/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
 * GObject introspection: typelib validation, auxiliary functions
 * related to the binary typelib format
 *
 * Copyright (C) 2005 Matthias Clasen
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <stdlib.h>
#include <string.h>

#include <glib.h>

#include "config.h"
#include "gitypelib-internal.h"
#include "glib-compat.h"

typedef struct {
  GITypelib *typelib;
  GSList *context_stack;
} ValidateContext;

#define ALIGN_VALUE(this, boundary) \
  (( ((unsigned long)(this)) + (((unsigned long)(boundary)) -1)) & (~(((unsigned long)(boundary))-1)))

static void
push_context (ValidateContext *ctx, const char *name)
{
  ctx->context_stack = g_slist_prepend (ctx->context_stack, (char*)name);
}

static void
pop_context (ValidateContext *ctx)
{
  g_assert (ctx->context_stack != NULL);
  ctx->context_stack = g_slist_delete_link (ctx->context_stack,
					    ctx->context_stack);
}

static gboolean
validate_interface_blob (ValidateContext *ctx,
			 guint32        offset,
			 GError       **error);

static DirEntry *
get_dir_entry_checked (GITypelib *typelib,
		       guint16    index,
		       GError   **error)
{
  Header *header = (Header *)typelib->data;
  guint32 offset;

  if (index == 0 || index > header->n_entries)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Invalid directory index %d", index);
      return FALSE;
    }

  offset = header->directory + (index - 1) * header->entry_blob_size;

  if (typelib->len < offset + sizeof (DirEntry))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  return (DirEntry *)&typelib->data[offset];
}


static CommonBlob *
get_blob (GITypelib *typelib,
	  guint32   offset,
	  GError  **error)
{
  if (typelib->len < offset + sizeof (CommonBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }
  return (CommonBlob *)&typelib->data[offset];
}

static InterfaceTypeBlob *
get_type_blob (GITypelib *typelib,
	       SimpleTypeBlob *simple,
	       GError  **error)
{
  if (simple->offset == 0)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "Expected blob for type");
      return FALSE;
    }

  if (simple->flags.reserved == 0 && simple->flags.reserved2 == 0)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "Expected non-basic type but got %d",
		   simple->flags.tag);
      return FALSE;
    }

  return (InterfaceTypeBlob*) get_blob (typelib, simple->offset, error);
}

DirEntry *
g_typelib_get_dir_entry (GITypelib *typelib,
			  guint16    index)
{
  Header *header = (Header *)typelib->data;

  return (DirEntry *)&typelib->data[header->directory + (index - 1) * header->entry_blob_size];
}

static Section *
get_section_by_id (GITypelib   *typelib,
		   SectionType  section_type)
{
  Header *header = (Header *)typelib->data;
  Section *section;

  if (header->sections == 0)
    return NULL;

  for (section = (Section*)&typelib->data[header->sections];
       section->id != GI_SECTION_END;
       section++)
    {
      if (section->id == section_type)
	return section;
    }
  return NULL;
}

DirEntry *
g_typelib_get_dir_entry_by_name (GITypelib *typelib,
				 const char *name)
{
  Section *dirindex;
  gint i;
  const char *entry_name;
  DirEntry *entry;

  dirindex = get_section_by_id (typelib, GI_SECTION_DIRECTORY_INDEX);

  if (dirindex == NULL)
    {
      gint n_entries = ((Header *)typelib->data)->n_local_entries;
      for (i = 1; i <= n_entries; i++)
	{
	  entry = g_typelib_get_dir_entry (typelib, i);
	  entry_name = g_typelib_get_string (typelib, entry->name);
	  if (strcmp (name, entry_name) == 0)
	    return entry;
	}
      return NULL;
    }
  else
    {
      guint8 *hash = (guint8*) &typelib->data[dirindex->offset];
      guint16 index;

      index = _gi_typelib_hash_search (hash, name);
      entry = g_typelib_get_dir_entry (typelib, index + 1);
      entry_name = g_typelib_get_string (typelib, entry->name);
      if (strcmp (name, entry_name) == 0)
	return entry;
      return NULL;
    }
}

DirEntry *
g_typelib_get_dir_entry_by_gtype (GITypelib *typelib,
				  gboolean   fastpass,
				  GType      gtype)
{
  Header *header = (Header *)typelib->data;
  guint n_entries = header->n_local_entries;
  const char *gtype_name = g_type_name (gtype);
  DirEntry *entry;
  guint i;
  const char *c_prefix;

  /* There is a corner case regarding GdkRectangle.  GdkRectangle is a
     boxed type, but it is just an alias to boxed struct
     CairoRectangleInt.  Scanner automatically converts all references
     to GdkRectangle to CairoRectangleInt, so GdkRectangle does not
     appear in the typelibs at all, although user code might query it.
     So if we get such query, we also change it to lookup of
     CairoRectangleInt.
     https://bugzilla.gnome.org/show_bug.cgi?id=655423 */
  if (!fastpass && !strcmp (gtype_name, "GdkRectangle"))
    gtype_name = "CairoRectangleInt";

  /* Inside each typelib, we include the "C prefix" which acts as
   * a namespace mechanism.  For GtkTreeView, the C prefix is Gtk.
   * Given the assumption that GTypes for a library also use the
   * C prefix, we know we can skip examining a typelib if our
   * target type does not have this typelib's C prefix.
   *
   * However, not every class library necessarily conforms to this,
   * e.g. Clutter has Cogl inside it.  So, we split this into two
   * passes.  First we try a lookup, skipping things which don't
   * have the prefix.  If that fails then we try a global lookup,
   * ignoring the prefix.
   *
   * See http://bugzilla.gnome.org/show_bug.cgi?id=564016
   */
  c_prefix = g_typelib_get_string (typelib, header->c_prefix);
  if (fastpass && c_prefix != NULL)
    {
      if (g_ascii_strncasecmp (c_prefix, gtype_name, strlen (c_prefix)) != 0)
	return NULL;
    }

  for (i = 1; i <= n_entries; i++)
    {
      RegisteredTypeBlob *blob;
      const char *type;

      entry = g_typelib_get_dir_entry (typelib, i);
      if (!BLOB_IS_REGISTERED_TYPE (entry))
	continue;

      blob = (RegisteredTypeBlob *)(&typelib->data[entry->offset]);
      if (!blob->gtype_name)
	continue;

      type = g_typelib_get_string (typelib, blob->gtype_name);
      if (strcmp (type, gtype_name) == 0)
	return entry;
    }
  return NULL;
}

