CDRIVER-2796 more bson_iter_overwrite functions

Add bson_iter_overwrite_date_time, bson_iter_overwrite_oid, and
bson_iter_overwrite_timestamp.

Author: ajdavis

NEWS

@@ -9,6 +9,9 @@ Features:
     and all bson headers are under bson/. The preferred way of including the
     headers are mongoc/mongoc.h and bson/bson.h respectively.
     Forwarding headers in the root are provided for backwards compatibility.
+  * Additional functions bson_iter_overwrite_date_time, bson_iter_overwrite_oid,
+    and bson_iter_overwrite_timestamp. All fixed-length BSON values can now be
+    updated in place.
 
 Bug fixes:
 

src/libbson/doc/bson_iter_overwrite_date_time.rst

@@ -0,0 +1,28 @@
+:man_page: bson_iter_overwrite_date_time
+
+bson_iter_overwrite_date_time()
+===============================
+
+Synopsis
+--------
+
+.. code-block:: c
+
+  void
+  bson_iter_overwrite_date_time (bson_iter_t *iter, int64_t value);
+
+Parameters
+----------
+
+* ``iter``: A :symbol:`bson_iter_t`.
+* ``value``: The date and time as specified in milliseconds since the UNIX epoch.
+
+Description
+-----------
+
+The ``bson_iter_overwrite_date_time()`` function shall overwrite the contents of a BSON_TYPE_DATE_TIME element in place.
+
+This may only be done when the underlying bson document allows mutation.
+
+It is a programming error to call this function when ``iter`` is not observing an element of type BSON_TYPE_DATE_TIME.
+

src/libbson/doc/bson_iter_overwrite_oid.rst

@@ -0,0 +1,28 @@
+:man_page: bson_iter_overwrite_oid
+
+bson_iter_overwrite_oid()
+=========================
+
+Synopsis
+--------
+
+.. code-block:: c
+
+  void
+  bson_iter_overwrite_oid (bson_iter_t *iter, const bson_oid_t *value);
+
+Parameters
+----------
+
+* ``iter``: A :symbol:`bson_iter_t`.
+* ``oid``: A :symbol:`bson_oid_t`.
+
+Description
+-----------
+
+The ``bson_iter_overwrite_oid()`` function shall overwrite the contents of a BSON_TYPE_OID element in place.
+
+This may only be done when the underlying bson document allows mutation.
+
+It is a programming error to call this function when ``iter`` is not observing an element of type BSON_TYPE_OID.
+

src/libbson/doc/bson_iter_overwrite_timestamp.rst

@@ -0,0 +1,31 @@
+:man_page: bson_iter_overwrite_timestamp
+
+bson_iter_overwrite_timestamp()
+===============================
+
+Synopsis
+--------
+
+.. code-block:: c
+
+  void
+  bson_iter_overwrite_timestamp (bson_iter_t *iter,
+                                 uint32_t timestamp,
+                                 uint32_t increment);
+
+Parameters
+----------
+
+* ``iter``: A :symbol:`bson_iter_t`.
+* ``timestamp``: A uint32_t.
+* ``increment``: A uint32_t.
+
+Description
+-----------
+
+The ``bson_iter_overwrite_timestamp()`` function shall overwrite the contents of a BSON_TYPE_TIMESTAMP element in place.
+
+This may only be done when the underlying bson document allows mutation.
+
+It is a programming error to call this function when ``iter`` is not observing an element of type BSON_TYPE_TIMESTAMP.
+

src/libbson/doc/bson_iter_t.rst

@@ -115,10 +115,13 @@ The :symbol:`bson_t` *MUST* be valid for the lifetime of the iter and it is an e
     bson_iter_offset
     bson_iter_oid
     bson_iter_overwrite_bool
+    bson_iter_overwrite_date_time
     bson_iter_overwrite_decimal128
     bson_iter_overwrite_double
     bson_iter_overwrite_int32
     bson_iter_overwrite_int64
+    bson_iter_overwrite_oid
+    bson_iter_overwrite_timestamp
     bson_iter_recurse
     bson_iter_regex
     bson_iter_symbol

src/libbson/src/bson/bson-iter.c

@@ -18,7 +18,7 @@
 #include "bson/bson-iter.h"
 #include "bson/bson-config.h"
 #include "bson/bson-decimal128.h"
-
+#include "bson-types.h"
 
 #define ITER_TYPE(i) ((bson_type_t) * ((i)->raw + (i)->type))
 
