Display SSH completion candidates for ambiguous prefixes

src/console_completion.c

@@ -270,6 +270,47 @@ bool console_completion_expand(const char *line, char *completed, size_t capacit
     return true;
 }
 
+typedef struct {
+    char *output;
+    size_t capacity;
+    size_t length;
+    bool complete;
+} completion_format_context_t;
+
+static bool format_completion_candidate(const char *candidate, void *context)
+{
+    completion_format_context_t *result = context;
+    size_t candidate_length = strlen(candidate);
+    if (candidate_length + 2U > result->capacity - result->length) {
+        result->complete = false;
+        return false;
+    }
+    memcpy(result->output + result->length, candidate, candidate_length);
+    result->length += candidate_length;
+    result->output[result->length++] = '\r';
+    result->output[result->length++] = '\n';
+    return true;
+}
+
+bool console_completion_format_matches(const char *line, char *output, size_t capacity,
+                                       size_t *output_length)
+{
+    if (line == NULL || output == NULL || output_length == NULL || capacity == 0U) {
+        return false;
+    }
+    completion_format_context_t result = {
+        .output = output,
+        .capacity = capacity,
+        .complete = true,
+    };
+    console_completion_visit(line, format_completion_candidate, &result);
+    if (!result.complete) {
+        return false;
+    }
+    *output_length = result.length;
+    return true;
+}
+
 static ssize_t console_read_with_late_terminal_upgrade(int file_descriptor,
                                                        void *buffer,
                                                        size_t size)