Adding error report to HBTree.

After a pwrite failure, I copy the errno value. It can then be queried
via JsonDbBtree::lastWriteError().
After a pread failure I do the same and the result can be queried via
JsonDbBtree::lastReadError().
I haven't modified AOB since I'm not familiar with it.

Change-Id: I76b6e7b4bbc2dd621eb716107a4e7a0aff38686c
Reviewed-by: Ali Akhtarzada <ali.akhtarzada@nokia.com>

4 files changed, 30 insertions, 4 deletions

diff --git a/src/hbtree/hbtree.cpp b/src/hbtree/hbtree.cpp
index 4c9ff2d..3d86392 100644
--- a/src/hbtree/hbtree.cpp
+++ b/src/hbtree/hbtree.cpp
@@ -44,6 +44,7 @@
 #include <sys/file.h>
 #include <sys/stat.h>
 #include <stddef.h>
+#include <errno.h>
 
 #include <QDebug>
 
@@ -95,7 +96,7 @@ HBtreePrivate::HBtreePrivate(HBtree *q, const QString &name)
     : q_ptr(q), fileName_(name), fd_(-1), openMode_(HBtree::ReadOnly), size_(0), lastSyncedId_(0), cacheSize_(20),
       compareFunction_(0),
       writeTransaction_(0), readTransaction_(0), lastPage_(PageInfo::INVALID_PAGE), cursorDisrupted_(false),
-      forceCommitFail_(0)
+      forceCommitFail_(0), lastWriteError_(0), lastReadError_(0)
 {
 }
 
@@ -154,6 +155,7 @@ bool HBtreePrivate::open(int fd)
             lastSyncedId_ = 0;
             size_ = initSize;
         } else {
+            lastReadError_ = errno;
             HBTREE_ERROR("failed to read spec page - rc:" << rc);
             return false;
         }
@@ -202,7 +204,7 @@ bool HBtreePrivate::open(int fd)
                  << ", residueHistory_:" << residueHistory_
                  << ", size_:" << size_
                  << "]");
-
+    lastReadError_ = 0;
     return true;
 }
 
@@ -265,9 +267,11 @@ bool HBtreePrivate::readSpec(const QByteArray &binaryData)
         int rc = pread(fd_, (void *)buffer.data(), spec.pageSize, 0);
 
         if (rc != spec.pageSize) {
+            lastReadError_ = errno;
             HBTREE_DEBUG("failed to read" << spec.pageSize << "bytes for spec page. Spec:" << spec);
             return false;
         }
+        lastReadError_ = 0;
     }
 
     quint32 crc = calculateChecksum(buffer);
@@ -730,9 +734,11 @@ QByteArray HBtreePrivate::readPage(quint32 pageNumber)
 
     ssize_t rc = read(fd_, (void *)pageBuffer_.data(), spec_.pageSize);
     if (rc != spec_.pageSize) {
+        lastReadError_ = errno;
         HBTREE_DEBUG("failed to read @" << offset << "for page" << pageNumber << "- rc:" << rc);
         return QByteArray();
     }
+    lastReadError_ = 0;
 
     PageInfo pageInfo = deserializePageInfo(pageBuffer_);
 
@@ -781,10 +787,11 @@ bool HBtreePrivate::writePage(QByteArray *buffer) const
     const off_t offset = pageNumber * spec_.pageSize;
     ssize_t rc = pwrite(fd_, (const void *)buffer->constData(), spec_.pageSize, offset);
     if (rc != spec_.pageSize) {
+        lastWriteError_ = errno;
         HBTREE_DEBUG("failed pwrite. Expected page size" << spec_.pageSize << "- rc:" << rc);
         return false;
     }
-
+    lastWriteError_ = 0;
     HBTREE_DEBUG("wrote page" << deserializePageInfo(*buffer));
 
     const Q_Q(HBtree);
@@ -2832,6 +2839,18 @@ bool HBtree::isOpen() const
     return d->fd_ != -1;
 }
 
+int HBtree::lastWriteError() const
+{
+    Q_D(const HBtree);
+    return d->lastWriteError_;
+}
+
+int HBtree::lastReadError() const
+{
+    Q_D(const HBtree);
+    return d->lastReadError_;
+}
+
 size_t HBtree::size() const
 {
     Q_D(const HBtree);
diff --git a/src/hbtree/hbtree.h b/src/hbtree/hbtree.h
index 997c5b1..f791404 100644
--- a/src/hbtree/hbtree.h
+++ b/src/hbtree/hbtree.h
@@ -134,6 +134,8 @@ public:
     bool open();
     void close();
     bool isOpen() const;
+    int lastWriteError() const;
+    int lastReadError() const;
 
     bool open(OpenMode mode) { setOpenMode(mode); return open(); }
 
diff --git a/src/hbtree/hbtree_p.h b/src/hbtree/hbtree_p.h
index c0efc4d..0686409 100644
--- a/src/hbtree/hbtree_p.h
+++ b/src/hbtree/hbtree_p.h
@@ -398,9 +398,10 @@ public:
     QList<Page *> lru_;
     bool cursorDisrupted_;
     mutable QByteArray pageBuffer_;
-
     bool verifyIntegrity(const Page *pPage) const;
     int forceCommitFail_;
+    mutable int lastWriteError_;
+    int lastReadError_;
 };
 
 QT_BEGIN_NAMESPACE
diff --git a/src/partition/jsondbbtree.h b/src/partition/jsondbbtree.h
index 6a64840..d05ffdc 100644
--- a/src/partition/jsondbbtree.h
+++ b/src/partition/jsondbbtree.h
@@ -119,6 +119,10 @@ public:
     Stat stats() const;
     bool sync()
     { Q_ASSERT(mBtree); return mBtree->sync(); }
+    int lastWriteError() const
+    { Q_ASSERT(mBtree); return mBtree->lastWriteError(); }
+    int lastReadError() const
+    { Q_ASSERT(mBtree); return mBtree->lastReadError(); }
 
     bool putOne(const QByteArray &key, const QByteArray &value);
     bool getOne(const QByteArray &key, QByteArray *value);