DirEntry *
g_typelib_get_dir_entry_by_error_domain (GITypelib *typelib,
					 GQuark     error_domain)
{
  Header *header = (Header *)typelib->data;
  guint n_entries = header->n_local_entries;
  const char *domain_string = g_quark_to_string (error_domain);
  DirEntry *entry;
  guint i;

  for (i = 1; i <= n_entries; i++)
    {
      EnumBlob *blob;
      const char *enum_domain_string;

      entry = g_typelib_get_dir_entry (typelib, i);
      if (entry->blob_type != BLOB_TYPE_ENUM)
	continue;

      blob = (EnumBlob *)(&typelib->data[entry->offset]);
      if (!blob->error_domain)
	continue;

      enum_domain_string = g_typelib_get_string (typelib, blob->error_domain);
      if (strcmp (domain_string, enum_domain_string) == 0)
	return entry;
    }
  return NULL;
}

void
g_typelib_check_sanity (void)
{
  /* Check that struct layout is as we expect */

  gboolean size_check_ok = TRUE;

#define CHECK_SIZE(s,n) \
  if (sizeof(s) != n) \
    { \
      g_printerr ("sizeof("#s") is expected to be %d but is %"G_GSIZE_FORMAT".\n", \
		  n, sizeof (s));					\
      size_check_ok = FALSE; \
    }

  /* When changing the size of a typelib structure, you are required to update
   * the hardcoded size here.  Do NOT change these to use sizeof(); these
   * should match whatever is defined in the text specification and serve as
   * a sanity check on structure modifications.
   *
   * Everything else in the code however should be using sizeof().
   */

  CHECK_SIZE (Header, 112);
  CHECK_SIZE (DirEntry, 12);
  CHECK_SIZE (SimpleTypeBlob, 4);
  CHECK_SIZE (ArgBlob, 16);
  CHECK_SIZE (SignatureBlob, 8);
  CHECK_SIZE (CommonBlob, 8);
  CHECK_SIZE (FunctionBlob, 20);
  CHECK_SIZE (CallbackBlob, 12);
  CHECK_SIZE (InterfaceTypeBlob, 4);
  CHECK_SIZE (ArrayTypeBlob, 8);
  CHECK_SIZE (ParamTypeBlob, 4);
  CHECK_SIZE (ErrorTypeBlob, 4);
  CHECK_SIZE (ValueBlob, 12);
  CHECK_SIZE (FieldBlob, 16);
  CHECK_SIZE (RegisteredTypeBlob, 16);
  CHECK_SIZE (StructBlob, 32);
  CHECK_SIZE (EnumBlob, 24);
  CHECK_SIZE (PropertyBlob, 16);
  CHECK_SIZE (SignalBlob, 16);
  CHECK_SIZE (VFuncBlob, 20);
  CHECK_SIZE (ObjectBlob, 60);
  CHECK_SIZE (InterfaceBlob, 40);
  CHECK_SIZE (ConstantBlob, 24);
  CHECK_SIZE (AttributeBlob, 12);
  CHECK_SIZE (UnionBlob, 40);
#undef CHECK_SIZE

  g_assert (size_check_ok);
}


static gboolean
is_aligned (guint32 offset)
{
  return offset == ALIGN_VALUE (offset, 4);
}

#define MAX_NAME_LEN 200

static const char *
get_string (GITypelib *typelib, guint32 offset, GError **error)
{
  if (typelib->len < offset)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "Buffer is too short while looking up name");
      return NULL;
    }

  return (const char*)&typelib->data[offset];
}

static const char *
get_string_nofail (GITypelib *typelib, guint32 offset)
{
  const char *ret = get_string (typelib, offset, NULL);
  g_assert (ret);
  return ret;
}

static gboolean
validate_name (GITypelib   *typelib,
	       const char *msg,
	       const guchar *data, guint32 offset,
	       GError **error)
{
  const char *name;

  name = get_string (typelib, offset, error);
  if (!name)
    return FALSE;

  if (!memchr (name, '\0', MAX_NAME_LEN))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The %s is too long: %s",
		   msg, name);
      return FALSE;
    }

  if (strspn (name, G_CSET_a_2_z G_CSET_A_2_Z G_CSET_DIGITS "-_") < strlen (name))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The %s contains invalid characters: '%s'",
		   msg, name);
      return FALSE;
    }

  return TRUE;
}

/* Fast path sanity check, operates on a memory blob */
static gboolean
validate_header_basic (const guint8   *memory,
		       gsize           len,
		       GError        **error)
{
  Header *header = (Header *)memory;

  if (len < sizeof (Header))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The specified typelib length %" G_GSIZE_FORMAT " is too short",
		   len);
      return FALSE;
    }

  if (strncmp (header->magic, G_IR_MAGIC, 16) != 0)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Invalid magic header");
      return FALSE;

    }

  if (header->major_version != 4)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Typelib version mismatch; expected 4, found %d",
		   header->major_version);
      return FALSE;

    }

  if (header->n_entries < header->n_local_entries)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Inconsistent entry counts");
      return FALSE;
    }

  if (header->size != len)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Typelib size %" G_GSIZE_FORMAT " does not match %" G_GSIZE_FORMAT,
		   (gsize) header->size, len);
      return FALSE;
    }

  /* This is a sanity check for a specific typelib; it
   * prevents us from loading an incompatible typelib.
   *
   * The hardcoded checks in g_typelib_check_sanity to
   * protect against inadvertent or buggy changes to the typelib format
   * itself.
   */

  if (header->entry_blob_size != sizeof (DirEntry) ||
      header->function_blob_size != sizeof (FunctionBlob) ||
      header->callback_blob_size != sizeof (CallbackBlob) ||
      header->signal_blob_size != sizeof (SignalBlob) ||
      header->vfunc_blob_size != sizeof (VFuncBlob) ||
      header->arg_blob_size != sizeof (ArgBlob) ||
      header->property_blob_size != sizeof (PropertyBlob) ||
      header->field_blob_size != sizeof (FieldBlob) ||
      header->value_blob_size != sizeof (ValueBlob) ||
      header->constant_blob_size != sizeof (ConstantBlob) ||
      header->attribute_blob_size != sizeof (AttributeBlob) ||
      header->signature_blob_size != sizeof (SignatureBlob) ||
      header->enum_blob_size != sizeof (EnumBlob) ||
      header->struct_blob_size != sizeof (StructBlob) ||
      header->object_blob_size != sizeof(ObjectBlob) ||
      header->interface_blob_size != sizeof (InterfaceBlob) ||
      header->union_blob_size != sizeof (UnionBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Blob size mismatch");
      return FALSE;
    }

  if (!is_aligned (header->directory))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Misaligned directory");
      return FALSE;
    }

  if (!is_aligned (header->attributes))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Misaligned attributes");
      return FALSE;
    }

  if (header->attributes == 0 && header->n_attributes > 0)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_HEADER,
		   "Wrong number of attributes");
      return FALSE;
    }

  return TRUE;
}

static gboolean
validate_header (ValidateContext  *ctx,
		 GError          **error)
{
  GITypelib *typelib = ctx->typelib;
  
  if (!validate_header_basic (typelib->data, typelib->len, error))
    return FALSE;

