gfx/harfbuzz/src/hb-wasm-shape.cc

   1 /*
   2  * Copyright © 2011  Google, Inc.
   3  *
   4  *  This is part of HarfBuzz, a text shaping library.
   5  *
   6  * Permission is hereby granted, without written agreement and without
   7  * license or royalty fees, to use, copy, modify, and distribute this
   8  * software and its documentation for any purpose, provided that the
   9  * above copyright notice and the following two paragraphs appear in
  10  * all copies of this software.
  11  *
  12  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16  * DAMAGE.
  17  *
  18  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  21  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23  *
  24  * Google Author(s): Behdad Esfahbod
  25  */
  26
  27 #undef HB_DEBUG_WASM
  28 #define HB_DEBUG_WASM 1
  29
  30 #include "hb-shaper-impl.hh"
  31
  32 #ifdef HAVE_WASM
  33
  34 /* Compile wasm-micro-runtime with:
  35  *
  36  * $ cmake -DWAMR_BUILD_MULTI_MODULE=1 -DWAMR_BUILD_REF_TYPES=1 -DWAMR_BUILD_FAST_JIT=1
  37  * $ make
  38  *
  39  * If you manage to build a wasm shared module successfully and want to use it,
  40  * do the following:
  41  *
  42  *   - Add -DWAMR_BUILD_MULTI_MODULE=1 to your cmake build for wasm-micro-runtime,
  43  *
  44  *   - Remove the #define HB_WASM_NO_MODULES line below,
  45  *
  46  *   - Install your shared module with name ending in .wasm in
  47  *     $(prefix)/$(libdir)/harfbuzz/wasm/
  48  *
  49  *   - Build your font's wasm code importing the shared modules with the desired
  50  *     name. This can be done eg.: __attribute__((import_module("graphite2")))
  51  *     before each symbol in the shared-module's headers.
  52  *
  53  *   - Try shaping your font and hope for the best...
  54  *
  55  * I haven't been able to get this to work since emcc's support for shared libraries
  56  * requires support from the host that seems to be missing from wasm-micro-runtime?
  57  */
  58
  59 #include "hb-wasm-api.hh"
  60 #include "hb-wasm-api-list.hh"
  61
  62 #ifndef HB_WASM_NO_MODULES
  63 #define HB_WASM_NO_MODULES
  64 #endif
  65
  66
  67 #ifndef HB_WASM_NO_MODULES
  68 static bool HB_UNUSED
  69 _hb_wasm_module_reader (const char *module_name,
  70                        uint8_t **p_buffer, uint32_t *p_size)
  71 {
  72   char path[sizeof (HB_WASM_MODULE_DIR) + 64] = HB_WASM_MODULE_DIR "/";
  73   strncat (path, module_name, sizeof (path) - sizeof (HB_WASM_MODULE_DIR) - 16);
  74   strncat (path, ".wasm", 6);
  75
  76   auto *blob = hb_blob_create_from_file (path);
  77
  78   unsigned length;
  79   auto *data = hb_blob_get_data (blob, &length);
  80
  81   *p_buffer = (uint8_t *) hb_malloc (length);
  82
  83   if (length && !p_buffer)
  84     return false;
  85
  86   memcpy (*p_buffer, data, length);
  87   *p_size = length;
  88
  89   hb_blob_destroy (blob);
  90
  91   return true;
  92 }
  93
  94 static void HB_UNUSED
  95 _hb_wasm_module_destroyer (uint8_t *buffer, uint32_t size)
  96 {
  97   hb_free (buffer);
  98 }
  99 #endif
 100
 101 /*
 102  * shaper face data
 103  */
 104
 105 #define HB_WASM_TAG_WASM HB_TAG('W','a','s','m')
 106
 107 struct hb_wasm_shape_plan_t {
 108   wasm_module_inst_t module_inst;
 109   wasm_exec_env_t exec_env;
 110   ptr_d(void, wasm_shape_plan);
 111 };
 112
 113 struct hb_wasm_face_data_t {
 114   hb_blob_t *wasm_blob;
 115   wasm_module_t wasm_module;
 116   mutable hb_atomic_ptr_t<hb_wasm_shape_plan_t> plan;
 117 };
 118
 119 static bool
 120 _hb_wasm_init ()
 121 {
 122   /* XXX
 123    *
 124    * Umm. Make this threadsafe. How?!
