From 95801103c1fc773b074eea1b2d03820099ac09a6 Mon Sep 17 00:00:00 2001
From: Christian Mollekopf <chrigi_1@fastmail.fm>
Date: Wed, 10 Dec 2014 21:54:04 +0100
Subject: Storage: implemented scan

This can replace all our read calls. Note that we need a different API
for databases where the value needs to be loaded first, so we can do a key
scan before loading values. With this we can do key + value scans in one though.
---
 common/storage.h          |  4 ++++
 common/storage_common.cpp |  5 +++++
 common/storage_lmdb.cpp   | 14 +++++++++++---
 tests/storagetest.cpp     | 38 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/common/storage.h b/common/storage.h
index e5e592c..55688d4 100644
--- a/common/storage.h
+++ b/common/storage.h
@@ -34,6 +34,10 @@ public:
     void read(const std::string &sKey,
               const std::function<bool(void *ptr, int size)> & resultHandler,
               const std::function<void(const Storage::Error &error)> &errorHandler);
+    void scan(const std::string &sKey, const std::function<bool(void *keyPtr, int keySize, void *valuePtr, int valueSize)> &resultHandler);
+    void scan(const std::string &sKey,
+              const std::function<bool(void *keyPtr, int keySize, void *valuePtr, int valueSize)> & resultHandler,
+              const std::function<void(const Storage::Error &error)> &errorHandler);
 
     qint64 diskUsage() const;
     void removeFromDisk() const;
diff --git a/common/storage_common.cpp b/common/storage_common.cpp
index bc1acc4..246611c 100644
--- a/common/storage_common.cpp
+++ b/common/storage_common.cpp
@@ -19,3 +19,8 @@ void Storage::read(const std::string &sKey, const std::function<bool(void *ptr,
     read(sKey, resultHandler, &errorHandler);
 }
 
+void Storage::scan(const std::string &sKey, const std::function<bool(void *keyPtr, int keySize, void *valuePtr, int valueSize)> &resultHandler)
+{
+    scan(sKey, resultHandler, &errorHandler);
+}
+
diff --git a/common/storage_lmdb.cpp b/common/storage_lmdb.cpp
index b7102aa..95af3a2 100644
--- a/common/storage_lmdb.cpp
+++ b/common/storage_lmdb.cpp
@@ -210,6 +210,15 @@ void Storage::read(const std::string &sKey,
 void Storage::read(const std::string &sKey,
                    const std::function<bool(void *ptr, int size)> &resultHandler,
                    const std::function<void(const Storage::Error &error)> &errorHandler)
+{
+    scan(sKey, [resultHandler](void *keyPtr, int keySize, void *valuePtr, int valueSize) {
+        return resultHandler(valuePtr, valueSize);
+    }, errorHandler);
+}
+
+void Storage::scan(const std::string &sKey,
+                   const std::function<bool(void *keyPtr, int keySize, void *valuePtr, int valueSize)> &resultHandler,
+                   const std::function<void(const Storage::Error &error)> &errorHandler)
 {
     if (!d->env) {
         Error error(d->name.toStdString(), -1, "Not open");
@@ -243,10 +252,9 @@ void Storage::read(const std::string &sKey,
     }
 
     if (sKey.empty()) {
-        std::cout << "Iterating over all values of store!" << std::endl;
         rc = mdb_cursor_get(cursor, &key, &data, MDB_FIRST);
         while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
-            if (!resultHandler(key.mv_data, data.mv_size)) {
+            if (!resultHandler(key.mv_data, key.mv_size, data.mv_data, data.mv_size)) {
                 break;
             }
         }
@@ -257,7 +265,7 @@ void Storage::read(const std::string &sKey,
         }
     } else {
         if ((rc = mdb_cursor_get(cursor, &key, &data, MDB_SET)) == 0) {
-            resultHandler(data.mv_data, data.mv_size);
+            resultHandler(key.mv_data, key.mv_size, data.mv_data, data.mv_size);
         } else {
             std::cout << "couldn't find value " << sKey << " " << std::endl;
         }
diff --git a/tests/storagetest.cpp b/tests/storagetest.cpp
index 1974355..b3313c0 100644
--- a/tests/storagetest.cpp
+++ b/tests/storagetest.cpp
@@ -82,6 +82,44 @@ private Q_SLOTS:
         storage.removeFromDisk();
     }
 
+    void testScan()
+    {
+        const int count = 100;
+        populate(count);
+
+        //ensure we can scan for values
+        {
+            int hit = 0;
+            Storage store(testDataPath, dbName);
+            store.scan("", [&](void *keyValue, int keySize, void *dataValue, int dataSize) -> bool {
+                if (std::string(static_cast<char*>(keyValue), keySize) == "key50") {
+                    hit++;
+                }
+                return true;
+            });
+            QCOMPARE(hit, 1);
+        }
+
+        //ensure we can read a single value
+        {
+            int hit = 0;
+            bool foundInvalidValue = false;
+            Storage store(testDataPath, dbName);
+            store.scan("key50", [&](void *keyValue, int keySize, void *dataValue, int dataSize) -> bool {
+                if (std::string(static_cast<char*>(keyValue), keySize) != "key50") {
+                    foundInvalidValue = true;
+                }
+                hit++;
+                return true;
+            });
+            QVERIFY(!foundInvalidValue);
+            QCOMPARE(hit, 1);
+        }
+
+        Storage storage(testDataPath, dbName);
+        storage.removeFromDisk();
+    }
+
     void testConcurrentRead()
     {
         const int count = 10000;
-- 
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