  {
    Header *header = (Header*)typelib->data;
    if (!validate_name (typelib, "namespace", typelib->data, header->namespace, error))
      return FALSE;
  }

  return TRUE;
}

static gboolean validate_type_blob (GITypelib     *typelib,
				    guint32        offset,
				    guint32        signature_offset,
				    gboolean       return_type,
				    GError       **error);

static gboolean
validate_array_type_blob (GITypelib     *typelib,
			  guint32        offset,
			  guint32        signature_offset,
			  gboolean       return_type,
			  GError       **error)
{
  /* FIXME validate length */

  if (!validate_type_blob (typelib,
			   offset + G_STRUCT_OFFSET (ArrayTypeBlob, type),
			   0, FALSE, error))
    return FALSE;

  return TRUE;
}

static gboolean
validate_iface_type_blob (GITypelib     *typelib,
			  guint32        offset,
			  guint32        signature_offset,
			  gboolean       return_type,
			  GError       **error)
{
  InterfaceTypeBlob *blob;
  InterfaceBlob *target;

  blob = (InterfaceTypeBlob*)&typelib->data[offset];

  target = (InterfaceBlob*) get_dir_entry_checked (typelib, blob->interface, error);

  if (!target)
    return FALSE;
  if (target->blob_type == 0) /* non-local */
    return TRUE;

  return TRUE;
}

static gboolean
validate_param_type_blob (GITypelib     *typelib,
			  guint32        offset,
			  guint32        signature_offset,
			  gboolean       return_type,
			  gint           n_params,
			  GError       **error)
{
  ParamTypeBlob *blob;
  gint i;

  blob = (ParamTypeBlob*)&typelib->data[offset];

  if (!blob->pointer)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Pointer type exected for tag %d", blob->tag);
      return FALSE;
    }

  if (blob->n_types != n_params)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Parameter type number mismatch");
      return FALSE;
    }

  for (i = 0; i < n_params; i++)
    {
      if (!validate_type_blob (typelib,
			       offset + sizeof (ParamTypeBlob) +
			       i * sizeof (SimpleTypeBlob),
			       0, FALSE, error))
	return FALSE;
    }

  return TRUE;
}

static gboolean
validate_error_type_blob (GITypelib     *typelib,
			  guint32        offset,
			  guint32        signature_offset,
			  gboolean       return_type,
			  GError       **error)
{
  ErrorTypeBlob *blob;

  blob = (ErrorTypeBlob*)&typelib->data[offset];

  if (!blob->pointer)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Pointer type exected for tag %d", blob->tag);
      return FALSE;
    }

  return TRUE;
}

static gboolean
validate_type_blob (GITypelib     *typelib,
		    guint32        offset,
		    guint32        signature_offset,
		    gboolean       return_type,
		    GError       **error)
{
  SimpleTypeBlob *simple;
  InterfaceTypeBlob *iface;

  simple = (SimpleTypeBlob *)&typelib->data[offset];

  if (simple->flags.reserved == 0 &&
      simple->flags.reserved2 == 0)
    {
      if (!G_TYPE_TAG_IS_BASIC(simple->flags.tag))
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Invalid non-basic tag %d in simple type", simple->flags.tag);
	  return FALSE;
	}

      if (simple->flags.tag >= GI_TYPE_TAG_UTF8 &&
	  simple->flags.tag != GI_TYPE_TAG_UNICHAR &&
	  !simple->flags.pointer)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Pointer type exected for tag %d", simple->flags.tag);
	  return FALSE;
	}

      return TRUE;
    }

  iface = (InterfaceTypeBlob*)&typelib->data[simple->offset];

  switch (iface->tag)
    {
    case GI_TYPE_TAG_ARRAY:
      if (!validate_array_type_blob (typelib, simple->offset,
				     signature_offset, return_type, error))
	return FALSE;
      break;
    case GI_TYPE_TAG_INTERFACE:
      if (!validate_iface_type_blob (typelib, simple->offset,
				     signature_offset, return_type, error))
	return FALSE;
      break;
    case GI_TYPE_TAG_GLIST:
    case GI_TYPE_TAG_GSLIST:
      if (!validate_param_type_blob (typelib, simple->offset,
				     signature_offset, return_type, 1, error))
	return FALSE;
      break;
    case GI_TYPE_TAG_GHASH:
      if (!validate_param_type_blob (typelib, simple->offset,
				     signature_offset, return_type, 2, error))
	return FALSE;
      break;
    case GI_TYPE_TAG_ERROR:
      if (!validate_error_type_blob (typelib, simple->offset,
				     signature_offset, return_type, error))
	return FALSE;
      break;
    default:
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong tag in complex type");
      return FALSE;
    }

  return TRUE;
}

static gboolean
validate_arg_blob (GITypelib     *typelib,
		   guint32        offset,
		   guint32        signature_offset,
		   GError       **error)
{
  ArgBlob *blob;

  if (typelib->len < offset + sizeof (ArgBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (ArgBlob*) &typelib->data[offset];

  if (!validate_name (typelib, "argument", typelib->data, blob->name, error))
    return FALSE;

  if (!validate_type_blob (typelib,
			   offset + G_STRUCT_OFFSET (ArgBlob, arg_type),
			   signature_offset, FALSE, error))
    return FALSE;

  return TRUE;
}

static SimpleTypeBlob *
return_type_from_signature (GITypelib *typelib,
			    guint32   offset,
			    GError  **error)
{
  SignatureBlob *blob;
  if (typelib->len < offset + sizeof (SignatureBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return NULL;
    }

  blob = (SignatureBlob*) &typelib->data[offset];
  if (blob->return_type.offset == 0)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "No return type found in signature");
      return NULL;
    }

  return (SimpleTypeBlob *)&typelib->data[offset + G_STRUCT_OFFSET (SignatureBlob, return_type)];
}

static gboolean
validate_signature_blob (GITypelib     *typelib,
			 guint32        offset,
			 GError       **error)
{
  SignatureBlob *blob;
  gint i;

  if (typelib->len < offset + sizeof (SignatureBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (SignatureBlob*) &typelib->data[offset];

  if (blob->return_type.offset != 0)
    {
      if (!validate_type_blob (typelib,
			       offset + G_STRUCT_OFFSET (SignatureBlob, return_type),
			       offset, TRUE, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_arguments; i++)
    {
      if (!validate_arg_blob (typelib,
			      offset + sizeof (SignatureBlob) +
			      i * sizeof (ArgBlob),
			      offset,
			      error))
	return FALSE;
    }

