Add FacadeTest

Facade.h

@@ -0,0 +1,167 @@
+#pragma once
+
+#include "VersionedMap.h"
+
+#include <assert.h>
+#include <map>
+#include <string>
+
+using String = std::basic_string<uint8_t>;
+
+struct Facade {
+
+  explicit Facade(int64_t version) : versioned{version} {}
+
+  struct View {
+
+    std::vector<std::pair<String, String>> rangeRead(const String &begin,
+                                                     const String &end,
+                                                     int limit,
+                                                     bool reverse) const {
+      std::vector<std::pair<String, String>> result;
+      weaselab::VersionedMap::Iterator versionedIter[2];
+      const weaselab::VersionedMap::Key key[] = {
+          {begin.data(), int(begin.size())}, {end.data(), int(end.size())}};
+      const int64_t v[] = {version, version};
+      facade->versioned.firstGeq(key, v, versionedIter, 2);
+
+      const uint8_t zero[] = {0};
+      if (reverse) {
+        weaselab::VersionedMap::Iterator iter = versionedIter[1];
+        weaselab::VersionedMap::Iterator endIter = versionedIter[0];
+        String readUntil = end;
+        for (; iter != endIter; --iter) {
+          auto m = *iter;
+          auto mEnd = m.type == weaselab::VersionedMap::Set
+                          ? String(m.param1, m.param1Len) + String(zero, 1)
+                          : String(m.param2, m.param2Len);
+          auto remaining =
+              facade->unversionedRead(mEnd, readUntil, limit, true);
+          result.insert(result.end(), remaining.begin(), remaining.end());
+          if (limit == 0) {
+            return result;
+          }
+          switch (m.type) {
+          case weaselab::VersionedMap::Set: {
+            result.push_back(
+                {String(m.param1, m.param1Len), String(m.param2, m.param2Len)});
+            --limit;
+            if (limit == 0) {
+              return result;
+            }
+            readUntil = String(m.param1, m.param1Len);
+          } break;
+          case weaselab::VersionedMap::Clear:
+            readUntil = String(m.param1, m.param1Len);
+            break;
+          }
+        }
+        auto remaining = facade->unversionedRead(begin, readUntil, limit, true);
+        result.insert(result.end(), remaining.begin(), remaining.end());
+        return result;
+      } else {
+        weaselab::VersionedMap::Iterator iter = versionedIter[0];
+        weaselab::VersionedMap::Iterator endIter = versionedIter[1];
+        String readThrough = begin;
+        for (; iter != endIter; ++iter) {
+          auto m = *iter;
+          auto remaining = facade->unversionedRead(
+              readThrough, String(m.param1, m.param1Len), limit, false);
+          result.insert(result.end(), remaining.begin(), remaining.end());
+          if (limit == 0) {
+            return result;
+          }
+          switch (m.type) {
+          case weaselab::VersionedMap::Set: {
+            result.push_back(
+                {String(m.param1, m.param1Len), String(m.param2, m.param2Len)});
+            --limit;
+            if (limit == 0) {
+              return result;
+            }
+            uint8_t zero[] = {0};
+            readThrough = String(m.param1, m.param1Len) + String(zero, 1);
+          } break;
+          case weaselab::VersionedMap::Clear:
+            readThrough = String(m.param2, m.param2Len);
+            break;
+          }
+        }
+        auto remaining =
+            facade->unversionedRead(readThrough, end, limit, false);
+        result.insert(result.end(), remaining.begin(), remaining.end());
+        return result;
+      }
+    }
+
+    /** @private */
+    View(const Facade *facade, int64_t version)
+        : facade{facade}, version{version} {}
+
+  private:
+    const Facade *facade;
+    int64_t version;
+  };
+
+  void addMutations(const weaselab::VersionedMap::Mutation *mutations,
+                    int numMutations, int64_t version) {
+    versioned.addMutations(mutations, numMutations, version);
+  }
+
+  void setOldestVersion(int64_t version) {
+    for (auto iter = versioned.begin(version), end = versioned.end(version);
+         iter != end; ++iter) {
+      auto m = *iter;
+      switch (m.type) {
+      case weaselab::VersionedMap::Set:
+        unversioned[String(m.param1, m.param1Len)] =
+            String(m.param2, m.param2Len);
+        break;
+      case weaselab::VersionedMap::Clear:
+        for (auto unversionedIter =
+                 unversioned.lower_bound(String(m.param1, m.param1Len));
+             unversionedIter != unversioned.end() &&
+             unversionedIter->first < String(m.param2, m.param2Len);) {
+          unversionedIter = unversioned.erase(unversionedIter);
+        }
+        break;
+      }
+    }
+
+    versioned.setOldestVersion(version);
+  }
+
+  View viewAt(int64_t version) const { return View{this, version}; }
+
+  int64_t getVersion() const { return versioned.getVersion(); }
+  int64_t getOldestVersion() const { return versioned.getOldestVersion(); }
+
+private:
+  std::vector<std::pair<String, String>> unversionedRead(const String &begin,
+                                                         const String &end,
+                                                         int &limit,
+                                                         bool reverse) const {
+    std::vector<std::pair<String, String>> result;
+    if (reverse) {
+      if (unversioned.empty()) {
+        return result;
+      }
+      for (auto iter = --unversioned.lower_bound(end);
+           iter->first >= begin && limit > 0; --iter) {
+        result.push_back(*iter);
+        --limit;
+      }
+    } else {
+      for (auto iter = unversioned.lower_bound(begin),
+                iterEnd = unversioned.lower_bound(end);
+           iter != iterEnd && limit > 0; ++iter) {
+        result.push_back(*iter);
+        --limit;
+      }
+    }
+    return result;
+  }
+
+  std::map<String, String> unversioned;
+  weaselab::VersionedMap versioned;
+};