Bug 552371 – implement struct field get/set

Add convenience functions g_field_info_set_field() and
g_field_info_get_field() to set and get fields based on the offsets
in GIFieldInfo.

svn path=/trunk/; revision=929

4 files changed, 325 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 721a9a51..ff663e8f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,10 +1,19 @@
+2008-11-16  Owen Taylor  <otaylor@redhat.com>
+
+	Bug 552371 – implement struct field get/set
+
+	* girepository/gfield.c girepository/girepository.h: Add
+	convenience functions g_field_info_set_field() and
+	g_field_info_get_field() to set and get fields based on the
+	offsets in GIFieldInfo.
+
 2008-11-16  Andreas Rottmann  <a.rottmann@gmx.at>
 
 	Bug 560241 - Out-arguments should not be marked as being pointers
 	in all cases
 
 	* girepository/girparser.c: Improved logic for out arguments.
-	
+
 2008-11-16  Andreas Rottmann  <a.rottmann@gmx.at>
 
 	Bug 559601 - Pointers in structs/unions unduly treated as arrays
diff --git a/girepository/Makefile.am b/girepository/Makefile.am
index b58288e8..f98dda29 100644
--- a/girepository/Makefile.am
+++ b/girepository/Makefile.am
@@ -12,6 +12,7 @@ libgirepository_la_SOURCES =			\
 	girepository.c				\
 	gtypelib.h				\
 	gtypelib.c				\
+	gfield.c				\
 	ginfo.c					\
 	girffi.c				\
 	girffi.h				\
diff --git a/girepository/gfield.c b/girepository/gfield.c
new file mode 100644
index 00000000..79a5a0d5
--- /dev/null
+++ b/girepository/gfield.c
@@ -0,0 +1,308 @@
+#include "girepository.h"
+
+/**
+ * g_field_info_get_field:
+ * @field_info: a #GIFieldInfo
+ * @mem: pointer to a block of memory representing a C structure or union
+ * @value: a #GArgument into which to store the value retrieved
+ *
+ * Reads a field identified by a #GFieldInfo from a C structure or
+ * union.  This only handles fields of simple C types. It will fail
+ * for a field of a composite type like a nested structure or union
+ * even if that is actually readable.
+ *
+ * Returns: %TRUE if reading the field succeeded, otherwise %FALSE
+ */
+gboolean
+g_field_info_get_field (GIFieldInfo *field_info,
+			gpointer     mem,
+			GArgument   *value)
+{
+    int offset;
+    GITypeInfo *type_info;
+    gboolean result = FALSE;
+
+    if (!g_field_info_get_flags (field_info) & GI_FIELD_IS_READABLE)
+      return FALSE;
+
+    offset = g_field_info_get_offset (field_info);
+    type_info = g_field_info_get_type (field_info);
+
+    if (g_type_info_is_pointer (type_info))
+      {
+	value->v_pointer = G_STRUCT_MEMBER(gpointer, mem, offset);
+	result = TRUE;
+      }
+    else
+      {
+	switch (g_type_info_get_tag (type_info))
+	  {
+	  case GI_TYPE_TAG_VOID:
+	    g_warning("Field %s: should not be have void type",
+		      g_base_info_get_name ((GIBaseInfo *)field_info));
+	    break;
+	  case GI_TYPE_TAG_BOOLEAN:
+	    value->v_boolean = G_STRUCT_MEMBER(gboolean, mem, offset) != FALSE;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT8:
+	  case GI_TYPE_TAG_UINT8:
+	    value->v_uint8 = G_STRUCT_MEMBER(guint8, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT16:
+	  case GI_TYPE_TAG_UINT16:
+	    value->v_uint16 = G_STRUCT_MEMBER(guint16, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT32:
+	  case GI_TYPE_TAG_UINT32:
+	  case GI_TYPE_TAG_INT:
+	  case GI_TYPE_TAG_UINT:
+	    value->v_uint32 = G_STRUCT_MEMBER(guint32, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT64:
+	  case GI_TYPE_TAG_UINT64:
+	    value->v_uint64 = G_STRUCT_MEMBER(guint64, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_LONG:
+	  case GI_TYPE_TAG_ULONG:
+	    value->v_ulong = G_STRUCT_MEMBER(gulong, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_SSIZE:
+	  case GI_TYPE_TAG_SIZE:
+	  case GI_TYPE_TAG_GTYPE:
+	    value->v_size = G_STRUCT_MEMBER(gsize, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_FLOAT:
