From eca5e4598a8d6623acb30e28bb023186d8f69bcc Mon Sep 17 00:00:00 2001
From: Lancelot SIX <lancelot@lancleotsix.com>
Date: Sat, 23 Nov 2013 12:03:55 +0100
Subject: [PATCH] libi3/root_atom_contents: handle data of arbitrary length

Handle data fetched from xcb_get_property_unchecked with arbitrary
length. This avoids having to rely on PATH_MAX macro where it is not
necessary.
---
 common.mk                  |  2 +-
 libi3/root_atom_contents.c | 18 +++++++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/common.mk b/common.mk
index 0214abfa..e3c92fa1 100644
--- a/common.mk
+++ b/common.mk
@@ -144,7 +144,7 @@ PANGO_LIBS   := $(call ldflags_for_lib, cairo)
 PANGO_LIBS   += $(call ldflags_for_lib, pangocairo)
 
 # libi3
-LIBS = -L$(TOPDIR) -li3
+LIBS = -L$(TOPDIR) -li3 -lm
 
 ## Platform-specific flags
 
diff --git a/libi3/root_atom_contents.c b/libi3/root_atom_contents.c
index 236f1b99..00b74005 100644
--- a/libi3/root_atom_contents.c
+++ b/libi3/root_atom_contents.c
@@ -10,6 +10,7 @@
 #include <stdbool.h>
 #include <limits.h>
 #include <stdlib.h>
+#include <math.h>
 
 #include <xcb/xcb.h>
 #include <xcb/xcb_aux.h>
@@ -31,6 +32,7 @@ char *root_atom_contents(const char *atomname, xcb_connection_t *provided_conn,
     xcb_intern_atom_cookie_t atom_cookie;
     xcb_intern_atom_reply_t *atom_reply;
     char *content;
+    size_t content_max_words = 256;
     xcb_connection_t *conn = provided_conn;
 
     if (provided_conn == NULL &&
@@ -50,12 +52,26 @@ char *root_atom_contents(const char *atomname, xcb_connection_t *provided_conn,
     xcb_get_property_cookie_t prop_cookie;
     xcb_get_property_reply_t *prop_reply;
     prop_cookie = xcb_get_property_unchecked(conn, false, root, atom_reply->atom,
-                                             XCB_GET_PROPERTY_TYPE_ANY, 0, PATH_MAX);
+                                             XCB_GET_PROPERTY_TYPE_ANY, 0, content_max_words);
     prop_reply = xcb_get_property_reply(conn, prop_cookie, NULL);
     if (prop_reply == NULL) {
         free(atom_reply);
         return NULL;
     }
+    if (xcb_get_property_value_length(prop_reply) > 0 && prop_reply->bytes_after > 0) {
+        /* We received an incomplete value. Ask again but with a properly
+         * adjusted size. */
+        content_max_words += ceil(prop_reply->bytes_after / 4.0);
+        /* Repeat the request, with adjusted size */
+        free(prop_reply);
+        prop_cookie = xcb_get_property_unchecked(conn, false, root, atom_reply->atom,
+                                                 XCB_GET_PROPERTY_TYPE_ANY, 0, content_max_words);
+        prop_reply = xcb_get_property_reply(conn, prop_cookie, NULL);
+        if (prop_reply == NULL) {
+            free(atom_reply);
+            return NULL;
+        }
+    }
     if (xcb_get_property_value_length(prop_reply) == 0) {
         free(atom_reply);
         free(prop_reply);