode_to_git(const char *path, const char *src, size_t src_len,
@@ -346,6 +369,7 @@ static int encode_to_git(const char *path, const char *src, 
size_t src_len,
        if (validate_encoding(path, enc, src, src_len, die_on_error))
                return 0;
 
+       trace_encoding("source", path, enc, src, src_len);
        dst = reencode_string_len(src, src_len, default_encoding, enc,
                                  &dst_len);
        if (!dst) {
@@ -363,6 +387,7 @@ static int encode_to_git(const char *path, const char *src, 
size_t src_len,
                        return 0;
                }
        }
+       trace_encoding("destination", path, default_encoding, dst, dst_len);
 
        strbuf_attach(buf, dst, dst_len, dst_len + 1);
        return 1;
diff --git a/t/t0028-working-tree-encoding.sh b/t/t0028-working-tree-encoding.sh
index aa05f82166..6f3a82f61b 100755
--- a/t/t0028-working-tree-encoding.sh
+++ b/t/t0028-working-tree-encoding.sh
@@ -4,6 +4,8 @@ test_description='working-tree-encoding conversion via 
gitattributes'
 
 . ./test-lib.sh
 
+GIT_TRACE_WORKING_TREE_ENCODING=1 && export GIT_TRACE_WORKING_TREE_ENCODING
+
 test_expect_success 'setup test files' '
        git config core.eol lf &&
 
-- 
2.16.2