 125    * It's clunky that we can't allocate a static mutex.
 126    * So we have to first allocate one on the heap atomically...
 127    *
 128    * Do we also need to lock around module creation?
 129    *
 130    * Also, wasm-micro-runtime uses a singleton instance. So if
 131    * another library or client uses it, all bets are off. :-(
 132    * If nothing else, around HB_REF2OBJ().
 133    */
 134
 135   static bool initialized;
 136   if (initialized)
 137     return true;
 138
 139   RuntimeInitArgs init_args;
 140   hb_memset (&init_args, 0, sizeof (RuntimeInitArgs));
 141
 142   init_args.mem_alloc_type = Alloc_With_Allocator;
 143   init_args.mem_alloc_option.allocator.malloc_func = (void *) hb_malloc;
 144   init_args.mem_alloc_option.allocator.realloc_func = (void *) hb_realloc;
 145   init_args.mem_alloc_option.allocator.free_func = (void *) hb_free;
 146
 147   // Native symbols need below registration phase
 148   init_args.n_native_symbols = ARRAY_LENGTH (_hb_wasm_native_symbols);
 149   init_args.native_module_name = "env";
 150   init_args.native_symbols = _hb_wasm_native_symbols;
 151
 152   if (unlikely (!wasm_runtime_full_init (&init_args)))
 153   {
 154     DEBUG_MSG (WASM, nullptr, "Init runtime environment failed.");
 155     return false;
 156   }
 157
 158 #ifndef HB_WASM_NO_MODULES
 159   wasm_runtime_set_module_reader (_hb_wasm_module_reader,
 160                                   _hb_wasm_module_destroyer);
 161 #endif
 162
 163   initialized = true;
 164   return true;
 165 }
 166
 167 hb_wasm_face_data_t *
 168 _hb_wasm_shaper_face_data_create (hb_face_t *face)
 169 {
 170   char error[128];
 171   hb_wasm_face_data_t *data = nullptr;
 172   hb_blob_t *wasm_blob = nullptr;
 173   wasm_module_t wasm_module = nullptr;
 174
 175   wasm_blob = hb_face_reference_table (face, HB_WASM_TAG_WASM);
 176   unsigned length = hb_blob_get_length (wasm_blob);
 177   if (!length)
 178     goto fail;
 179
 180   if (!_hb_wasm_init ())
 181     goto fail;
 182
 183   wasm_module = wasm_runtime_load ((uint8_t *) hb_blob_get_data_writable (wasm_blob, nullptr),
 184                                    length, error, sizeof (error));
 185   if (unlikely (!wasm_module))
 186   {
 187     DEBUG_MSG (WASM, nullptr, "Load wasm module failed: %s", error);
 188     goto fail;
 189   }
 190
 191   data = (hb_wasm_face_data_t *) hb_calloc (1, sizeof (hb_wasm_face_data_t));
 192   if (unlikely (!data))
 193     goto fail;
 194
 195   data->wasm_blob = wasm_blob;
 196   data->wasm_module = wasm_module;
 197
 198   return data;
 199
 200 fail:
 201   if (wasm_module)
 202       wasm_runtime_unload (wasm_module);
 203   hb_blob_destroy (wasm_blob);
 204   hb_free (data);
 205   return nullptr;
 206 }
 207
 208 static hb_wasm_shape_plan_t *
 209 acquire_shape_plan (hb_face_t *face,
 210                     const hb_wasm_face_data_t *face_data)
 211 {
 212   char error[128];
 213
 214   /* Fetch cached one if available. */
 215   hb_wasm_shape_plan_t *plan = face_data->plan.get_acquire ();
 216   if (likely (plan && face_data->plan.cmpexch (plan, nullptr)))
 217     return plan;
 218
 219   plan = (hb_wasm_shape_plan_t *) hb_calloc (1, sizeof (hb_wasm_shape_plan_t));
 220
 221   wasm_module_inst_t module_inst = nullptr;
 222   wasm_exec_env_t exec_env = nullptr;
 223   wasm_function_inst_t func = nullptr;
 224
 225   constexpr uint32_t stack_size = 32 * 1024, heap_size = 2 * 1024 * 1024;
 226
 227   module_inst = plan->module_inst = wasm_runtime_instantiate (face_data->wasm_module,
 228                                                               stack_size, heap_size,
 229                                                               error, sizeof (error));