+	    value->v_float = G_STRUCT_MEMBER(gfloat, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_DOUBLE:
+	    value->v_double = G_STRUCT_MEMBER(gdouble, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_TIME_T:
+	    value->v_long = G_STRUCT_MEMBER(time_t, mem, offset);
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_UTF8:
+	  case GI_TYPE_TAG_FILENAME:
+	  case GI_TYPE_TAG_ARRAY:
+	  case GI_TYPE_TAG_GLIST:
+	  case GI_TYPE_TAG_GSLIST:
+	  case GI_TYPE_TAG_GHASH:
+	    g_warning("Field %s: type %s should have is_pointer set",
+		      g_base_info_get_name ((GIBaseInfo *)field_info),
+		      g_type_tag_to_string (g_type_info_get_tag (type_info)));
+	    break;
+	  case GI_TYPE_TAG_ERROR:
+	    /* Needs to be handled by the language binding directly */
+	    break;
+	  case GI_TYPE_TAG_INTERFACE:
+	    {
+	      GIBaseInfo *interface = g_type_info_get_interface (type_info);
+	      switch (g_base_info_get_type (interface))
+		{
+		case GI_INFO_TYPE_STRUCT:
+		case GI_INFO_TYPE_UNION:
+		case GI_INFO_TYPE_BOXED:
+		  /* Needs to be handled by the language binding directly */
+		  break;
+		case GI_INFO_TYPE_OBJECT:
+		  break;
+		case GI_INFO_TYPE_ENUM:
+		case GI_INFO_TYPE_FLAGS:
+		  /* Not yet implemented */
+		  break;
+		case GI_INFO_TYPE_VFUNC:
+		case GI_INFO_TYPE_CALLBACK:
+		  g_warning("Field%s: Interface type %d should have is_pointer set",
+			    g_base_info_get_name ((GIBaseInfo *)field_info),
+			    g_base_info_get_type (interface));
+		  break;
+		case GI_INFO_TYPE_INVALID:
+		case GI_INFO_TYPE_INTERFACE:
+		case GI_INFO_TYPE_FUNCTION:
+		case GI_INFO_TYPE_CONSTANT:
+		case GI_INFO_TYPE_ERROR_DOMAIN:
+		case GI_INFO_TYPE_VALUE:
+		case GI_INFO_TYPE_SIGNAL:
+		case GI_INFO_TYPE_PROPERTY:
+		case GI_INFO_TYPE_FIELD:
+		case GI_INFO_TYPE_ARG:
+		case GI_INFO_TYPE_TYPE:
+		case GI_INFO_TYPE_UNRESOLVED:
+		  g_warning("Field %s: Interface type %d not expected",
+			    g_base_info_get_name ((GIBaseInfo *)field_info),
+			    g_base_info_get_type (interface));
+		  break;
+		}
+
+	      g_base_info_unref ((GIBaseInfo *)interface);
+	      break;
+	    }
+	    break;
+	  }
+      }
+
+    g_base_info_unref ((GIBaseInfo *)field_info);
+
+    return result;
+}
+
+/**
+ * g_field_info_set_field:
+ * @field_info: a #GIFieldInfo
+ * @mem: pointer to a block of memory representing a C structure or union
+ * @value: a #GArgument holding the value to store
+ *
+ * Writes a field identified by a #GFieldInfo to a C structure or
+ * union.  This only handles fields of simple C types. It will fail
+ * for a field of a composite type like a nested structure or union
+ * even if that is actually writable. Note also that that it will refuse
+ * to write fields where memory management would by required. A field
+ * with a type such as 'char *' must be set with a setter function.
+ *
+ * Returns: %TRUE if reading the field succeeded, otherwise %FALSE
+ */
+gboolean
+g_field_info_set_field (GIFieldInfo     *field_info,
+			gpointer         mem,
+			const GArgument *value)
+{
+    int offset;
+    GITypeInfo *type_info;
+    gboolean result = FALSE;
+
+    if (!g_field_info_get_flags (field_info) & GI_FIELD_IS_WRITABLE)
+      return FALSE;
+
+    offset = g_field_info_get_offset (field_info);
+    type_info = g_field_info_get_type (field_info);
+
+    if (!g_type_info_is_pointer (type_info))
+      {
+	switch (g_type_info_get_tag (type_info))
+	  {
+	  case GI_TYPE_TAG_VOID:
+	    g_warning("Field %s: should not be have void type",
+		      g_base_info_get_name ((GIBaseInfo *)field_info));
+	    break;
+	  case GI_TYPE_TAG_BOOLEAN:
+	    G_STRUCT_MEMBER(gboolean, mem, offset) = value->v_boolean != FALSE;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT8:
+	  case GI_TYPE_TAG_UINT8:
+	    G_STRUCT_MEMBER(guint8, mem, offset) = value->v_uint8;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT16:
