color: Compare values too when deciding to smart-case

src/color.c

@@ -42,8 +42,8 @@ struct ext_color {
  struct esc_seq *esc;
  /** The length of the extension to match. */
  size_t len;
- /** Whether the comparison should be case-insensitive. */
- bool icase;
+ /** Whether the comparison should be case-sensitive. */
+ bool case_sensitive;
  /** The extension to match (NUL-terminated). */
  char ext[];
 };
@@ -147,6 +147,11 @@ static int init_esc(struct colors *colors, const char *name, const char *value,
  }
 }
 
+/** Check if an escape sequence is equal to a string. */
+static bool esc_eq(const struct esc_seq *esc, const char *str, size_t len) {
+ return esc->len == len && memcmp(esc->seq, str, len) == 0;
+}
+
 /** Get an escape sequence from the table. */
 static struct esc_seq **get_esc(const struct colors *colors, const char *name) {
  const struct trie_leaf *leaf = trie_find_str(&colors->names, name);
@@ -204,6 +209,55 @@ static void ext_tolower(char *ext, size_t len) {
 /** Maximum supported extension length. */
 #define EXT_MAX 255
 
+/**
+ * The "smart case" algorithm.
+ *
+ * @param ext
+ * The current extension being added.
+ * @param prev
+ * The previous case-sensitive match, if any, for the same extension.
+ * @param iprev
+ * The previous case-insensitive match, if any, for the same extension.
+ * @return
+ * Whether this extension should become case-sensitive.
+ */
+static bool ext_case_sensitive(struct ext_color *ext, struct ext_color *prev, struct ext_color *iprev) {
+ // This is the first case-insensitive occurrence of this extension, e.g.
+ //
+ // *.gz=01;31:*.tar.gz=01;33
+ if (!iprev) {
+ bfs_assert(!prev);
+ return false;
+ }
+
+ // If the last version of this extension is already case-sensitive,
+ // this one should be too, e.g.
+ //
+ // *.tar.gz=01;31:*.TAR.GZ=01;32:*.TAR.GZ=01;33
+ if (iprev->case_sensitive) {
+ return true;
+ }
+
+ // The case matches the last occurrence exactly, e.g.
+ //
+ // *.tar.gz=01;31:*.tar.gz=01;33
+ if (iprev == prev) {
+ return false;
+ }
+
+ // Different case, but same value, e.g.
+ //
+ // *.tar.gz=01;31:*.TAR.GZ=01;31
+ if (esc_eq(iprev->esc, ext->esc->seq, ext->esc->len)) {
+ return false;
+ }
+
+ // Different case, different value, e.g.
+ //
+ // *.tar.gz=01;31:*.TAR.GZ=01;33
+ return true;
+}
+
 /** Set the color for an extension. */
 static int set_ext(struct colors *colors, char *key, char *value) {
  size_t len = dstrlen(key);
@@ -214,7 +268,7 @@ static int set_ext(struct colors *colors, char *key, char *value) {
 
  ext->priority = colors->ext_count++;
  ext->len = len;
- ext->icase = true;
+ ext->case_sensitive = false;
  ext->esc = new_esc(colors, value, dstrlen(value));
  if (!ext->esc) {
  goto fail;
@@ -253,12 +307,10 @@ static int set_ext(struct colors *colors, char *key, char *value) {
  goto fail;
  }
 
- // If a match for the lowercased extension exists and is different from
- // the exact match, or is already case-sensitive, mark this one too
  struct ext_color *iprev = leaf->value;
- if (iprev && (iprev != prev || !iprev->icase)) {
- iprev->icase = false;
- ext->icase = false;
+ if (ext_case_sensitive(ext, prev, iprev)) {
+ iprev->case_sensitive = true;
+ ext->case_sensitive = true;
  }
  leaf->value = ext;
 
@@ -279,14 +331,14 @@ static int build_iext_trie(struct colors *colors) {
 
  TRIE_FOR_EACH(&colors->ext_trie, leaf) {
  struct ext_color *ext = leaf->value;
- if (!ext->icase) {
+ if (ext->case_sensitive) {
  continue;
  }
 
  // set_ext() already reversed and lowercased the extension
  struct trie_leaf *ileaf;
  while ((ileaf = trie_find_postfix(&colors->iext_trie, ext->ext))) {
- trie_remove(&colors->ext_trie, ileaf);
+ trie_remove(&colors->iext_trie, ileaf);
  }
 
  ileaf = trie_insert_str(&colors->iext_trie, ext->ext);
@@ -616,12 +668,9 @@ struct colors *parse_colors(void) {
  goto fail;
  }
 
- if (colors->link) {
- size_t len = strlen("target");
- if (colors->link->len == len && memcmp(colors->link->seq, "target", len) == 0) {
- colors->link_as_target = true;
- colors->link->len = 0;
- }
+ if (colors->link && esc_eq(colors->link, "target", strlen("target"))) {
+ colors->link_as_target = true;
+ colors->link->len = 0;
  }
 
  return colors;

tests/bfs/color_ext_case.out

@@ -16,10 +16,10 @@
 rainbow/sgid
 rainbow/pipe
 rainbow/ow
+rainbow/file.txt
 rainbow/sugid
 rainbow/suid
 rainbow/sticky
 rainbow/file.dat
-rainbow/file.txt
 rainbow/mh1
 rainbow/mh2

tests/bfs/color_ext_case.sh

@@ -1 +1,6 @@
-LS_COLORS="*.gz=01;31:*.GZ=01;32:*.tAr=01;33:*.TAR.gz=01;34:*.tar.GZ=01;35:" bfs_diff rainbow -color
+# *.gz=01;31:*.GZ=01;32 -- case sensitive
+# *.tAr=01;33:*.TaR=01;33 -- case-insensitive
+# *.TAR.gz=01;34:*.tar.GZ=01;35 -- case-sensitive
+# *.txt=35:*TXT=36 -- case-insensitive
+export LS_COLORS="*.gz=01;31:*.GZ=01;32:*.tAr=01;33:*.TaR=01;33:*.TAR.gz=01;34:*.tar.GZ=01;35:*.txt=35:*TXT=36"
+bfs_diff rainbow -color