[config] Add HB_NO_OT_SHAPE / HB_NO_OT

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

CONFIG.md

@@ -86,6 +86,20 @@ In that case, or if you otherwise provide those functions by calling
 without loss of functionality by defining `HB_NO_OT_FONT`.
 
 
+## Shapers
+
+Most HarfBuzz clients use it for the main shaper, called "ot".  However, it
+is legitimate to want to compile HarfBuzz with only another backend, eg.
+CoreText, for example for an iOS app.  For that, you want `HB_NO_OT_SHAPE`,
+or more generally `HB_NO_OT`.
+
+This is very rarely what you need.  Make sure you understand exactly what you
+are doing.
+
+Defining `HB_NO_FALLBACK_SHAPE` however is pretty harmless.  That removes the
+(unused) "fallback" shaper.
+
+
 ## Thread-safety
 
 By default HarfBuzz builds as a thread-safe library.  The exception is that

src/gen-indic-table.py

@@ -98,6 +98,10 @@ for h in headers:
 		print (" * %s" % (l.strip()))
 print (" */")
 print ()
+print ('#include "hb.hh"')
+print ()
+print ('#ifndef HB_NO_OT_SHAPE')
+print ()
 print ('#include "hb-ot-shape-complex-indic.hh"')
 print ()
 
@@ -251,6 +255,8 @@ for i in range (2):
 		print ("#undef %s_%s" %
 			(what_short[i], short[i][v]))
 print ()
+print ()
+print ('#endif')
 print ("/* == End of generated table == */")
 
 # Maintain at least 30% occupancy in the table */

src/gen-use-table.py

@@ -419,6 +419,10 @@ for h in headers:
 		print (" * %s" % (l.strip()))
 print (" */")
 print ()
+print ('#include "hb.hh"')
+print ()
+print ('#ifndef HB_NO_OT_SHAPE')
+print ()
 print ('#include "hb-ot-shape-complex-use.hh"')
 print ()
 
@@ -533,6 +537,8 @@ for k,v in sorted(use_positions.items()):
 		tag = k + suf
 		print ("#undef %s" % tag)
 print ()
+print ()
+print ('#endif')
 print ("/* == End of generated table == */")
 
 # Maintain at least 50% occupancy in the table */

src/gen-vowel-constraints.py

@@ -157,6 +157,11 @@ print (' *')
 for line in scripts_header:
 	print (' * %s' % line.strip ())
 print (' */')
+
+print ()
+print ('#include "hb.hh"')
+print ()
+print ('#ifndef HB_NO_OT_SHAPE')
 print ()
 print ('#include "hb-ot-shape-complex-vowel-constraints.hh"')
 print ()
@@ -223,4 +228,6 @@ print ('  }')
 print ('}')
 
 print ()
+print ()
+print ('#endif')
 print ('/* == End of generated functions == */')

src/hb-config.hh

@@ -121,6 +121,10 @@
 #define HB_NO_OT_NAME_LANGUAGE
 #endif
 
+#ifdef HB_NO_OT
+#define HB_NO_OT_SHAPE
+#endif
+
 #ifdef HB_NO_OT_SHAPE_FALLBACK
 #define HB_NO_OT_SHAPE_COMPLEX_ARABIC_FALLBACK
 #define HB_NO_OT_SHAPE_COMPLEX_HEBREW_FALLBACK

src/hb-ot-shape-complex-arabic.cc

@@ -25,6 +25,9 @@
  */
 
 #include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-arabic.hh"
 #include "hb-ot-shape.hh"
 
@@ -710,3 +713,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-default.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex.hh"
 
 
@@ -44,3 +48,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_default =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-hangul.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex.hh"
 
 
@@ -430,3 +434,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hangul =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-hebrew.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex.hh"
 
 
@@ -176,3 +180,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hebrew =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-indic-table.cc

@@ -14,6 +14,10 @@
  * # Date: 2018-07-30, 19:40:00 GMT [KW]
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-indic.hh"
 
 #pragma GCC diagnostic push
@@ -487,4 +491,6 @@ hb_indic_get_categories (hb_codepoint_t u)
 #undef IMC_TR
 #undef IMC_VOL
 
+
+#endif
 /* == End of generated table == */

src/hb-ot-shape-complex-indic.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-indic.hh"
 #include "hb-ot-shape-complex-vowel-constraints.hh"
 #include "hb-ot-layout.hh"
@@ -1648,3 +1652,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-khmer.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-khmer.hh"
 #include "hb-ot-layout.hh"
 
@@ -502,3 +506,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_khmer =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-myanmar.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-myanmar.hh"
 
 
@@ -415,3 +419,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_myanmar_zawgyi =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
   false, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-thai.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex.hh"
 
 
@@ -385,3 +389,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_thai =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   false,/* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-use-table.cc

@@ -15,6 +15,10 @@
  * UnicodeData.txt does not have a header.
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-use.hh"
 
