[aisleriot] cards: Add svgcrush utility

[Christian Persch <chpe src gnome org>]

commit 41038e7b15b36b7357cfb85053c184314dc56c56
Author: Christian Persch <chpe gnome org>
Date:   Wed Dec 7 23:09:24 2011 +0100

    cards: Add svgcrush utility
    
    Add noinst utility programme that takes a SVG with embedded (data:image/png;base64)
    PNGs, uses pngcrush to crush these and re-save the SVG. Need to "make svgcrush" manually
    to build it, it's not hooked up to any targets. E.g.:
    
    $ make svgcrush
    $ ./svgcrush bonded.svg bonded-crushed.svg

 cards/Makefile.am |    9 ++
 cards/svgcrush.c  |  273 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 282 insertions(+), 0 deletions(-)
---
diff --git a/cards/Makefile.am b/cards/Makefile.am
index 9af80c5..30cfca3 100644
--- a/cards/Makefile.am
+++ b/cards/Makefile.am
@@ -38,4 +38,13 @@ DISTCLEANFILES = \
 %.svgz: %.svg
 	$(AM_V_GEN)$(XMLLINT) $(XMLLINT_FLAGS) $< | $(GZIP) $(GZIP_FLAGS) > $@
 
+# SVG crush utility
+
+svgcrush: svgcrush.c Makefile
+	$(AM_V_GEN) $(CC) `$(PKG_CONFIG) --libs --cflags glib-2.0 libxml-2.0` $(AM_CPPFLAGS) $(AM_CFLAGS) $(AM_LDFLAGS) -o $@ $<
+
+EXTRA_DIST += svgcrush.c
+
+# .gitignore
+
 -include $(top_srcdir)/git.mk
diff --git a/cards/svgcrush.c b/cards/svgcrush.c
new file mode 100644
index 0000000..11ab99d
--- /dev/null
+++ b/cards/svgcrush.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright  2011 Christian Persch
+ *
+ * This programme is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This programme is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this programme.  If not, see <http://www.gnu.org/licenses/>. 
+ */
+
+#include <glib.h>
+
+#include <libxml/parser.h>
+#include <libxml/xpath.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/wait.h>
+
+#ifdef KEEP_TEMPFILES
+#define UNLINK(s)
+#else
+#define UNLINK(s) unlink((s))
+#endif
+
+static char *pngcrush;
+
+static char *
+decode (const char *content,
+        gsize *len)
+{
+  const char *comma;
+  char *content_type;
+  char **split;
+  gboolean is_base64;
+  int i;
+
+  content += strlen ("data:");
+  comma = strchr (content, ',');
+  if (comma == NULL)
+    return NULL;
+
+  content_type = g_strndup (content, comma - content);
+  split = g_strsplit (content_type, ";", -1);
+  g_free (content_type);
+  if (split == NULL)
+    return NULL;
+  if (strcmp (split[0], "image/png") != 0) {
+    g_strfreev (split);
+    return NULL;
+  }
+
+  is_base64 = FALSE;
+  for (i = 1; split[i]; ++i)
+    if (strcmp (split[i], "base64") == 0) {
+      is_base64 = TRUE;
+      break;
+    }
+  g_strfreev (split);
+
+  if (!is_base64)
+    return NULL;
+
+  content = comma + 1;
+  return (char *) g_base64_decode (content, len);
+}
+
+static char *
+save (const char *content,
+      gsize *len)
+{
+  char *decoded;
+  char *filename;
+  int fd;
+
+  decoded = decode (content, len);
+  if (decoded == NULL)
+    return NULL;
+
+  filename = g_strdup ("./svg-crush-XXXXXXXX");
+  fd = g_mkstemp (filename);
+  if (fd == -1 ||
+      !g_file_set_contents (filename, decoded, *len, NULL)) {
+    g_free (filename);
+    g_free (decoded);
+    return NULL;
+  }
+
+  g_free (decoded);
+  return filename;
+}
+
+static void
+shutup (gpointer data G_GNUC_UNUSED)
+{
+  close (STDIN_FILENO);
+  close (STDOUT_FILENO);
+  close (STDERR_FILENO);
+}
+
+static char *
+crush (const char *tmp_in,
+       gsize *len)
+{