  /* FIXME check constraints on return_value */
  /* FIXME check array-length pairs */
  return TRUE;
}

static gboolean
validate_function_blob (ValidateContext *ctx,
			guint32        offset,
			guint16        container_type,
			GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  FunctionBlob *blob;

  if (typelib->len < offset + sizeof (FunctionBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (FunctionBlob*) &typelib->data[offset];

  if (blob->blob_type != BLOB_TYPE_FUNCTION)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type %d, expected function", blob->blob_type);
      return FALSE;
    }

  if (!validate_name (typelib, "function", typelib->data, blob->name, error))
    return FALSE;

  push_context (ctx, get_string_nofail (typelib, blob->name));

  if (!validate_name (typelib, "function symbol", typelib->data, blob->symbol, error))
    return FALSE;

  if (blob->constructor)
    {
      switch (container_type)
	{
	case BLOB_TYPE_BOXED:
	case BLOB_TYPE_STRUCT:
	case BLOB_TYPE_UNION:
	case BLOB_TYPE_OBJECT:
	case BLOB_TYPE_INTERFACE:
	  break;
	default:
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Constructor not allowed");
	  return FALSE;
	}
    }

  if (blob->setter || blob->getter || blob->wraps_vfunc)
    {
      switch (container_type)
	{
	case BLOB_TYPE_OBJECT:
	case BLOB_TYPE_INTERFACE:
	  break;
	default:
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Setter, getter or wrapper not allowed");
	  return FALSE;
	}
    }

  if (blob->index)
    {
      if (!(blob->setter || blob->getter || blob->wraps_vfunc))
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Must be setter, getter or wrapper");
	  return FALSE;
	}
    }

  /* FIXME: validate index range */

  if (!validate_signature_blob (typelib, blob->signature, error))
    return FALSE;

  if (blob->constructor)
    {
      SimpleTypeBlob *simple = return_type_from_signature (typelib,
							   blob->signature,
							   error);
      InterfaceTypeBlob *iface_type;

      if (!simple)
	return FALSE;
      iface_type = get_type_blob (typelib, simple, error);
      if (!iface_type)
	return FALSE;
      if (iface_type->tag != GI_TYPE_TAG_INTERFACE &&
          (container_type == BLOB_TYPE_OBJECT ||
           container_type == BLOB_TYPE_INTERFACE))
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID,
		       "Invalid return type '%s' for constructor '%s'",
		       g_type_tag_to_string (iface_type->tag),
		       get_string_nofail (typelib, blob->symbol));
	  return FALSE;
	}
    }

  pop_context (ctx);

  return TRUE;
}

static gboolean
validate_callback_blob (ValidateContext *ctx,
			guint32        offset,
			GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  CallbackBlob *blob;

  if (typelib->len < offset + sizeof (CallbackBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (CallbackBlob*) &typelib->data[offset];

  if (blob->blob_type != BLOB_TYPE_CALLBACK)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type");
      return FALSE;
    }

  if (!validate_name (typelib, "callback", typelib->data, blob->name, error))
    return FALSE;

  push_context (ctx, get_string_nofail (typelib, blob->name));

  if (!validate_signature_blob (typelib, blob->signature, error))
    return FALSE;

  pop_context (ctx);

  return TRUE;
}

static gboolean
validate_constant_blob (GITypelib     *typelib,
			guint32        offset,
			GError       **error)
{
  guint value_size[] = {
    0, /* VOID */
    4, /* BOOLEAN */
    1, /* INT8 */
    1, /* UINT8 */
    2, /* INT16 */
    2, /* UINT16 */
    4, /* INT32 */
    4, /* UINT32 */
    8, /* INT64 */
    8, /* UINT64 */
    sizeof (gfloat),
    sizeof (gdouble),
    0, /* GTYPE */
    0, /* UTF8 */
    0, /* FILENAME */
    0, /* ARRAY */
    0, /* INTERFACE */
    0, /* GLIST */
    0, /* GSLIST */
    0, /* GHASH */
    0, /* ERROR */
    4 /* UNICHAR */
  };
  ConstantBlob *blob;
  SimpleTypeBlob *type;

  g_assert (G_N_ELEMENTS (value_size) == GI_TYPE_TAG_N_TYPES);

  if (typelib->len < offset + sizeof (ConstantBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (ConstantBlob*) &typelib->data[offset];

  if (blob->blob_type != BLOB_TYPE_CONSTANT)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type");
      return FALSE;
    }

  if (!validate_name (typelib, "constant", typelib->data, blob->name, error))
    return FALSE;

  if (!validate_type_blob (typelib, offset + G_STRUCT_OFFSET (ConstantBlob, type),
			   0, FALSE, error))
    return FALSE;

  if (!is_aligned (blob->offset))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Misaligned constant value");
      return FALSE;
    }

  type = (SimpleTypeBlob *)&typelib->data[offset + G_STRUCT_OFFSET (ConstantBlob, type)];
  if (type->flags.reserved == 0 && type->flags.reserved2 == 0)
    {
      if (type->flags.tag == 0)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Constant value type void");
	  return FALSE;
	}

      if (value_size[type->flags.tag] != 0 &&
	  blob->size != value_size[type->flags.tag])
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Constant value size mismatch");
	  return FALSE;
	}
      /* FIXME check string values */
    }

  return TRUE;
}

static gboolean
validate_value_blob (GITypelib     *typelib,
		     guint32        offset,
		     GError       **error)
{
  ValueBlob *blob;

  if (typelib->len < offset + sizeof (ValueBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (ValueBlob*) &typelib->data[offset];

  if (!validate_name (typelib, "value", typelib->data, blob->name, error))
    return FALSE;

  return TRUE;
}

static gboolean
validate_field_blob (ValidateContext *ctx,
		     guint32        offset,
		     GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  Header *header = (Header *)typelib->data;
  FieldBlob *blob;

  if (typelib->len < offset + sizeof (FieldBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (FieldBlob*) &typelib->data[offset];

  if (!validate_name (typelib, "field", typelib->data, blob->name, error))
    return FALSE;

  if (blob->has_embedded_type)
    {
      if (!validate_callback_blob (ctx, offset + header->field_blob_size, error))
        return FALSE;
    }
  else if (!validate_type_blob (typelib,
			        offset + G_STRUCT_OFFSET (FieldBlob, type),
			        0, FALSE, error))
    return FALSE;

