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[libvirt] [libvirt-java] [PATCH] Fix wrapping of native size_t data type



Libvirt function parameters having type (pointer to) size_t were
wrapped via JNA using int, long or even NativeLong. Alas, none of
these is actually correct as the size of size_t may be the same as the
size of either (unsigned) int, long or even long long on different
platforms.

JNA provides the size of a native size_t to us, so using this
information we define and use class SizeT and class SizeTByReference for
wrapping a native size_t and size_t*, respectively.

Signed-off-by: Claudio Bley <cbley av-test de>
---
 src/main/java/org/libvirt/Domain.java              |    5 ++--
 src/main/java/org/libvirt/Secret.java              |   10 ++++----
 src/main/java/org/libvirt/Stream.java              |    7 +++--
 src/main/java/org/libvirt/jna/Libvirt.java         |   14 +++++-----
 src/main/java/org/libvirt/jna/SizeT.java           |   25 ++++++++++++++++++
 .../java/org/libvirt/jna/SizeTByReference.java     |   27 ++++++++++++++++++++
 6 files changed, 70 insertions(+), 18 deletions(-)
 create mode 100644 src/main/java/org/libvirt/jna/SizeT.java
 create mode 100644 src/main/java/org/libvirt/jna/SizeTByReference.java

diff --git a/src/main/java/org/libvirt/Domain.java b/src/main/java/org/libvirt/Domain.java
index a72e8c6..efac9b9 100644
--- a/src/main/java/org/libvirt/Domain.java
+++ b/src/main/java/org/libvirt/Domain.java
@@ -3,6 +3,7 @@ package org.libvirt;
 import org.libvirt.jna.DomainPointer;
 import org.libvirt.jna.DomainSnapshotPointer;
 import org.libvirt.jna.Libvirt;
+import org.libvirt.jna.SizeT;
 import org.libvirt.jna.virDomainBlockInfo;
 import org.libvirt.jna.virDomainBlockStats;
 import org.libvirt.jna.virDomainInfo;
@@ -234,7 +235,7 @@ public class Domain {
      */
     public DomainBlockStats blockStats(String path) throws LibvirtException {
         virDomainBlockStats stats = new virDomainBlockStats();
-        int success = libvirt.virDomainBlockStats(VDP, path, stats, stats.size());
+        int success = libvirt.virDomainBlockStats(VDP, path, stats, new SizeT(stats.size()));
         processError();
         return success == 0 ? new DomainBlockStats(stats) : null;
     }
@@ -695,7 +696,7 @@ public class Domain {
      */
     public DomainInterfaceStats interfaceStats(String path) throws LibvirtException {
         virDomainInterfaceStats stats = new virDomainInterfaceStats();
-        libvirt.virDomainInterfaceStats(VDP, path, stats, stats.size());
+        libvirt.virDomainInterfaceStats(VDP, path, stats, new SizeT(stats.size()));
         processError();
         return new DomainInterfaceStats(stats);
     }
diff --git a/src/main/java/org/libvirt/Secret.java b/src/main/java/org/libvirt/Secret.java
index 5332e02..4edb515 100644
--- a/src/main/java/org/libvirt/Secret.java
+++ b/src/main/java/org/libvirt/Secret.java
@@ -2,11 +2,11 @@ package org.libvirt;
 
 import org.libvirt.jna.Libvirt;
 import org.libvirt.jna.SecretPointer;
+import org.libvirt.jna.SizeT;
+import org.libvirt.jna.SizeTByReference;
 import static org.libvirt.Library.libvirt;
 
 import com.sun.jna.Native;
-import com.sun.jna.NativeLong;
-import com.sun.jna.ptr.LongByReference;
 import com.sun.jna.Pointer;
 import java.nio.ByteBuffer;
 
@@ -120,7 +120,7 @@ public class Secret {
      * @return the value of the secret, or null on failure.
      */
     public byte[] getByteValue() throws LibvirtException {
-        LongByReference value_size = new LongByReference();
+        SizeTByReference value_size = new SizeTByReference();
         Pointer value = libvirt.virSecretGetValue(VSP, value_size, 0);
         processError();
         ByteBuffer bb = value.getByteBuffer(0, value_size.getValue());
@@ -154,7 +154,7 @@ public class Secret {
      * @return 0 on success, -1 on failure.
      */
     public int setValue(String value) throws LibvirtException {
-        int returnValue = libvirt.virSecretSetValue(VSP, value, new NativeLong(value.length()), 0);
+        int returnValue = libvirt.virSecretSetValue(VSP, value, new SizeT(value.length()), 0);
         processError();
         return returnValue;
     }
@@ -165,7 +165,7 @@ public class Secret {
      * @return 0 on success, -1 on failure.
      */
     public int setValue(byte[] value) throws LibvirtException {
-        int returnValue = libvirt.virSecretSetValue(VSP, value, new NativeLong(value.length), 0);
+        int returnValue = libvirt.virSecretSetValue(VSP, value, new SizeT(value.length), 0);
         processError();
         return returnValue;
     }
diff --git a/src/main/java/org/libvirt/Stream.java b/src/main/java/org/libvirt/Stream.java
index 84e300c..d852d0d 100644
--- a/src/main/java/org/libvirt/Stream.java
+++ b/src/main/java/org/libvirt/Stream.java
@@ -1,11 +1,10 @@
 package org.libvirt;
 
 import org.libvirt.jna.Libvirt;
+import org.libvirt.jna.SizeT;
 import org.libvirt.jna.StreamPointer;
 import static org.libvirt.Library.libvirt;
 