+  char *tmp_out;
+  char *contents = NULL;
+  int fd, status;
+  gboolean retval;
+  char *argv[4];
+
+  tmp_out = g_strdup ("svg-crush-XXXXXXXX");
+  fd = g_mkstemp (tmp_out);
+  if (fd == -1) {
+    g_free (tmp_out);
+    return NULL;
+  }
+  close (fd);
+
+  argv[0] = pngcrush;
+  argv[1] = (char *) tmp_in;
+  argv[2] = tmp_out;
+  argv[3] = NULL;
+  retval = g_spawn_sync (NULL /* our cwd */,
+                         argv,
+                         NULL /* envv */,
+                         0,
+                         shutup /* pngcrush is very noisy */, NULL,
+                         NULL /* stdin */, NULL /* stdout */,
+                         &status,
+                         NULL);
+  if (!retval || !WIFEXITED (status) || WEXITSTATUS (status) != 0)
+    goto out;
+
+  if (!g_file_get_contents (tmp_out, &contents, len, NULL))
+    contents = NULL;
+
+  /* pngcrush sometimes exits with status 0 but writes a zero-length file */
+  if (*len == 0) {
+    g_free (contents);
+    contents = NULL;
+  }
+
+out:
+  UNLINK (tmp_out);
+  g_free (tmp_out);
+
+  return contents;
+}
+
+static char*
+encode (const char *content,
+        gsize len)
+{
+  char *encoded, *data;
+
+  encoded = g_base64_encode ((const guchar *) content, len);
+  data = g_strconcat ("data:image/png;base64,", encoded, NULL);
+  g_free (encoded);
+
+  return data;
+}
+
+static void
+process (xmlNodePtr node)
+{
+  char *tmp_in;
+  gsize in_len, out_len;
+  char *crushed, *encoded;
+
+  tmp_in = save ((const char *) node->content, &in_len);
+  if (tmp_in == NULL)
+    return;
+
+  crushed = crush (tmp_in, &out_len);
+  if (crushed == NULL)
+    goto out;
+
+  encoded = encode (crushed, out_len);
+  xmlNodeSetContent (node, (const xmlChar *) encoded);
+  g_free (encoded);
+
+  g_print ("OUT %" G_GSIZE_FORMAT " / IN %" G_GSIZE_FORMAT " = %.1f%%\n",
+           out_len, in_len, 100. * (double) out_len / (double) in_len);
+
+out:
+  UNLINK (tmp_in);
+  g_free (tmp_in);
+}
+
+static gboolean
+transform (xmlDocPtr doc)
+{
+  gboolean retval = FALSE;
+  xmlXPathContextPtr ctx;
+  xmlXPathObjectPtr obj;
+  xmlNodeSetPtr set;
+  xmlNodePtr *nodes;
+  int i, n_nodes;
+
+  ctx = xmlXPathNewContext (doc);
+
+  obj = xmlXPathEvalExpression ((const xmlChar *) "//*/@*[namespace-uri()='http://www.w3.org/1999/xlink']", ctx);
+  if (obj == NULL || obj->type != XPATH_NODESET)
+    goto out;
+
+  set = obj->nodesetval;
+  nodes = set->nodeTab;
+  n_nodes = set->nodeNr;
+
+  for (i = 0; i < n_nodes; ++i) {
+    xmlNodePtr child = nodes[i]->children;
+
+    if (child == NULL ||
+        child->content == NULL)
+      continue;
+
+    process (child);
+  }
+
+  retval = TRUE;
+
+out:
+  if (obj)
+    xmlXPathFreeObject (obj);
+
+  xmlXPathFreeContext (ctx);
+
+  return retval;
+}
+
+int main (int argc, char *argv[]) 
+{
+  int retval = 1;
+  xmlDoc *doc;
+
+  if (argc != 3) {
+    g_printerr ("Usage: %s INPUT-FILE OUTPUT-FILE\n", argv[0]);
+    return 1;
+  }
+
+  pngcrush = g_find_program_in_path ("pngcrush");
+  if (pngcrush == NULL) {
+    g_printerr ("pngcrush not found in $PATH\n");
+    return 1;
+  }
+
+  doc = xmlReadFile (argv[1], "UTF-8", XML_PARSE_NONET);
+  if (doc == NULL)
+    goto out;
+
+  if (!transform (doc))
+    goto out;
+
+  if (xmlSaveFile (argv[2], doc) == -1)
+    goto out;
+
+  retval = 0;
+
+out:
+  if (doc)
+    xmlFreeDoc (doc);
+  g_free (pngcrush);
+
+  return retval;
+}