[autofit] Don't depend on 'hb-ft'.

The circular dependency is still there, but at least we no longer depend on
the HarfBuzz API that is only present if HarfBuzz has been built with
FreeType support, making the bootstrapping a bit easier.

* src/autofit/ft-hb.c, src/autofit/ft-hb.h: New files, providing
`_hb_ft_font_create`, which is more or less a verbatim copy of the
corresponding HarfBuzz code from file `hb-ft.cc`.

* src/autofit/afglobal.c (af_face_globals_new): Use it.
* src/autofit/afshaper.h: Don't include `hb-ft.h` but `ft-hb.h`.
* src/autofit/autofit.c: Include `ft-hb.c`.

* LICENSE.TXT: Updated.

LICENSE.TXT

@@ -35,6 +35,10 @@ in earlier FreeType versions.
 The gzip  module uses the  zlib license (see  `src/gzip/zlib.h`) which
 too is compatible to the above two licenses.
 
+The files `src/autofit/ft-hb.c` and `src/autofit/ft-hb.h` contain code
+taken almost  verbatim from the  HarfBuzz file `hb-ft.cc`,  which uses
+the 'Old MIT' license, compatible to the above two licenses.
+
 The  MD5 checksum  support  (only used  for  debugging in  development
 builds) is in the public domain.
 

src/autofit/afglobal.c

@@ -356,7 +356,7 @@
     globals->scale_down_factor         = 0;
 
 #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
-    globals->hb_font = hb_ft_font_create( face, NULL );
+    globals->hb_font = _hb_ft_font_create( face, NULL );
     globals->hb_buf  = hb_buffer_create();
 #endif
 

src/autofit/afshaper.h

@@ -27,7 +27,7 @@
 
 #include <hb.h>
 #include <hb-ot.h>
-#include <hb-ft.h>
+#include "ft-hb.h"
 
 #endif
 

src/autofit/autofit.c

@@ -18,6 +18,7 @@
 
 #define FT_MAKE_OPTION_SINGLE_OBJECT
 
+#include "ft-hb.c"
 #include "afblue.c"
 #include "afcjk.c"
 #include "afdummy.c"

src/autofit/ft-hb.c

@@ -0,0 +1,106 @@
+/*
+ * Copyright © 2009, 2023  Red Hat, Inc.
+ * Copyright © 2015  Google, Inc.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Red Hat Author(s): Behdad Esfahbod, Matthias Clasen
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include <freetype/freetype.h>
+#include <freetype/tttables.h>
+
+#ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
+
+#include "ft-hb.h"
+
+/* The following three functions are a more or less verbatim
+ * copy of corresponding HarfBuzz code from hb-ft.cc
+ */
+
+static hb_blob_t *
+_hb_ft_reference_table (hb_face_t *face, hb_tag_t tag, void *user_data)
+{
+  FT_Face ft_face = (FT_Face) user_data;
+  FT_Byte *buffer;
+  FT_ULong  length = 0;
+  FT_Error error;
+
+  /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */
+
+  error = FT_Load_Sfnt_Table (ft_face, tag, 0, NULL, &length);
+  if (error)
+    return NULL;
+
+  buffer = (FT_Byte *) malloc (length);
+  if (!buffer)
+    return NULL;
+
+  error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
+  if (error)
+  {
+    free (buffer);
+    return NULL;
+  }
+
+  return hb_blob_create ((const char *) buffer, length,
+                         HB_MEMORY_MODE_WRITABLE,
+                         buffer, free);
+}
+
+static hb_face_t *
+_hb_ft_face_create (FT_Face           ft_face,
+                    hb_destroy_func_t destroy)
+{
+  hb_face_t *face;
+
+  if (!ft_face->stream->read) {
+    hb_blob_t *blob;
+
+    blob = hb_blob_create ((const char *) ft_face->stream->base,
+                           (unsigned int) ft_face->stream->size,
+                           HB_MEMORY_MODE_READONLY,
+                           ft_face, destroy);
+    face = hb_face_create (blob, ft_face->face_index);
+    hb_blob_destroy (blob);
+  } else {
+    face = hb_face_create_for_tables (_hb_ft_reference_table, ft_face, destroy);
+  }
+
+  hb_face_set_index (face, ft_face->face_index);
+  hb_face_set_upem (face, ft_face->units_per_EM);
+
+  return face;
+}
+
+hb_font_t *
+_hb_ft_font_create (FT_Face           ft_face,
+                    hb_destroy_func_t destroy)
+{
+  hb_font_t *font;
+  hb_face_t *face;
+
+  face = _hb_ft_face_create (ft_face, destroy);
+  font = hb_font_create (face);
+  hb_face_destroy (face);
+  return font;
+}
+
+#endif

src/autofit/ft-hb.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright © 2009, 2023  Red Hat, Inc.
+ * Copyright © 2015  Google, Inc.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Red Hat Author(s): Behdad Esfahbod, Matthias Clasen
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef FT_HB_H
+#define FT_HB_H
+
+#include <hb.h>
+
+hb_font_t * _hb_ft_font_create (FT_Face           ft_face,
+                                hb_destroy_func_t destroy);
+
+#endif