mapi: Add a generic C dispatcher.

The idea is to have an API generate a header using mapi_abi.py.  The API
can then use the header to build a dispatcher.

1 files changed, 180 insertions, 0 deletions

diff --git a/src/mapi/mapi/stub.c b/src/mapi/mapi/stub.c
new file mode 100644
index 0000000000..8ceaec3132
--- /dev/null
+++ b/src/mapi/mapi/stub.c
@@ -0,0 +1,180 @@
+/*
+ * Mesa 3-D graphics library
+ * Version:  7.9
+ *
+ * Copyright (C) 2010 LunarG Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Chia-I Wu <olv@lunarg.com>
+ */
+
+#include <stdlib.h>
+#include <stddef.h> /* for offsetof */
+#include <string.h>
+#include <assert.h>
+
+#include "u_current.h"
+#include "u_thread.h"
+#include "entry.h"
+#include "stub.h"
+#include "table.h"
+
+#define MAPI_TABLE_FIRST_DYNAMIC \
+   (offsetof(struct mapi_table, dynamic0) / sizeof(mapi_func))
+#define MAPI_TABLE_NUM_DYNAMIC \
+   ((offsetof(struct mapi_table, last) - \
+     offsetof(struct mapi_table, dynamic0)) / sizeof(mapi_func))
+#define ARRAY_SIZE(x) (sizeof(x)/sizeof((x)[0]))
+
+/*
+ * This will define public_string_pool, public_sorted_indices, and
+ * public_stubs.
+ */
+#define MAPI_TMP_PUBLIC_STUBS
+#include "mapi_tmp.h"
+
+static struct mapi_stub dynamic_stubs[MAPI_TABLE_NUM_DYNAMIC];
+static int num_dynamic_stubs;
+static int next_dynamic_slot = MAPI_TABLE_FIRST_DYNAMIC;
+
+void
+stub_init_once(void)
+{
+#ifdef PTHREADS
+   static pthread_once_t once = PTHREAD_ONCE_INIT;
+   pthread_once(&once, entry_patch_public);
+#else
+   static int first = 1;
+   if (first) {
+      first = 0;
+      entry_patch_public();
+   }
+#endif
+}
+
+static int
+stub_compare(const void *key, const void *elem)
+{
+   const char *name = (const char *) key;
+   const int *index = (const int *) elem;
+   const struct mapi_stub *stub;
+   const char *stub_name;
+
+   stub = &public_stubs[*index];
+   stub_name = &public_string_pool[(unsigned long) stub->name];
+
+   return strcmp(name, stub_name);
+}
+
+/**
+ * Return the public stub with the given name.
+ */
+const struct mapi_stub *
+stub_find_public(const char *name)
+{
+   const int *index;
+
+   index = (const int *) bsearch(name, public_sorted_indices,
+         ARRAY_SIZE(public_sorted_indices) - 1,
+         sizeof(public_sorted_indices[0]), stub_compare);
+
+   return (index) ? &public_stubs[*index] : NULL;
+}
+
+/**
+ * Add a dynamic stub.
+ */
+static struct mapi_stub *
+stub_add_dynamic(const char *name)
+{
+   struct mapi_stub *stub;
+   int idx;
+
+   idx = num_dynamic_stubs;
+   if (idx >= MAPI_TABLE_NUM_DYNAMIC)
+      return NULL;
+
+   stub = &dynamic_stubs[idx];
+
+   /* dispatch to mapi_table->last, which is always no-op */
+   stub->addr =
+      entry_generate(MAPI_TABLE_FIRST_DYNAMIC + MAPI_TABLE_NUM_DYNAMIC);
+   if (!stub->addr)
+      return NULL;
+
+   stub->name = (const void *) name;
+   /* to be fixed later */
+   stub->slot = -1;
+
+   num_dynamic_stubs = idx + 1;
+
+   return stub;
+}
+
+/**
+ * Return the dynamic stub with the given name.  If no such stub exists and
+ * generate is true, a new stub is generated.
+ */
+struct mapi_stub *
+stub_find_dynamic(const char *name, int generate)
+{
+   u_mutex_declare_static(dynamic_mutex);
+   struct mapi_stub *stub = NULL;
+   int count, i;
+   
+   u_mutex_lock(dynamic_mutex);
+
+   if (generate)
+      assert(!stub_find_public(name));
+
+   count = num_dynamic_stubs;
+   for (i = 0; i < count; i++) {
+      if (strcmp(name, (const char *) dynamic_stubs[i].name) == 0) {
+         stub = &dynamic_stubs[i];
+         break;
+      }
+   }
+
+   /* generate a dynamic stub */
+   if (generate && !stub)
+         stub = stub_add_dynamic(name);
+
+   u_mutex_unlock(dynamic_mutex);
+
+   return stub;
+}
+
+void
+stub_fix_dynamic(struct mapi_stub *stub, const struct mapi_stub *alias)
+{
+   int slot;
+
+   if (stub->slot >= 0)
+      return;
+
+   if (alias)
+      slot = alias->slot;
+   else
+      slot = next_dynamic_slot++;
+
+   entry_patch(stub->addr, slot);
+   stub->slot = slot;
+}