+	  case GI_TYPE_TAG_UINT16:
+	    G_STRUCT_MEMBER(guint16, mem, offset) = value->v_uint16;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT32:
+	  case GI_TYPE_TAG_UINT32:
+	  case GI_TYPE_TAG_INT:
+	  case GI_TYPE_TAG_UINT:
+	    G_STRUCT_MEMBER(guint32, mem, offset) = value->v_uint32;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_INT64:
+	  case GI_TYPE_TAG_UINT64:
+	    G_STRUCT_MEMBER(guint64, mem, offset) = value->v_uint64;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_LONG:
+	  case GI_TYPE_TAG_ULONG:
+	    G_STRUCT_MEMBER(gulong, mem, offset)= value->v_ulong;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_SSIZE:
+	  case GI_TYPE_TAG_SIZE:
+	  case GI_TYPE_TAG_GTYPE:
+	    G_STRUCT_MEMBER(gsize, mem, offset) = value->v_size;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_FLOAT:
+	    G_STRUCT_MEMBER(gfloat, mem, offset) = value->v_float;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_DOUBLE:
+	    G_STRUCT_MEMBER(gdouble, mem, offset)= value->v_double;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_TIME_T:
+	    G_STRUCT_MEMBER(time_t, mem, offset) = value->v_long;
+	    result = TRUE;
+	    break;
+	  case GI_TYPE_TAG_UTF8:
+	  case GI_TYPE_TAG_FILENAME:
+	  case GI_TYPE_TAG_ARRAY:
+	  case GI_TYPE_TAG_GLIST:
+	  case GI_TYPE_TAG_GSLIST:
+	  case GI_TYPE_TAG_GHASH:
+	    g_warning("Field %s: type %s should have is_pointer set",
+		      g_base_info_get_name ((GIBaseInfo *)field_info),
+		      g_type_tag_to_string (g_type_info_get_tag (type_info)));
+	    break;
+	  case GI_TYPE_TAG_ERROR:
+	    /* Needs to be handled by the language binding directly */
+	    break;
+	  case GI_TYPE_TAG_INTERFACE:
+	    {
+	      GIBaseInfo *interface = g_type_info_get_interface (type_info);
+	      switch (g_base_info_get_type (interface))
+		{
+		case GI_INFO_TYPE_STRUCT:
+		case GI_INFO_TYPE_UNION:
+		case GI_INFO_TYPE_BOXED:
+		  /* Needs to be handled by the language binding directly */
+		  break;
+		case GI_INFO_TYPE_OBJECT:
+		  break;
+		case GI_INFO_TYPE_ENUM:
+		case GI_INFO_TYPE_FLAGS:
+		  /* Not yet implemented */
+		  break;
+		case GI_INFO_TYPE_VFUNC:
+		case GI_INFO_TYPE_CALLBACK:
+		  g_warning("Field%s: Interface type %d should have is_pointer set",
+			    g_base_info_get_name ((GIBaseInfo *)field_info),
+			    g_base_info_get_type (interface));
+		  break;
+		case GI_INFO_TYPE_INVALID:
+		case GI_INFO_TYPE_INTERFACE:
+		case GI_INFO_TYPE_FUNCTION:
+		case GI_INFO_TYPE_CONSTANT:
+		case GI_INFO_TYPE_ERROR_DOMAIN:
+		case GI_INFO_TYPE_VALUE:
+		case GI_INFO_TYPE_SIGNAL:
+		case GI_INFO_TYPE_PROPERTY:
+		case GI_INFO_TYPE_FIELD:
+		case GI_INFO_TYPE_ARG:
+		case GI_INFO_TYPE_TYPE:
+		case GI_INFO_TYPE_UNRESOLVED:
+		  g_warning("Field %s: Interface type %d not expected",
+			    g_base_info_get_name ((GIBaseInfo *)field_info),
+			    g_base_info_get_type (interface));
+		  break;
+		}
+
+	      g_base_info_unref ((GIBaseInfo *)interface);
+	      break;
+	    }
+	    break;
+	  }
+      }
+
+    g_base_info_unref ((GIBaseInfo *)field_info);
+
+    return result;
+}
diff --git a/girepository/girepository.h b/girepository/girepository.h
index 46082e03..fc5768c5 100644
--- a/girepository/girepository.h
+++ b/girepository/girepository.h
@@ -356,6 +356,12 @@ gint                   g_field_info_get_size       (GIFieldInfo *info);
 gint                   g_field_info_get_offset     (GIFieldInfo *info);
 GITypeInfo *           g_field_info_get_type       (GIFieldInfo *info);
 
+gboolean g_field_info_get_field (GIFieldInfo     *field_info,
+				 gpointer         mem,
+				 GArgument       *value);
+gboolean g_field_info_set_field (GIFieldInfo     *field_info,
+				 gpointer         mem,
+				 const GArgument *value);
 
 /* GIUnionInfo */
 gint                   g_union_info_get_n_fields  (GIUnionInfo *info);