[ostree] static-delta: Add --disable-bsdiff option

[Colin Walters <walters src gnome org>]

commit 392929d9bc3362854ec50d9a7456f410a167580c
Author: Colin Walters <walters verbum org>
Date:   Mon Mar 2 18:31:23 2015 -0500

    static-delta: Add --disable-bsdiff option
    
    A builder may not want to pay the CPU penalty.  Also it's useful for
    evaluating performance.

 .../ostree-repo-static-delta-compilation.c         |   29 +++++++++++++++----
 src/ostree/ot-builtin-static-delta.c               |    5 +++
 2 files changed, 28 insertions(+), 6 deletions(-)
---
diff --git a/src/libostree/ostree-repo-static-delta-compilation.c 
b/src/libostree/ostree-repo-static-delta-compilation.c
index a4e7ae4..5232aa2 100644
--- a/src/libostree/ostree-repo-static-delta-compilation.c
+++ b/src/libostree/ostree-repo-static-delta-compilation.c
@@ -848,10 +848,16 @@ process_one_bsdiff (OstreeRepo                       *repo,
   return ret;
 }
 
+typedef enum {
+  DELTAOPT_FLAG_NONE = (1 << 0),
+  DELTAOPT_FLAG_DISABLE_BSDIFF = (1 << 1)
+} DeltaOpts;
+
 static gboolean 
 generate_delta_lowlatency (OstreeRepo                       *repo,
                            const char                       *from,
                            const char                       *to,
+                           DeltaOpts                         opts,
                            OstreeStaticDeltaBuilder         *builder,
                            GCancellable                     *cancellable,
                            GError                          **error)
@@ -988,12 +994,15 @@ generate_delta_lowlatency (OstreeRepo                       *repo,
           continue;
         }
 
-      if (!try_content_bsdiff (repo, from_checksum, to_checksum,
-                               &bsdiff, cancellable, error))
-        goto out;
+      if (!(opts & DELTAOPT_FLAG_DISABLE_BSDIFF))
+        {
+          if (!try_content_bsdiff (repo, from_checksum, to_checksum,
+                                   &bsdiff, cancellable, error))
+            goto out;
 
-      if (bsdiff)
-        g_hash_table_insert (bsdiff_optimized_content_objects, g_strdup (to_checksum), bsdiff);
+          if (bsdiff)
+            g_hash_table_insert (bsdiff_optimized_content_objects, g_strdup (to_checksum), bsdiff);
+        }
     }
 
   g_printerr ("rollsum for %u/%u modified\n",
@@ -1215,6 +1224,7 @@ ostree_repo_static_delta_generate (OstreeRepo                   *self,
   guint min_fallback_size;
   guint max_chunk_size;
   GVariant *metadata_source;
+  DeltaOpts delta_opts = DELTAOPT_FLAG_NONE;
   guint64 total_compressed_size = 0;
   guint64 total_uncompressed_size = 0;
   gs_unref_variant_builder GVariantBuilder *part_headers = NULL;
@@ -1238,12 +1248,19 @@ ostree_repo_static_delta_generate (OstreeRepo                   *self,
     max_chunk_size = 32;
   builder.max_chunk_size_bytes = ((guint64)max_chunk_size) * 1000 * 1000;
 
+  { gboolean use_bsdiff;
+    if (!g_variant_lookup (params, "bsdiff-enabled", "b", &use_bsdiff))
+      use_bsdiff = TRUE;
+    if (!use_bsdiff)
+      delta_opts |= DELTAOPT_FLAG_DISABLE_BSDIFF;
+  }
+
   if (!ostree_repo_load_variant (self, OSTREE_OBJECT_TYPE_COMMIT, to,
                                  &to_commit, error))
     goto out;
 
   /* Ignore optimization flags */
-  if (!generate_delta_lowlatency (self, from, to, &builder,
+  if (!generate_delta_lowlatency (self, from, to, delta_opts, &builder,
                                   cancellable, error))
     goto out;
 
diff --git a/src/ostree/ot-builtin-static-delta.c b/src/ostree/ot-builtin-static-delta.c
index 4c35dc6..0a53aaf 100644
--- a/src/ostree/ot-builtin-static-delta.c
+++ b/src/ostree/ot-builtin-static-delta.c
@@ -33,6 +33,7 @@ static char *opt_gpg_homedir;
 static char *opt_min_fallback_size;
 static char *opt_max_chunk_size;
 static gboolean opt_empty;
+static gboolean opt_disable_bsdiff;
 
 #define BUILTINPROTO(name) static gboolean ot_static_delta_builtin_ ## name (int argc, char **argv, 
GCancellable *cancellable, GError **error)
 
@@ -54,6 +55,7 @@ static GOptionEntry generate_options[] = {
   { "from", 0, 0, G_OPTION_ARG_STRING, &opt_from_rev, "Create delta from revision REV", "REV" },
   { "empty", 0, 0, G_OPTION_ARG_NONE, &opt_empty, "Create delta from scratch", NULL },
   { "to", 0, 0, G_OPTION_ARG_STRING, &opt_to_rev, "Create delta to revision REV", "REV" },
+  { "disable-bsdiff", 0, 0, G_OPTION_ARG_NONE, &opt_disable_bsdiff, "Disable use of bsdiff", NULL },
   { "gpg-sign", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_key_ids, "GPG Key ID to sign the delta with", 
"key-id"},
   { "gpg-homedir", 0, 0, G_OPTION_ARG_STRING, &opt_gpg_homedir, "GPG Homedir to use when looking for 
keyrings", "homedir"},
   { "min-fallback-size", 0, 0, G_OPTION_ARG_STRING, &opt_min_fallback_size, "Minimum uncompressed size in 
megabytes for individual HTTP request", NULL},
@@ -192,6 +194,9 @@ ot_static_delta_builtin_generate (int argc, char **argv, GCancellable *cancellab
       if (opt_max_chunk_size)
         g_variant_builder_add (parambuilder, "{sv}",
                                "max-chunk-size", g_variant_new_uint32 (g_ascii_strtoull (opt_max_chunk_size, 
NULL, 10)));
+      if (opt_disable_bsdiff)
+        g_variant_builder_add (parambuilder, "{sv}",
+                               "bsdiff-enabled", g_variant_new_boolean (FALSE));
 
       g_print ("Generating static delta:\n");
       g_print ("  From: %s\n", from_resolved ? from_resolved : "empty");