Clarify role of dataProper

diff --git a/src/backend/utils/adt/jsonb_support.c b/src/backend/utils/adt/jsonb_support.c
index 3b8227548e27f48041c24a68c8ffc00b18574f38..256c3823cbcfd5cccfd7caae36612e33064bf565 100644 (file)
--- a/src/backend/utils/adt/jsonb_support.c
+++ b/src/backend/utils/adt/jsonb_support.c
@@ -36,13 +36,6 @@
 #define JBE_ISBOOL_TRUE(he_)   (((he_).entry & JENTRY_TYPEMASK) == JENTRY_ISTRUE)
 #define JBE_ISBOOL_FALSE(he_)  (JBE_ISBOOL(he_) && !JBE_ISBOOL_TRUE(he_))
 
-/* Macros give offset  */
-#define JBE_ENDPOS(he_) ((he_).entry & JENTRY_POSMASK)
-#define JBE_OFF(he_) (JBE_ISFIRST(he_) ? 0 : JBE_ENDPOS((&(he_))[-1]))
-#define JBE_LEN(he_) (JBE_ISFIRST(he_) \
-                     ? JBE_ENDPOS(he_) \
-                     : JBE_ENDPOS(he_) - JBE_ENDPOS((&(he_))[-1]))
-
 typedef struct CompressState
 {
    char       *begin;
@@ -674,8 +667,10 @@ JsonbIteratorNext(JsonbIterator ** it, JsonbValue * v, bool skipNested)
 
    /*
     * Encode all possible states in the "type" integer.  This is possible
-    * because enum members of JsonbIterator->state use different bit values
-    * than JB_FLAG_ARRAY/JB_FLAG_OBJECT.  See definition of JsonbIterator
+    * because enum constants within JsonbIterator.containerType use different
+    * bit values than JB_FLAG_ARRAY/JB_FLAG_OBJECT.
+    *
+    * See definition of JsonbIterator
     */
    switch ((*it)->containerType | (*it)->state)
    {
@@ -885,7 +880,7 @@ parseBuffer(JsonbIterator * it, char *buffer)
    switch (it->containerType)
    {
        case JB_FLAG_ARRAY:
-           it->containerData =
+           it->dataProper =
                (char *) it->metaArray + it->nElems * sizeof(JEntry);
            it->isScalar = (header & JB_FLAG_SCALAR) != 0;
            /* This is either a "raw scalar", or an array */
@@ -897,7 +892,7 @@ parseBuffer(JsonbIterator * it, char *buffer)
             *
             * Each key and each value have Jentry metadata.
             */
-           it->containerData =
+           it->dataProper =
                (char *) it->metaArray + it->nElems * sizeof(JEntry) * 2;
            break;
        default:
@@ -911,7 +906,7 @@ formAnswer(JsonbIterator ** it, JsonbValue * v, JEntry * e, bool skipNested)
    if (JBE_ISSTRING(*e))
    {
        v->type = jbvString;
-       v->string.val = (*it)->containerData + JBE_OFF(*e);
+       v->string.val = (*it)->dataProper + JBE_OFF(*e);
        v->string.len = JBE_LEN(*e);
        v->size = sizeof(JEntry) + v->string.len;
 
@@ -928,7 +923,7 @@ formAnswer(JsonbIterator ** it, JsonbValue * v, JEntry * e, bool skipNested)
    else if (JBE_ISNUMERIC(*e))
    {
        v->type = jbvNumeric;
-       v->numeric = (Numeric) ((*it)->containerData + INTALIGN(JBE_OFF(*e)));
+       v->numeric = (Numeric) ((*it)->dataProper + INTALIGN(JBE_OFF(*e)));
 
        v->size = 2 * sizeof(JEntry) + VARSIZE_ANY(v->numeric);
 
@@ -944,7 +939,7 @@ formAnswer(JsonbIterator ** it, JsonbValue * v, JEntry * e, bool skipNested)
    else if (skipNested)
    {
        v->type = jbvBinary;
-       v->binary.data = (*it)->containerData + INTALIGN(JBE_OFF(*e));
+       v->binary.data = (*it)->dataProper + INTALIGN(JBE_OFF(*e));
        v->binary.len = JBE_LEN(*e) - (INTALIGN(JBE_OFF(*e)) - JBE_OFF(*e));
        v->size = v->binary.len + 2 * sizeof(JEntry);
 
@@ -954,7 +949,7 @@ formAnswer(JsonbIterator ** it, JsonbValue * v, JEntry * e, bool skipNested)
    {
        JsonbIterator *nit = palloc(sizeof(*nit));
 
-       parseBuffer(nit, (*it)->containerData + INTALIGN(JBE_OFF(*e)));
+       parseBuffer(nit, (*it)->dataProper + INTALIGN(JBE_OFF(*e)));
        nit->next = *it;
        *it = nit;
 

diff --git a/src/include/utils/jsonb.h b/src/include/utils/jsonb.h
index 7d61a288212c12d202a77b4eac910a6c4d92db79..8a3ac83680c0aea53b6bdc232c618cae36a04ecd 100644 (file)
--- a/src/include/utils/jsonb.h
+++ b/src/include/utils/jsonb.h
@@ -48,6 +48,13 @@
 #define WJB_BEGIN_OBJECT   (0x020)
 #define WJB_END_OBJECT     (0x040)
 
+/* Macros give offset  */
+#define JBE_ENDPOS(he_) ((he_).entry & JENTRY_POSMASK)
+#define JBE_OFF(he_) (JBE_ISFIRST(he_) ? 0 : JBE_ENDPOS((&(he_))[-1]))
+#define JBE_LEN(he_) (JBE_ISFIRST(he_) \
+                     ? JBE_ENDPOS(he_) \
+                     : JBE_ENDPOS(he_) - JBE_ENDPOS((&(he_))[-1]))
+
 /*
  * When using a GIN index for jsonb, we choose to index both keys and values.
  * The storage format is "text" values, with K, V, or N prepended to the string
@@ -183,18 +190,17 @@ typedef struct JsonbIterator
    JEntry     *metaArray;
 
    /*
-    * Jentry items.  Note that this points just past metaArray (straight to
-    * items proper).
-    *
-    * char pointer due to alignment considerations
+    * Data proper.  Note that this points just past metaArray.  We use
+    * metaArray metadata (Jentrys) with JBE_OFF() macro to find appropriate
+    * offsets into this array.
     */
-   char       *containerData;
+   char       *dataProper;
 
    /*
     * Enum members should be freely OR'ed with JB_FLAG_ARRAY/JB_FLAG_OBJECT
     * with possibility of decoding.
     *
-    * See space optimization in JsonbIteratorGet()
+    * See optimization in JsonbIteratorNext()
     */
    enum
    {