@@ -2185,6 +2185,46 @@ bson_iter_overwrite_bool (bson_iter_t *iter, /* IN */
 }
 
 
+void
+bson_iter_overwrite_oid (bson_iter_t *iter, const bson_oid_t *value)
+{
+   BSON_ASSERT (iter);
+
+   if (ITER_TYPE (iter) == BSON_TYPE_OID) {
+      memcpy (
+         (void *) (iter->raw + iter->d1), value->bytes, sizeof (value->bytes));
+   }
+}
+
+
+void
+bson_iter_overwrite_timestamp (bson_iter_t *iter,
+                               uint32_t timestamp,
+                               uint32_t increment)
+{
+   uint64_t value;
+   BSON_ASSERT (iter);
+
+   if (ITER_TYPE (iter) == BSON_TYPE_TIMESTAMP) {
+      value = ((((uint64_t) timestamp) << 32U) | ((uint64_t) increment));
+      value = BSON_UINT64_TO_LE (value);
+      memcpy ((void *) (iter->raw + iter->d1), &value, sizeof (value));
+   }
+}
+
+
+void
+bson_iter_overwrite_date_time (bson_iter_t *iter, int64_t value)
+{
+   BSON_ASSERT (iter);
+
+   if (ITER_TYPE (iter) == BSON_TYPE_DATE_TIME) {
+      value = BSON_UINT64_TO_LE (value);
+      memcpy ((void *) (iter->raw + iter->d1), &value, sizeof (value));
+   }
+}
+
+
 /*
  *--------------------------------------------------------------------------
  *

src/libbson/src/bson/bson-iter.h

@@ -521,6 +521,20 @@ BSON_EXPORT (void)
 bson_iter_overwrite_bool (bson_iter_t *iter, bool value);
 
 
+BSON_EXPORT (void)
+bson_iter_overwrite_oid (bson_iter_t *iter, const bson_oid_t *value);
+
+
+BSON_EXPORT (void)
+bson_iter_overwrite_timestamp (bson_iter_t *iter,
+                               uint32_t timestamp,
+                               uint32_t increment);
+
+
+BSON_EXPORT (void)
+bson_iter_overwrite_date_time (bson_iter_t *iter, int64_t value);
+
+
 BSON_EXPORT (bool)
 bson_iter_visit_all (bson_iter_t *iter,
                      const bson_visitor_t *visitor,

src/libbson/tests/test-iter.c

@@ -549,6 +549,60 @@ test_bson_iter_overwrite_bool (void)
 }
 
 
+static void
+test_bson_iter_overwrite_oid (void)
+{
+   bson_oid_t oid;
+   bson_iter_t iter;
+   bson_t b;
+
+   bson_oid_init_from_string (&oid, "000000000000000000001234");
+   bson_init (&b);
+   BSON_ASSERT (BSON_APPEND_OID (&b, "key", &oid));
+   BSON_ASSERT (bson_iter_init_find (&iter, &b, "key"));
+   bson_oid_init_from_string (&oid, "000000000000000000004321");
+   bson_iter_overwrite_oid (&iter, &oid);
+   BSON_ASSERT (bson_iter_init_find (&iter, &b, "key"));
+   ASSERT_CMPOID (bson_iter_oid (&iter), &oid);
+   bson_destroy (&b);
+}
+
+
+static void
+test_bson_iter_overwrite_timestamp (void)
+{
+   bson_iter_t iter;
+   bson_t b;
+   uint32_t t, i;
+
+   bson_init (&b);
+   BSON_ASSERT (BSON_APPEND_TIMESTAMP (&b, "key", 1, 2));
+   BSON_ASSERT (bson_iter_init_find (&iter, &b, "key"));
+   bson_iter_overwrite_timestamp (&iter, 3, 4);
+   BSON_ASSERT (bson_iter_init_find (&iter, &b, "key"));
+   bson_iter_timestamp (&iter, &t, &i);
+   ASSERT_CMPUINT32 (t, ==, 3);
+   ASSERT_CMPUINT32 (i, ==, 4);
+   bson_destroy (&b);
+}
+
+
+static void
+test_bson_iter_overwrite_date_time (void)
+{
+   bson_iter_t iter;
+   bson_t b;
+
+   bson_init (&b);
+   BSON_ASSERT (BSON_APPEND_DATE_TIME (&b, "key", 1234567890));
+   BSON_ASSERT (bson_iter_init_find (&iter, &b, "key"));
+   bson_iter_overwrite_date_time (&iter, -1234567890);
+   BSON_ASSERT (bson_iter_init_find (&iter, &b, "key"));
+   ASSERT_CMPINT64 (bson_iter_date_time (&iter), ==, -1234567890);
+   bson_destroy (&b);
+}
+
+
 static void
 test_bson_iter_recurse (void)
 {
@@ -699,6 +753,14 @@ test_iter_install (TestSuite *suite)
                   test_bson_iter_overwrite_double);
    TestSuite_Add (
       suite, "/bson/iter/test_overwrite_bool", test_bson_iter_overwrite_bool);
+   TestSuite_Add (
+      suite, "/bson/iter/test_overwrite_oid", test_bson_iter_overwrite_oid);
+   TestSuite_Add (suite,
+                  "/bson/iter/test_overwrite_timestamp",
+                  test_bson_iter_overwrite_timestamp);
+   TestSuite_Add (suite,
+                  "/bson/iter/test_overwrite_date_time",
+                  test_bson_iter_overwrite_date_time);
    TestSuite_Add (suite,
                   "/bson/iter/test_bson_iter_overwrite_decimal128",
                   test_bson_iter_overwrite_decimal128);