From 425fc7f3ee257b7aee9a481a04d368c4ccf57c4d Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Wed, 22 Feb 2023 12:19:06 -0700
Subject: [PATCH] [wasm] Add wasm shaper skeleton

---
 meson.build            |   2 +
 src/Makefile.sources   |   1 +
 src/harfbuzz-subset.cc |   1 +
 src/harfbuzz.cc        |   1 +
 src/hb-shaper-list.hh  |   5 +++
 src/hb-wasm-shape.cc   | 100 +++++++++++++++++++++++++++++++++++++++++
 src/meson.build        |   1 +
 7 files changed, 111 insertions(+)
 create mode 100644 src/hb-wasm-shape.cc

diff --git a/meson.build b/meson.build
index 6bf8d05da..95dbf2795 100644
--- a/meson.build
+++ b/meson.build
@@ -229,6 +229,8 @@ if chafa_dep.found()
   conf.set('HAVE_CHAFA', 1)
 endif
 
+conf.set('HAVE_WASM', 1)
+
 if graphite2_dep.found() or graphite_dep.found()
   conf.set('HAVE_GRAPHITE2', 1)
 endif
diff --git a/src/Makefile.sources b/src/Makefile.sources
index fd7c3b55e..4edea33c8 100644
--- a/src/Makefile.sources
+++ b/src/Makefile.sources
@@ -255,6 +255,7 @@ HB_BASE_sources = \
 	hb-unicode.hh \
 	hb-utf.hh \
 	hb-vector.hh \
+	hb-wasm-shape.cc \
 	hb-priority-queue.hh \
 	hb.hh \
 	$(NULL)
diff --git a/src/harfbuzz-subset.cc b/src/harfbuzz-subset.cc
index c0e23b3eb..743a3539d 100644
--- a/src/harfbuzz-subset.cc
+++ b/src/harfbuzz-subset.cc
@@ -60,3 +60,4 @@
 #include "hb-subset.cc"
 #include "hb-ucd.cc"
 #include "hb-unicode.cc"
+#include "hb-wasm-shape.cc"
diff --git a/src/harfbuzz.cc b/src/harfbuzz.cc
index d7e8a93f3..5b8196126 100644
--- a/src/harfbuzz.cc
+++ b/src/harfbuzz.cc
@@ -58,3 +58,4 @@
 #include "hb-ucd.cc"
 #include "hb-unicode.cc"
 #include "hb-uniscribe.cc"
+#include "hb-wasm-shape.cc"
diff --git a/src/hb-shaper-list.hh b/src/hb-shaper-list.hh
index 4158b7094..f079caf4d 100644
--- a/src/hb-shaper-list.hh
+++ b/src/hb-shaper-list.hh
@@ -33,6 +33,11 @@
 
 /* v--- Add new shapers in the right place here. */
 
+#ifdef HAVE_WASM
+/* Only picks up fonts that have a "Wasm" table. */
+HB_SHAPER_IMPLEMENT (wasm)
+#endif
+
 #ifdef HAVE_GRAPHITE2
 /* Only picks up fonts that have a "Silf" table. */
 HB_SHAPER_IMPLEMENT (graphite2)
diff --git a/src/hb-wasm-shape.cc b/src/hb-wasm-shape.cc
new file mode 100644
index 000000000..e67b880dc
--- /dev/null
+++ b/src/hb-wasm-shape.cc
@@ -0,0 +1,100 @@
+/*
+ * Copyright © 2011  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * 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.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#include "hb-shaper-impl.hh"
+
+#ifdef HAVE_WASM
+
+/*
+ * shaper face data
+ */
+
+#define HB_WASM_TAG_WASM HB_TAG('W','a','s','m')
+
+struct hb_wasm_face_data_t {
+  hb_blob_t *blob;
+};
+
+hb_wasm_face_data_t *
+_hb_wasm_shaper_face_data_create (hb_face_t *face)
+{
+  hb_blob_t *wasm_blob = hb_face_reference_table (face, HB_WASM_TAG_WASM);
+  if (!hb_blob_get_length (wasm_blob))
+  {
+    hb_blob_destroy (wasm_blob);
+    return nullptr;
+  }
+
+  hb_wasm_face_data_t *data = (hb_wasm_face_data_t *) hb_calloc (1, sizeof (hb_wasm_face_data_t));
+  if (unlikely (!data))
+    return nullptr;
+
+  data->blob = wasm_blob;
+
+  return data;
+}
+
+void
+_hb_wasm_shaper_face_data_destroy (hb_wasm_face_data_t *data)
+{
+  hb_blob_destroy (data->blob);
+  hb_free (data);
+}
+
+
+/*
+ * shaper font data
+ */
+
+struct hb_wasm_font_data_t {};
+
+hb_wasm_font_data_t *
+_hb_wasm_shaper_font_data_create (hb_font_t *font HB_UNUSED)
+{
+  return (hb_wasm_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
+}
+
+void
+_hb_wasm_shaper_font_data_destroy (hb_wasm_font_data_t *data HB_UNUSED)
+{
+}
+
+
+/*
+ * shaper
+ */
+
+hb_bool_t
+_hb_wasm_shape (hb_shape_plan_t    *shape_plan,
+		hb_font_t          *font,
+		hb_buffer_t        *buffer,
+		const hb_feature_t *features,
+		unsigned int        num_features)
+{
+  return false;
+}
+
+#endif
diff --git a/src/meson.build b/src/meson.build
index 30b99cf34..263677f84 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -256,6 +256,7 @@ hb_base_sources = files(
   'hb-unicode.hh',
   'hb-utf.hh',
   'hb-vector.hh',
+  'hb-wasm-shape.cc',
   'hb.hh',
 )