  return TRUE;
}

static gboolean
validate_property_blob (GITypelib     *typelib,
			guint32        offset,
			GError       **error)
{
  PropertyBlob *blob;

  if (typelib->len < offset + sizeof (PropertyBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (PropertyBlob*) &typelib->data[offset];

  if (!validate_name (typelib, "property", typelib->data, blob->name, error))
    return FALSE;

  if (!validate_type_blob (typelib,
			   offset + G_STRUCT_OFFSET (PropertyBlob, type),
			   0, FALSE, error))
    return FALSE;

  return TRUE;
}

static gboolean
validate_signal_blob (GITypelib     *typelib,
		      guint32        offset,
		      guint32        container_offset,
		      GError       **error)
{
  SignalBlob *blob;
  gint n_signals;

  if (typelib->len < offset + sizeof (SignalBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (SignalBlob*) &typelib->data[offset];

  if (!validate_name (typelib, "signal", typelib->data, blob->name, error))
    return FALSE;

  if ((blob->run_first != 0) +
      (blob->run_last != 0) +
      (blob->run_cleanup != 0) != 1)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Invalid signal run flags");
      return FALSE;
    }

  if (blob->has_class_closure)
    {
      if (((CommonBlob*)&typelib->data[container_offset])->blob_type == BLOB_TYPE_OBJECT)
	{
	  ObjectBlob *object;

	  object = (ObjectBlob*)&typelib->data[container_offset];

	  n_signals = object->n_signals;
	}
      else
	{
	  InterfaceBlob *iface;

	  iface = (InterfaceBlob*)&typelib->data[container_offset];

	  n_signals = iface->n_signals;
	}

      if (blob->class_closure >= n_signals)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Invalid class closure index");
	  return FALSE;
	}
    }

  if (!validate_signature_blob (typelib, blob->signature, error))
    return FALSE;

  return TRUE;
}

static gboolean
validate_vfunc_blob (GITypelib     *typelib,
		     guint32        offset,
		     guint32        container_offset,
		     GError       **error)
{
  VFuncBlob *blob;
  gint n_vfuncs;

  if (typelib->len < offset + sizeof (VFuncBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (VFuncBlob*) &typelib->data[offset];

  if (!validate_name (typelib, "vfunc", typelib->data, blob->name, error))
    return FALSE;

  if (blob->class_closure)
    {
      if (((CommonBlob*)&typelib->data[container_offset])->blob_type == BLOB_TYPE_OBJECT)
	{
	  ObjectBlob *object;

	  object = (ObjectBlob*)&typelib->data[container_offset];

	  n_vfuncs = object->n_vfuncs;
	}
      else
	{
	  InterfaceBlob *iface;

	  iface = (InterfaceBlob*)&typelib->data[container_offset];

	  n_vfuncs = iface->n_vfuncs;
	}

      if (blob->class_closure >= n_vfuncs)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Invalid class closure index");
	  return FALSE;
	}
    }

  if (!validate_signature_blob (typelib, blob->signature, error))
    return FALSE;

  return TRUE;
}

static gboolean
validate_struct_blob (ValidateContext *ctx,
		      guint32        offset,
		      guint16        blob_type,
		      GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  StructBlob *blob;
  gint i;
  guint32 field_offset;

  if (typelib->len < offset + sizeof (StructBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (StructBlob*) &typelib->data[offset];

  if (blob->blob_type != blob_type)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type");
      return FALSE;
    }

  if (!validate_name (typelib, "struct", typelib->data, blob->name, error))
    return FALSE;

  push_context (ctx, get_string_nofail (typelib, blob->name));

  if (!blob->unregistered)
    {
      if (!validate_name (typelib, "boxed", typelib->data, blob->gtype_name, error))
	return FALSE;

      if (!validate_name (typelib, "boxed", typelib->data, blob->gtype_init, error))
	return FALSE;
    }
  else
    {
      if (blob->gtype_name || blob->gtype_init)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Gtype data in struct");
	  return FALSE;
	}
    }

  if (typelib->len < offset + sizeof (StructBlob) +
            blob->n_fields * sizeof (FieldBlob) +
            blob->n_methods * sizeof (FunctionBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  field_offset = offset + sizeof (StructBlob);
  for (i = 0; i < blob->n_fields; i++)
    {
      FieldBlob *blob = (FieldBlob*) &typelib->data[field_offset];

      if (!validate_field_blob (ctx,
				field_offset,
				error))
	return FALSE;

      field_offset += sizeof (FieldBlob);
      if (blob->has_embedded_type)
        field_offset += sizeof (CallbackBlob);
    }

  for (i = 0; i < blob->n_methods; i++)
    {
      if (!validate_function_blob (ctx,
				   field_offset +
				   i * sizeof (FunctionBlob),
				   blob_type,
				   error))
	return FALSE;
    }

  pop_context (ctx);

  return TRUE;
}

static gboolean
validate_enum_blob (ValidateContext *ctx,
		    guint32        offset,
		    guint16        blob_type,
		    GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  EnumBlob *blob;
  gint i;
  guint32 offset2;

  if (typelib->len < offset + sizeof (EnumBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (EnumBlob*) &typelib->data[offset];

  if (blob->blob_type != blob_type)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type");
      return FALSE;
    }

  if (!blob->unregistered)
    {
      if (!validate_name (typelib, "enum", typelib->data, blob->gtype_name, error))
	return FALSE;

      if (!validate_name (typelib, "enum", typelib->data, blob->gtype_init, error))
	return FALSE;
    }
  else
    {
      if (blob->gtype_name || blob->gtype_init)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Gtype data in unregistered enum");
	  return FALSE;
	}
    }

  if (!validate_name (typelib, "enum", typelib->data, blob->name, error))
    return FALSE;

  if (typelib->len < offset + sizeof (EnumBlob) +
      blob->n_values * sizeof (ValueBlob) +
      blob->n_methods * sizeof (FunctionBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  offset2 = offset + sizeof (EnumBlob);

  push_context (ctx, get_string_nofail (typelib, blob->name));

  for (i = 0; i < blob->n_values; i++, offset2 += sizeof (ValueBlob))
    {
      if (!validate_value_blob (typelib,
				offset2,
				error))
	return FALSE;

