[glib: 1/2] guri: Preallocate a buffer for building URIs

[Philip Withnall <pwithnall src gnome org>]

commit 17f608e382aedb892239fa381dc13fe2b614f74a
Author: Philip Withnall <pwithnall endlessos org>
Date:   Thu May 5 13:38:44 2022 +0100

    guri: Preallocate a buffer for building URIs
    
    Rather than reallocating the string buffer a few times as more
    components are added, use a default buffer size which should hopefully
    accommodate most average URIs.
    
    The buffer size is a guess and can be tweaked in future.
    
    This has the advantage of no longer passing a potentially-`NULL`
    `scheme` to `g_string_new()`, which should placate the static analysers,
    which think that `g_string_new()` shouldn’t accept `NULL`.
    
    Signed-off-by: Philip Withnall <pwithnall endlessos org>
    
    Coverity CID: #1474691

 glib/guri.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/glib/guri.c b/glib/guri.c
index 069060809a..a698b07ed5 100644
--- a/glib/guri.c
+++ b/glib/guri.c
@@ -1633,9 +1633,17 @@ g_uri_join_internal (GUriFlags    flags,
   g_return_val_if_fail (host == NULL || (path[0] == '\0' || path[0] == '/'), NULL);
   g_return_val_if_fail (host != NULL || (path[0] != '/' || path[1] != '/'), NULL);
 
-  str = g_string_new (scheme);
+  /* Arbitrarily chosen default size which should handle most average length
+   * URIs. This should avoid a few reallocations of the buffer in most cases.
+   * It’s 1B shorter than a power of two, since GString will add a
+   * nul-terminator byte. */
+  str = g_string_sized_new (127);
+
   if (scheme)
-    g_string_append_c (str, ':');
+    {
+      g_string_append (str, scheme);
+      g_string_append_c (str, ':');
+    }
 
   if (flags & G_URI_FLAGS_SCHEME_NORMALIZE && scheme && ((host && port != -1) || path[0] == '\0'))
     normalized_scheme = g_ascii_strdown (scheme, -1);