 #pragma GCC diagnostic push
@@ -851,4 +855,6 @@ hb_use_get_category (hb_codepoint_t u)
 #undef VMPst
 #undef VMAbv
 
+
+#endif
 /* == End of generated table == */

src/hb-ot-shape-complex-use.cc

@@ -26,6 +26,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-use.hh"
 #include "hb-ot-shape-complex-arabic.hh"
 #include "hb-ot-shape-complex-vowel-constraints.hh"
@@ -643,3 +647,6 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_use =
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
   false, /* fallback_position */
 };
+
+
+#endif

src/hb-ot-shape-complex-vowel-constraints.cc

@@ -13,6 +13,10 @@
  * # Date: 2019-01-28, 22:16:47 GMT
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-complex-vowel-constraints.hh"
 
 static void
@@ -440,4 +444,6 @@ _hb_preprocess_text_vowel_constraints (const hb_ot_shape_plan_t *plan HB_UNUSED,
   }
 }
 
+
+#endif
 /* == End of generated functions == */

src/hb-ot-shape-fallback.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-fallback.hh"
 #include "hb-kern.hh"
 
@@ -587,3 +591,6 @@ _hb_ot_shape_fallback_spaces (const hb_ot_shape_plan_t *plan HB_UNUSED,
       }
     }
 }
+
+
+#endif

src/hb-ot-shape-normalize.cc

@@ -24,6 +24,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-ot-shape-normalize.hh"
 #include "hb-ot-shape-complex.hh"
 #include "hb-ot-shape.hh"
@@ -469,3 +473,6 @@ _hb_ot_shape_normalize (const hb_ot_shape_plan_t *plan,
     buffer->swap_buffers ();
   }
 }
+
+
+#endif

src/hb-ot-shape.cc

@@ -26,6 +26,10 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
 #include "hb-shaper-impl.hh"
 
 #include "hb-ot-shape.hh"
@@ -1146,3 +1150,6 @@ hb_ot_shape_glyphs_closure (hb_font_t          *font,
 
   hb_shape_plan_destroy (shape_plan);
 }
+
+
+#endif

src/hb-shape-plan.cc

@@ -79,7 +79,9 @@ hb_shape_plan_key_t::init (bool                           copy,
   }
   this->shaper_func = nullptr;
   this->shaper_name = nullptr;
+#ifndef HB_NO_OT_SHAPE
   this->ot.init (face, coords, num_coords);
+#endif
 
   /*
    * Choose shaper.
@@ -148,7 +150,9 @@ hb_shape_plan_key_t::equal (const hb_shape_plan_key_t *other)
 {
   return hb_segment_properties_equal (&this->props, &other->props) &&
 	 this->user_features_match (other) &&
+#ifndef HB_NO_OT_SHAPE
 	 this->ot.equal (&other->ot) &&
+#endif
 	 this->shaper_func == other->shaper_func;
 }
 
@@ -224,12 +228,16 @@ hb_shape_plan_create2 (hb_face_t                     *face,
 				       num_coords,
 				       shaper_list)))
     goto bail2;
+#ifndef HB_NO_OT_SHAPE
   if (unlikely (!shape_plan->ot.init0 (face, &shape_plan->key)))
     goto bail3;
+#endif
 
   return shape_plan;
 
+#ifndef HB_NO_OT_SHAPE
 bail3:
+#endif
   shape_plan->key.free ();
 bail2:
   free (shape_plan);
@@ -281,7 +289,9 @@ hb_shape_plan_destroy (hb_shape_plan_t *shape_plan)
 {
   if (!hb_object_destroy (shape_plan)) return;
 
+#ifndef HB_NO_OT_SHAPE
   shape_plan->ot.fini ();
+#endif
   shape_plan->key.free ();
   free (shape_plan);
 }

src/hb-shape-plan.hh

@@ -39,7 +39,9 @@ struct hb_shape_plan_key_t
   const hb_feature_t      *user_features;
   unsigned int             num_user_features;
 
+#ifndef HB_NO_OT_SHAPE
   hb_ot_shape_plan_key_t   ot;
+#endif
 
   hb_shape_func_t         *shaper_func;
   const char              *shaper_name;
@@ -65,7 +67,9 @@ struct hb_shape_plan_t
   hb_object_header_t header;
   hb_face_t *face_unsafe; /* We don't carry a reference to face. */
   hb_shape_plan_key_t key;
+#ifndef HB_NO_OT_SHAPE
   hb_ot_shape_plan_t ot;
+#endif
 };
 
 

src/hb-shaper-list.hh

@@ -35,7 +35,9 @@
 HB_SHAPER_IMPLEMENT (graphite2)
 #endif
 
+#ifndef HB_NO_OT_SHAPE
 HB_SHAPER_IMPLEMENT (ot) /* <--- This is our main OpenType shaper. */
+#endif
 
 #ifdef HAVE_UNISCRIBE
 HB_SHAPER_IMPLEMENT (uniscribe)