intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 66 insertions, 0 deletions

diff --git a/library/cpp/yson_pull/read_ops.cpp b/library/cpp/yson_pull/read_ops.cpp
new file mode 100644
index 0000000000..9d7e6a4a2d
--- /dev/null
+++ b/library/cpp/yson_pull/read_ops.cpp
@@ -0,0 +1,66 @@
+#include "read_ops.h"
+
+using namespace NYsonPull;
+using namespace NYsonPull::NReadOps;
+
+namespace {
+    bool TrySkipValueUntil(EEventType end, TReader& reader) {
+        const auto& event = reader.NextEvent();
+        if (event.Type() == end) {
+            return false;
+        }
+        SkipCurrentValue(event, reader);
+        return true;
+    }
+
+    bool TrySkipKeyValueUntil(EEventType end, TReader& reader) {
+        const auto& event = reader.NextEvent();
+        if (event.Type() == end) {
+            return false;
+        }
+        Expect(event, EEventType::Key);
+        SkipValue(reader);
+        return true;
+    }
+}
+
+void NYsonPull::NReadOps::SkipCurrentValue(const TEvent& event, TReader& reader) {
+    switch (event.Type()) {
+        case EEventType::BeginList:
+            while (TrySkipValueUntil(EEventType::EndList, reader)) {
+            }
+            return;
+
+        case EEventType::BeginMap:
+            while (TrySkipKeyValueUntil(EEventType::EndMap, reader)) {
+            }
+            return;
+
+        case EEventType::BeginAttributes:
+            while (TrySkipKeyValueUntil(EEventType::EndAttributes, reader)) {
+            }
+            // attributes after attributes are disallowed in TReader
+            SkipValue(reader);
+            return;
+
+        case EEventType::Scalar:
+            return;
+
+        default:
+            throw yexception() << "Unexpected event: " << event;
+    }
+}
+
+void NYsonPull::NReadOps::SkipValue(TReader& reader) {
+    const auto& event = reader.NextEvent();
+    SkipCurrentValue(event, reader);
+}
+
+void NYsonPull::NReadOps::SkipControlRecords(TReader& reader) {
+    const auto* event = &reader.LastEvent();
+    while (event->Type() == EEventType::BeginAttributes) {
+        SkipCurrentValue(*event, reader);
+        event = &reader.NextEvent();
+    }
+    Expect(*event, EEventType::BeginMap);
+}