 230   if (unlikely (!module_inst))
 231   {
 232     DEBUG_MSG (WASM, face_data, "Create wasm module instance failed: %s", error);
 233     goto fail;
 234   }
 235
 236   exec_env = plan->exec_env = wasm_runtime_create_exec_env (module_inst,
 237                                                             stack_size);
 238   if (unlikely (!exec_env)) {
 239     DEBUG_MSG (WASM, face_data, "Create wasm execution environment failed.");
 240     goto fail;
 241   }
 242
 243   func = wasm_runtime_lookup_function (module_inst, "shape_plan_create", nullptr);
 244   if (func)
 245   {
 246     wasm_val_t results[1];
 247     wasm_val_t arguments[1];
 248
 249     HB_OBJ2REF (face);
 250     if (unlikely (!faceref))
 251     {
 252       DEBUG_MSG (WASM, face_data, "Failed to register face object.");
 253       goto fail;
 254     }
 255
 256     results[0].kind = WASM_I32;
 257     arguments[0].kind = WASM_I32;
 258     arguments[0].of.i32 = faceref;
 259     bool ret = wasm_runtime_call_wasm_a (exec_env, func,
 260                                          ARRAY_LENGTH (results), results,
 261                                          ARRAY_LENGTH (arguments), arguments);
 262
 263     if (unlikely (!ret))
 264     {
 265       DEBUG_MSG (WASM, module_inst, "Calling shape_plan_create() failed: %s",
 266                  wasm_runtime_get_exception (module_inst));
 267       goto fail;
 268     }
 269     plan->wasm_shape_planptr = results[0].of.i32;
 270   }
 271
 272   return plan;
 273
 274 fail:
 275
 276   if (exec_env)
 277     wasm_runtime_destroy_exec_env (exec_env);
 278   if (module_inst)
 279     wasm_runtime_deinstantiate (module_inst);
 280   hb_free (plan);
 281   return nullptr;
 282 }
 283
 284 static void
 285 release_shape_plan (const hb_wasm_face_data_t *face_data,
 286                     hb_wasm_shape_plan_t *plan,
 287                     bool cache = false)
 288 {
 289   if (cache && face_data->plan.cmpexch (nullptr, plan))
 290     return;
 291
 292   auto *module_inst = plan->module_inst;
 293   auto *exec_env = plan->exec_env;
 294
 295   /* Is there even any point to having a shape_plan_destroy function
 296    * and calling it? */
 297   if (plan->wasm_shape_planptr)
 298   {
 299
 300     auto *func = wasm_runtime_lookup_function (module_inst, "shape_plan_destroy", nullptr);
 301     if (func)
 302     {
 303       wasm_val_t arguments[1];
 304
 305       arguments[0].kind = WASM_I32;
 306       arguments[0].of.i32 = plan->wasm_shape_planptr;
 307       bool ret = wasm_runtime_call_wasm_a (exec_env, func,
 308                                            0, nullptr,
 309                                            ARRAY_LENGTH (arguments), arguments);
 310
 311       if (unlikely (!ret))
 312       {
 313         DEBUG_MSG (WASM, module_inst, "Calling shape_plan_destroy() failed: %s",
 314                    wasm_runtime_get_exception (module_inst));
 315       }
 316     }
 317   }
 318
 319   wasm_runtime_destroy_exec_env (exec_env);
 320   wasm_runtime_deinstantiate (module_inst);
 321   hb_free (plan);
 322 }
 323
 324 void
 325 _hb_wasm_shaper_face_data_destroy (hb_wasm_face_data_t *data)
 326 {
 327   if (data->plan.get_relaxed ())
 328     release_shape_plan (data, data->plan);
 329   wasm_runtime_unload (data->wasm_module);
 330   hb_blob_destroy (data->wasm_blob);
 331   hb_free (data);
 332 }
 333
 334
 335 /*
 336  * shaper font data
 337  */
 338
 339 struct hb_wasm_font_data_t {};
 340
 341 hb_wasm_font_data_t *
 342 _hb_wasm_shaper_font_data_create (hb_font_t *font HB_UNUSED)
 343 {
 344   return (hb_wasm_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
 345 }
 346
 347 void