#if 0
      v1 = (ValueBlob *)&typelib->data[offset2];
      for (j = 0; j < i; j++)
	{
	  v2 = (ValueBlob *)&typelib->data[offset2 +
                                            j * sizeof (ValueBlob)];

	  if (v1->value == v2->value)
	    {

	      /* FIXME should this be an error ? */
	      g_set_error (error,
			   G_TYPELIB_ERROR,
			   G_TYPELIB_ERROR_INVALID_BLOB,
			   "Duplicate enum value");
	      return FALSE;
	    }
	}
#endif
    }

  for (i = 0; i < blob->n_methods; i++, offset2 += sizeof (FunctionBlob))
    {
      if (!validate_function_blob (ctx, offset2, BLOB_TYPE_ENUM, error))
	return FALSE;
    }

  pop_context (ctx);

  return TRUE;
}

static gboolean
validate_object_blob (ValidateContext *ctx,
		      guint32        offset,
		      GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  Header *header;
  ObjectBlob *blob;
  gint i;
  guint32 offset2;

  header = (Header *)typelib->data;

  if (typelib->len < offset + sizeof (ObjectBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (ObjectBlob*) &typelib->data[offset];

  if (blob->blob_type != BLOB_TYPE_OBJECT)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type");
      return FALSE;
    }

  if (!validate_name (typelib, "object", typelib->data, blob->gtype_name, error))
    return FALSE;

  if (!validate_name (typelib, "object", typelib->data, blob->gtype_init, error))
    return FALSE;

  if (!validate_name (typelib, "object", typelib->data, blob->name, error))
    return FALSE;

  if (blob->parent > header->n_entries)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Invalid parent index");
      return FALSE;
    }

  if (blob->parent != 0)
    {
      DirEntry *entry;

      entry = get_dir_entry_checked (typelib, blob->parent, error);
      if (!entry)
        return FALSE;
      if (entry->blob_type != BLOB_TYPE_OBJECT &&
	  (entry->local || entry->blob_type != 0))
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Parent not object");
	  return FALSE;
	}
    }

  if (blob->gtype_struct != 0)
    {
      DirEntry *entry;

      entry = get_dir_entry_checked (typelib, blob->gtype_struct, error);
      if (!entry)
        return FALSE;
      if (entry->blob_type != BLOB_TYPE_STRUCT && entry->local)
        {
          g_set_error (error,
                       G_TYPELIB_ERROR,
                       G_TYPELIB_ERROR_INVALID_BLOB,
                       "Class struct invalid type or not local");
          return FALSE;
        }
    }

  if (typelib->len < offset + sizeof (ObjectBlob) +
            (blob->n_interfaces + blob->n_interfaces % 2) * 2 +
            blob->n_fields * sizeof (FieldBlob) +
            blob->n_properties * sizeof (PropertyBlob) +
            blob->n_methods * sizeof (FunctionBlob) +
            blob->n_signals * sizeof (SignalBlob) +
            blob->n_vfuncs * sizeof (VFuncBlob) +
            blob->n_constants * sizeof (ConstantBlob))

    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  offset2 = offset + sizeof (ObjectBlob);

  for (i = 0; i < blob->n_interfaces; i++, offset2 += 2)
    {
      guint16 iface;
      DirEntry *entry;

      iface = *(guint16*)&typelib->data[offset2];
      if (iface == 0 || iface > header->n_entries)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Invalid interface index");
	  return FALSE;
	}

      entry = get_dir_entry_checked (typelib, iface, error);
      if (!entry)
        return FALSE;

      if (entry->blob_type != BLOB_TYPE_INTERFACE &&
	  (entry->local || entry->blob_type != 0))
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Not an interface");
	  return FALSE;
	}
    }

  offset2 += 2 * (blob->n_interfaces %2);

  push_context (ctx, get_string_nofail (typelib, blob->name));

  for (i = 0; i < blob->n_fields; i++, offset2 += sizeof (FieldBlob))
    {
      if (!validate_field_blob (ctx, offset2, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_properties; i++, offset2 += sizeof (PropertyBlob))
    {
      if (!validate_property_blob (typelib, offset2, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_methods; i++, offset2 += sizeof (FunctionBlob))
    {
      if (!validate_function_blob (ctx, offset2, BLOB_TYPE_OBJECT, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_signals; i++, offset2 += sizeof (SignalBlob))
    {
      if (!validate_signal_blob (typelib, offset2, offset, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_vfuncs; i++, offset2 += sizeof (VFuncBlob))
    {
      if (!validate_vfunc_blob (typelib, offset2, offset, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_constants; i++, offset2 += sizeof (ConstantBlob))
    {
      if (!validate_constant_blob (typelib, offset2, error))
	return FALSE;
    }

  pop_context (ctx);

  return TRUE;
}

static gboolean
validate_interface_blob (ValidateContext *ctx,
			 guint32        offset,
			 GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  Header *header;
  InterfaceBlob *blob;
  gint i;
  guint32 offset2;

  header = (Header *)typelib->data;

  if (typelib->len < offset + sizeof (InterfaceBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  blob = (InterfaceBlob*) &typelib->data[offset];

  if (blob->blob_type != BLOB_TYPE_INTERFACE)
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_BLOB,
		   "Wrong blob type; expected interface, got %d", blob->blob_type);
      return FALSE;
    }

  if (!validate_name (typelib, "interface", typelib->data, blob->gtype_name, error))
    return FALSE;

  if (!validate_name (typelib, "interface", typelib->data, blob->gtype_init, error))
    return FALSE;

  if (!validate_name (typelib, "interface", typelib->data, blob->name, error))
    return FALSE;

  if (typelib->len < offset + sizeof (InterfaceBlob) +
            (blob->n_prerequisites + blob->n_prerequisites % 2) * 2 +
            blob->n_properties * sizeof (PropertyBlob) +
            blob->n_methods * sizeof (FunctionBlob) +
            blob->n_signals * sizeof (SignalBlob) +
            blob->n_vfuncs * sizeof (VFuncBlob) +
            blob->n_constants * sizeof (ConstantBlob))

    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  offset2 = offset + sizeof (InterfaceBlob);

  for (i = 0; i < blob->n_prerequisites; i++, offset2 += 2)
    {
      DirEntry *entry;
      guint16 req;

      req = *(guint16*)&typelib->data[offset2];
      if (req == 0 || req > header->n_entries)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Invalid prerequisite index");
	  return FALSE;
	}

      entry = g_typelib_get_dir_entry (typelib, req);
      if (entry->blob_type != BLOB_TYPE_INTERFACE &&
	  entry->blob_type != BLOB_TYPE_OBJECT &&
	  (entry->local || entry->blob_type != 0))
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_BLOB,
		       "Not an interface or object");
	  return FALSE;
	}
    }

  offset2 += 2 * (blob->n_prerequisites % 2);

  push_context (ctx, get_string_nofail (typelib, blob->name));

