2 files changed, 66 insertions, 4 deletions
diff --git a/source/ui-tree.c b/source/ui-tree.c
index 8e17cc4..63b8984 100644
--- a/source/ui-tree.c
+++ b/source/ui-tree.c
@@ -17,6 +17,8 @@
 #include "ui-shared.h"
 #include "ui-tree.h"
 
+#include <odb/streaming.h>
+
 #define HEXDUMP_ROW_BYTES 32
 #define HEXDUMP_ROW_HALF (HEXDUMP_ROW_BYTES / 2)
 #define HEXDUMP_GAP_WIDTH 4
@@ -25,6 +27,10 @@
 // max-blob-size would make a page several times its own size.
 #define HEXDUMP_MAX_BYTES (64 * 1024)
 
+// How far into a buffer buffer_is_binary looks, the window git judges a file
+// binary by.
+#define BINARY_SNIFF_BYTES 8000
+
 // How many single-child directories a listing row follows into one path.
 #define MAX_DIR_CHAIN_LEVELS 15
 
@@ -147,7 +153,7 @@ static void print_binary_buffer(char *buf, size_t size, const char *path, const
  * false means a complete error page went out in place of the blob, so nothing
  * may be added to it.
  */
-static bool print_object(const struct object_id *oid, const char *path,
+static bool print_object(const struct object_id *oid, unsigned mode, const char *path,
 	const char *filename, const char *rev)
 {
 	enum object_type type;
@@ -182,7 +188,7 @@ static bool print_object(const struct object_id *oid, const char *path,
 	cgit_print_layout_start();
 	htmlf("<div class='blob-header'>blob: %s (", oid_to_hex(oid));
 	cgit_plain_link("plain", NULL, NULL, ctx.qry.head, rev, path);
-	if (ctx.repo->enable_blame && !is_binary) {
+	if (ctx.repo->enable_blame && S_ISREG(mode) && !is_binary) {
 		html(") (");
 		cgit_blame_link("blame", NULL, NULL, ctx.qry.head, rev, path);
 	}
@@ -259,6 +265,26 @@ static void print_dir_chain(const struct object_id *oid, const char *name,
 	strbuf_setlen(fullpath, initial_length);
 }
 
+/*
+ * Whether git counts the blob as binary, read through a stream so that only
+ * the bytes buffer_is_binary looks at are inflated, however large the blob.
+ */
+static bool blob_starts_binary(const struct object_id *oid)
+{
+	char buf[BINARY_SNIFF_BYTES];
+	struct odb_stream *stream;
+	size_t got = 0;
+	ssize_t n;
+
+	stream = odb_stream_from_object(the_repository->objects, oid, NULL);
+	if (!stream)
+		return false;
+	while (got < sizeof(buf) && (n = odb_stream_read(stream, buf + got, sizeof(buf) - got)) > 0)
+		got += n;
+	odb_stream_close(stream);
+	return buffer_is_binary(buf, got);
+}
+
 static void print_ls_row(const struct object_id *oid, const char *name,
 	unsigned mode, struct walk_tree_context *walk)
 {
@@ -345,7 +371,14 @@ static void print_ls_row(const struct object_id *oid, const char *name,
 		cgit_stats_link("stats", NULL, "button", ctx.qry.head, fullpath.buf);
 	if (!S_ISGITLINK(mode))
 		cgit_plain_link("plain", NULL, "button", ctx.qry.head, walk->rev, fullpath.buf);
-	if (!S_ISDIR(mode) && !S_ISGITLINK(mode) && ctx.repo->enable_blame)
+	// The blame page refuses a binary file and one past max-blob-size, so
+	// neither is offered it.
+	if (
+		S_ISREG(mode)              &&
+		ctx.repo->enable_blame     &&
+		!cgit_blob_too_large(size) &&
+		!blob_starts_binary(oid)
+	)
 		cgit_blame_link("blame", NULL, "button", ctx.qry.head, walk->rev, fullpath.buf);
 	html("</td></tr>\n");
 
@@ -438,7 +471,7 @@ static int walk_tree(const struct object_id *oid, struct strbuf *base,
 			ls_head();
 			return READ_TREE_RECURSIVE;
 		} else {
-			bool shown = print_object(oid, fullpath.buf, pathname, walk->rev);
+			bool shown = print_object(oid, mode, fullpath.buf, pathname, walk->rev);
 
 			walk->state = shown ? WALK_BLOB_SHOWN : WALK_ERROR_SHOWN;
 			strbuf_release(&fullpath);
diff --git a/tests/t0104-tree.sh b/tests/t0104-tree.sh
index 490abb3..ca29bdc 100755
--- a/tests/t0104-tree.sh
+++ b/tests/t0104-tree.sh
@@ -190,6 +190,17 @@ test_expect_success 'only a link target inside the tree is linked' '
 	! grep "href=./links/tree/etc/passwd" tmp
 '
 
+# Blame takes a regular file alone, so a symlink is not offered it.
+test_expect_success 'a symlink is not offered blame' '
+	cgitrc_repo linksblamerc links enable-blame=1 &&
+	cgit_rc linksblamerc "url=links/tree/" >tmp &&
+	grep "href=./links/blame/target.txt.>blame</a>" tmp &&
+	! grep "href=./links/blame/rel.>blame</a>" tmp &&
+	cgit_rc linksblamerc "url=links/tree/rel" >tmp &&
+	grep "<div class=.blob-header.>" tmp &&
+	! grep ">blame</a>" tmp
+'
+
 # A row follows a chain of single directories for a set number of levels and
 # stops on the last one it links, with no separator left hanging after it.
 test_expect_success 'a long directory chain ends on a link' '
@@ -265,4 +276,22 @@ test_expect_success 'a large binary is dumped only in part' '
 	grep "<div class=.truncated.>Only the first 64 KB of this file are shown. <a href=./bin/plain/big.bin.>View the whole file</a>.</div>" tmp
 '
 
+# The blame page refuses a file git counts as binary and one past
+# max-blob-size, so a listing offers blame for neither.
+test_expect_success 'a listing offers blame only where it works' '
+	(
+		cd repos/bin &&
+		echo hello >small.txt &&
+		test_seq 1 2000 >large.txt &&
+		git add small.txt large.txt &&
+		git commit -m "text files"
+	) &&
+	cgitrc_repo binblamerc bin enable-blame=1 max-blob-size=4 &&
+	cgit_rc binblamerc "url=bin/tree/" >tmp &&
+	grep "href=./bin/blame/small.txt.>blame</a>" tmp &&
+	! grep "href=./bin/blame/large.txt.>blame</a>" tmp &&
+	! grep "href=./bin/blame/blob.bin.>blame</a>" tmp &&
+	! grep "href=./bin/blame/big.bin.>blame</a>" tmp
+'
+
 test_done