 348 _hb_wasm_shaper_font_data_destroy (hb_wasm_font_data_t *data HB_UNUSED)
 349 {
 350 }
 351
 352
 353 /*
 354  * shaper
 355  */
 356
 357 hb_bool_t
 358 _hb_wasm_shape (hb_shape_plan_t    *shape_plan,
 359                 hb_font_t          *font,
 360                 hb_buffer_t        *buffer,
 361                 const hb_feature_t *features,
 362                 unsigned int        num_features)
 363 {
 364   if (unlikely (buffer->in_error ()))
 365     return false;
 366
 367   bool ret = true;
 368   hb_face_t *face = font->face;
 369   const hb_wasm_face_data_t *face_data = face->data.wasm;
 370
 371   bool retried = false;
 372   if (0)
 373   {
 374 retry:
 375     DEBUG_MSG (WASM, font, "Retrying...");
 376   }
 377
 378   wasm_function_inst_t func = nullptr;
 379
 380   hb_wasm_shape_plan_t *plan = acquire_shape_plan (face, face_data);
 381   if (unlikely (!plan))
 382   {
 383     DEBUG_MSG (WASM, face_data, "Acquiring shape-plan failed.");
 384     return false;
 385   }
 386
 387   auto *module_inst = plan->module_inst;
 388   auto *exec_env = plan->exec_env;
 389
 390   HB_OBJ2REF (font);
 391   HB_OBJ2REF (buffer);
 392   if (unlikely (!fontref || !bufferref))
 393   {
 394     DEBUG_MSG (WASM, module_inst, "Failed to register objects.");
 395     goto fail;
 396   }
 397
 398   func = wasm_runtime_lookup_function (module_inst, "shape", nullptr);
 399   if (unlikely (!func))
 400   {
 401     DEBUG_MSG (WASM, module_inst, "Shape function not found.");
 402     goto fail;
 403   }
 404
 405   wasm_val_t results[1];
 406   wasm_val_t arguments[5];
 407
 408   results[0].kind = WASM_I32;
 409   arguments[0].kind = WASM_I32;
 410   arguments[0].of.i32 = plan->wasm_shape_planptr;
 411   arguments[1].kind = WASM_I32;
 412   arguments[1].of.i32 = fontref;
 413   arguments[2].kind = WASM_I32;
 414   arguments[2].of.i32 = bufferref;
 415   arguments[3].kind = WASM_I32;
 416   arguments[3].of.i32 = num_features ? wasm_runtime_module_dup_data (module_inst,
 417                                                                      (const char *) features,
 418                                                                      num_features * sizeof (features[0])) : 0;
 419   arguments[4].kind = WASM_I32;
 420   arguments[4].of.i32 = num_features;
 421
 422   ret = wasm_runtime_call_wasm_a (exec_env, func,
 423                                   ARRAY_LENGTH (results), results,
 424                                   ARRAY_LENGTH (arguments), arguments);
 425
 426   if (num_features)
 427     wasm_runtime_module_free (module_inst, arguments[2].of.i32);
 428
 429   if (unlikely (!ret || !results[0].of.i32))
 430   {
 431     DEBUG_MSG (WASM, module_inst, "Calling shape() failed: %s",
 432                wasm_runtime_get_exception (module_inst));
 433     if (!buffer->ensure_unicode ())
 434     {
 435       DEBUG_MSG (WASM, font, "Shape failed but buffer is not in Unicode; failing...");
 436       goto fail;
 437     }
 438     if (retried)
 439     {
 440       DEBUG_MSG (WASM, font, "Giving up...");
 441       goto fail;
 442     }
 443     buffer->successful = true;
 444     retried = true;
 445     release_shape_plan (face_data, plan);
 446     plan = nullptr;
 447     goto retry;
 448   }
 449
 450   /* TODO Regularize clusters according to direction & cluster level,
 451    * such that client doesn't crash with unmet expectations. */
 452
 453   if (!results[0].of.i32)
 454   {
 455 fail:
 456     ret = false;
 457   }
 458
 459   release_shape_plan (face_data, plan, ret);
 460
 461   if (ret)
 462   {
 463     buffer->clear_glyph_flags ();
 464     buffer->unsafe_to_break ();
 465   }
 466
 467   return ret;
 468 }
 469
 470 #endif