  for (i = 0; i < blob->n_properties; i++, offset2 += sizeof (PropertyBlob))
    {
      if (!validate_property_blob (typelib, offset2, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_methods; i++, offset2 += sizeof (FunctionBlob))
    {
      if (!validate_function_blob (ctx, offset2, BLOB_TYPE_INTERFACE, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_signals; i++, offset2 += sizeof (SignalBlob))
    {
      if (!validate_signal_blob (typelib, offset2, offset, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_vfuncs; i++, offset2 += sizeof (VFuncBlob))
    {
      if (!validate_vfunc_blob (typelib, offset2, offset, error))
	return FALSE;
    }

  for (i = 0; i < blob->n_constants; i++, offset2 += sizeof (ConstantBlob))
    {
      if (!validate_constant_blob (typelib, offset2, error))
	return FALSE;
    }

  pop_context (ctx);

  return TRUE;
}

static gboolean
validate_union_blob (GITypelib     *typelib,
		     guint32        offset,
		     GError       **error)
{
  return TRUE;
}

static gboolean
validate_blob (ValidateContext *ctx,
	       guint32          offset,
	       GError         **error)
{
  GITypelib *typelib = ctx->typelib;
  CommonBlob *common;

  if (typelib->len < offset + sizeof (CommonBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  common = (CommonBlob*)&typelib->data[offset];

  switch (common->blob_type)
    {
    case BLOB_TYPE_FUNCTION:
      if (!validate_function_blob (ctx, offset, 0, error))
	return FALSE;
      break;
    case BLOB_TYPE_CALLBACK:
      if (!validate_callback_blob (ctx, offset, error))
	return FALSE;
      break;
    case BLOB_TYPE_STRUCT:
    case BLOB_TYPE_BOXED:
      if (!validate_struct_blob (ctx, offset, common->blob_type, error))
	return FALSE;
      break;
    case BLOB_TYPE_ENUM:
    case BLOB_TYPE_FLAGS:
      if (!validate_enum_blob (ctx, offset, common->blob_type, error))
	return FALSE;
      break;
    case BLOB_TYPE_OBJECT:
      if (!validate_object_blob (ctx, offset, error))
	return FALSE;
      break;
    case BLOB_TYPE_INTERFACE:
      if (!validate_interface_blob (ctx, offset, error))
	return FALSE;
      break;
    case BLOB_TYPE_CONSTANT:
      if (!validate_constant_blob (typelib, offset, error))
	return FALSE;
      break;
    case BLOB_TYPE_UNION:
      if (!validate_union_blob (typelib, offset, error))
	return FALSE;
      break;
    default:
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID_ENTRY,
		   "Invalid blob type");
      return FALSE;
    }

  return TRUE;
}

static gboolean
validate_directory (ValidateContext   *ctx,
		    GError            **error)
{
  GITypelib *typelib = ctx->typelib;
  Header *header = (Header *)typelib->data;
  DirEntry *entry;
  gint i;

  if (typelib->len < header->directory + header->n_entries * sizeof (DirEntry))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  for (i = 0; i < header->n_entries; i++)
    {
      entry = g_typelib_get_dir_entry (typelib, i + 1);

      if (!validate_name (typelib, "entry", typelib->data, entry->name, error))
	return FALSE;

      if ((entry->local && entry->blob_type == BLOB_TYPE_INVALID) ||
	  entry->blob_type > BLOB_TYPE_UNION)
	{
	  g_set_error (error,
		       G_TYPELIB_ERROR,
		       G_TYPELIB_ERROR_INVALID_DIRECTORY,
		       "Invalid entry type");
	  return FALSE;
	}

      if (i < header->n_local_entries)
	{
	  if (!entry->local)
	    {
	      g_set_error (error,
			   G_TYPELIB_ERROR,
			   G_TYPELIB_ERROR_INVALID_DIRECTORY,
			   "Too few local directory entries");
	      return FALSE;
	    }

	  if (!is_aligned (entry->offset))
	    {
	      g_set_error (error,
			   G_TYPELIB_ERROR,
			   G_TYPELIB_ERROR_INVALID_DIRECTORY,
			   "Misaligned entry");
	      return FALSE;
	    }

	  if (!validate_blob (ctx, entry->offset, error))
	    return FALSE;
	}
      else
	{
	  if (entry->local)
	    {
	      g_set_error (error,
			   G_TYPELIB_ERROR,
			   G_TYPELIB_ERROR_INVALID_DIRECTORY,
			   "Too many local directory entries");
	      return FALSE;
	    }

	  if (!validate_name (typelib, "namespace", typelib->data, entry->offset, error))
	    return FALSE;
	}
    }

  return TRUE;
}

static gboolean
validate_attributes (ValidateContext *ctx,
		     GError       **error)
{
  GITypelib *typelib = ctx->typelib;
  Header *header = (Header *)typelib->data;

  if (header->size < header->attributes + header->n_attributes * sizeof (AttributeBlob))
    {
      g_set_error (error,
		   G_TYPELIB_ERROR,
		   G_TYPELIB_ERROR_INVALID,
		   "The buffer is too short");
      return FALSE;
    }

  return TRUE;
}

static void
prefix_with_context (GError **error,
		     const char *section,
		     ValidateContext *ctx)
{
  GString *str = g_string_new (NULL);
  GSList *link;
  char *buf;

  link = ctx->context_stack;
  if (!link)
    {
      g_prefix_error (error, "In %s:", section);
      return;
    }

  for (; link; link = link->next)
    {
      g_string_append (str, link->data);
      if (link->next)
	g_string_append_c (str, '/');
    }
  g_string_append_c (str, ')');
  buf = g_string_free (str, FALSE);
  g_prefix_error (error, "In %s (Context: %s): ", section, buf);
  g_free (buf);
}

gboolean
g_typelib_validate (GITypelib     *typelib,
		     GError       **error)
{
  ValidateContext ctx;
  ctx.typelib = typelib;
  ctx.context_stack = NULL;

  if (!validate_header (&ctx, error))
    {
      prefix_with_context (error, "In header", &ctx);
      return FALSE;
    }

  if (!validate_directory (&ctx, error))
    {
      prefix_with_context (error, "directory", &ctx);
      return FALSE;
    }

  if (!validate_attributes (&ctx, error))
    {
      prefix_with_context (error, "attributes", &ctx);
      return FALSE;
    }

  return TRUE;
}

GQuark
g_typelib_error_quark (void)
{
  static GQuark quark = 0;
  if (quark == 0)
    quark = g_quark_from_static_string ("g-typelib-error-quark");
  return quark;
}

static void
_g_typelib_do_dlopen (GITypelib *typelib)
{
  Header *header;
  const char *shlib_str;

  header = (Header *) typelib->data;
  /* note that NULL shlib means to open the main app, which is allowed */
  if (header->shared_library)
    shlib_str = g_typelib_get_string (typelib, header->shared_library);
  else
    shlib_str = NULL;

  if (shlib_str != NULL && shlib_str[0] != '\0')
    {
      gchar **shlibs;
      gint i;

      /* shared-library is a comma-separated list of libraries */
      shlibs = g_strsplit (shlib_str, ",", 0);

       /* We load all passed libs unconditionally as if the same library is loaded
        * again with g_module_open(), the same file handle will be returned. See bug:
        * http://bugzilla.gnome.org/show_bug.cgi?id=555294
        */
      for (i = 0; shlibs[i]; i++)
        {
          GModule *module;

          /* Glade's autoconnect feature and OpenGL's extension mechanism
           * as used by Clutter rely on g_module_open(NULL) to work as a means of
           * accessing the app's symbols. This keeps us from using
           * G_MODULE_BIND_LOCAL. BIND_LOCAL may have other issues as well;
           * in general libraries are not expecting multiple copies of
           * themselves and are not expecting to be unloaded. So we just
           * load modules globally for now.
           */

          module = g_module_open (shlibs[i], G_MODULE_BIND_LAZY);

          if (module == NULL)
            {
              GString *shlib_full = g_string_new (shlibs[i]);

              module = g_module_open (shlib_full->str, G_MODULE_BIND_LAZY);
              if (module == NULL)
                {
                  g_string_overwrite (shlib_full, strlen (shlib_full->str)-2, SHLIB_SUFFIX);
                  module = g_module_open (shlib_full->str, G_MODULE_BIND_LAZY);
                }

              g_string_free (shlib_full, TRUE);
            }

          if (module == NULL)
            {
              g_warning ("Failed to load shared library '%s' referenced by the typelib: %s",
                         shlibs[i], g_module_error ());
            }
          else
            {
              typelib->modules = g_list_append (typelib->modules, module);
            }
       }

      g_strfreev (shlibs);
    }
  else
    {
      /* If there's no shared-library entry for this module, assume that
       * the module is for the application.  Some of the hand-written .gir files
       * in gobject-introspection don't have shared-library entries, but no one
       * is really going to be calling g_module_symbol on them either.
       */
      GModule *module = g_module_open (NULL, 0);
      if (module == NULL)
        g_warning ("gtypelib.c: Failed to g_module_open (NULL): %s", g_module_error ());
      else
        typelib->modules = g_list_prepend (typelib->modules, module);
    }
}

static inline void
_g_typelib_ensure_open (GITypelib *typelib)
{
  if (typelib->open_attempted)
    return;
  typelib->open_attempted = TRUE;
  _g_typelib_do_dlopen (typelib);
}

/**
 * g_typelib_new_from_memory: (skip)
 * @memory: address of memory chunk containing the typelib
 * @len: length of memory chunk containing the typelib
 * @error: a #GError
 *
 * Creates a new #GITypelib from a memory location.  The memory block
 * pointed to by @typelib will be automatically g_free()d when the
 * repository is destroyed.
 *
 * Return value: the new #GITypelib
 **/
GITypelib *
g_typelib_new_from_memory (guint8  *memory, 
			   gsize    len,
			   GError **error)
{
  GITypelib *meta;

  if (!validate_header_basic (memory, len, error))
    return NULL;

  meta = g_slice_new0 (GITypelib);
  meta->data = memory;
  meta->len = len;
  meta->owns_memory = TRUE;
  meta->modules = NULL;

  return meta;
}

/**
 * g_typelib_new_from_const_memory: (skip)
 * @memory: address of memory chunk containing the typelib
 * @len: length of memory chunk containing the typelib
 * @error: A #GError
 *
 * Creates a new #GITypelib from a memory location.
 *
 * Return value: the new #GITypelib
 **/
GITypelib *
g_typelib_new_from_const_memory (const guchar *memory, 
				 gsize         len,
				 GError      **error)
{
  GITypelib *meta;

  if (!validate_header_basic (memory, len, error))
    return NULL;

  meta = g_slice_new0 (GITypelib);
  meta->data = (guchar *) memory;
  meta->len = len;
  meta->owns_memory = FALSE;
  meta->modules = NULL;

  return meta;
}

/**
 * g_typelib_new_from_mapped_file: (skip)
 * @mfile: a #GMappedFile, that will be free'd when the repository is destroyed
 * @error: a #GError
 *
 * Creates a new #GITypelib from a #GMappedFile.
 *
 * Return value: the new #GITypelib
 **/
GITypelib *
g_typelib_new_from_mapped_file (GMappedFile  *mfile,
				GError      **error)
{
  GITypelib *meta;
  guint8 *data = (guint8 *) g_mapped_file_get_contents (mfile);
  gsize len = g_mapped_file_get_length (mfile);

  if (!validate_header_basic (data, len, error))
    return NULL;

  meta = g_slice_new0 (GITypelib);
  meta->mfile = mfile;
  meta->owns_memory = FALSE;
  meta->data = data; 
  meta->len = len;

  return meta;
}

/**
 * g_typelib_free:
 * @typelib: a #GITypelib
 *
 * Free a #GITypelib.
 **/
void
g_typelib_free (GITypelib *typelib)
{
  if (typelib->mfile)
    g_mapped_file_unref (typelib->mfile);
  else
    if (typelib->owns_memory)
      g_free (typelib->data);
  if (typelib->modules)
    {
      g_list_foreach (typelib->modules, (GFunc) g_module_close, NULL);
      g_list_free (typelib->modules);
    }
  g_slice_free (GITypelib, typelib);
}

const gchar *
g_typelib_get_namespace (GITypelib *typelib)
{
  return g_typelib_get_string (typelib, ((Header *) typelib->data)->namespace);
}

/**
 * g_typelib_symbol:
 * @typelib: the typelib
 * @symbol_name: name of symbol to be loaded
 * @symbol: returns a pointer to the symbol value
 *
 * Loads a symbol from #GITypelib.
 *
 * Return value: #TRUE on success
 **/
gboolean
g_typelib_symbol (GITypelib *typelib, const char *symbol_name, gpointer *symbol)
{
  GList *l;

  _g_typelib_ensure_open (typelib);

  /*
   * The reason for having multiple modules dates from gir-repository
   * when it was desired to inject code (accessors, etc.) into an
   * existing library.  In that situation, the first module listed
   * will be the custom one, which overrides the main one.  A bit
   * inefficient, but the problem will go away when gir-repository
   * does.
   *
   * For modules with no shared library, we dlopen'd the current
   * process above.
   */
  for (l = typelib->modules; l; l = l->next)
    {
      GModule *module = l->data;

      if (g_module_symbol (module, symbol_name, symbol))
        return TRUE;
    }

  return FALSE;
}