-import com.sun.jna.NativeLong;
-
 public class Stream {
 
     public static int VIR_STREAM_NONBLOCK = (1 << 0);
@@ -108,7 +107,7 @@ public class Stream {
      * @throws LibvirtException
      */
     public int receive(byte[] data) throws LibvirtException {
-        int returnValue = libvirt.virStreamRecv(VSP, data, new NativeLong(data.length));
+        int returnValue = libvirt.virStreamRecv(VSP, data, new SizeT(data.length));
         processError();
         return returnValue;
     }
@@ -151,7 +150,7 @@ public class Stream {
      * @throws LibvirtException
      */
     public int send(String data) throws LibvirtException {
-        int returnValue = libvirt.virStreamSend(VSP, data, new NativeLong(data.length()));
+        int returnValue = libvirt.virStreamSend(VSP, data, new SizeT(data.length()));
         processError();
         return returnValue;
     }
diff --git a/src/main/java/org/libvirt/jna/Libvirt.java b/src/main/java/org/libvirt/jna/Libvirt.java
index 8c7d6ef..34ef966 100644
--- a/src/main/java/org/libvirt/jna/Libvirt.java
+++ b/src/main/java/org/libvirt/jna/Libvirt.java
@@ -180,7 +180,7 @@ public interface Libvirt extends Library {
     int virDomainAbortJob(DomainPointer virDomainPtr);
     int virDomainAttachDevice(DomainPointer virDomainPtr, String deviceXML);
     int virDomainAttachDeviceFlags(DomainPointer virDomainPtr, String deviceXML, int flags);
-    int virDomainBlockStats(DomainPointer virDomainPtr, String path, virDomainBlockStats stats, int size);
+    int virDomainBlockStats(DomainPointer virDomainPtr, String path, virDomainBlockStats stats, SizeT size);
     int virDomainBlockResize(DomainPointer virDomainPtr, String disk, long size, int flags);
     int virDomainCoreDump(DomainPointer virDomainPtr, String to, int flags);
     int virDomainCreate(DomainPointer virDomainPtr);
@@ -210,7 +210,7 @@ public interface Libvirt extends Library {
     Pointer virDomainGetXMLDesc(DomainPointer virDomainPtr, int flags);
     int virDomainHasCurrentSnapshot(DomainPointer virDomainPtr, int flags);
     int virDomainHasManagedSaveImage(DomainPointer virDomainPtr, int flags);
-    int virDomainInterfaceStats(DomainPointer virDomainPtr, String path, virDomainInterfaceStats stats, int size);
+    int virDomainInterfaceStats(DomainPointer virDomainPtr, String path, virDomainInterfaceStats stats, SizeT size);
     int virDomainIsActive(DomainPointer virDomainPtr);
     int virDomainIsPersistent(DomainPointer virDomainPtr);
     DomainPointer virDomainLookupByID(ConnectionPointer virConnectPtr, int id);
@@ -351,13 +351,13 @@ public interface Libvirt extends Library {
     int virSecretGetUUID(SecretPointer virSecretPtr, byte[] uuidString);
     int virSecretGetUUIDString(SecretPointer virSecretPtr, byte[] uuidString);
     String virSecretGetUsageID(SecretPointer virSecretPtr);
-    Pointer virSecretGetValue(SecretPointer virSecretPtr, LongByReference value_size, int flags);
+    Pointer virSecretGetValue(SecretPointer virSecretPtr, SizeTByReference value_size, int flags);
     String virSecretGetXMLDesc(SecretPointer virSecretPtr, int flags);
     SecretPointer virSecretLookupByUsage(ConnectionPointer virConnectPtr, int usageType, String usageID);
     SecretPointer virSecretLookupByUUID(ConnectionPointer virConnectPtr, byte[] uuidBytes);
     SecretPointer virSecretLookupByUUIDString(ConnectionPointer virConnectPtr, String uuidstr);
-    int virSecretSetValue(SecretPointer virSecretPtr, String value, NativeLong value_size, int flags);
-    int virSecretSetValue(SecretPointer virSecretPtr, byte[] value, NativeLong value_size, int flags);
+    int virSecretSetValue(SecretPointer virSecretPtr, String value, SizeT value_size, int flags);
+    int virSecretSetValue(SecretPointer virSecretPtr, byte[] value, SizeT value_size, int flags);
     int virSecretUndefine(SecretPointer virSecretPtr);
 
     //Stream Methods
@@ -369,9 +369,9 @@ public interface Libvirt extends Library {
     int virStreamFinish(StreamPointer virStreamPtr) ;
     int virStreamFree(StreamPointer virStreamPtr) ;
     StreamPointer virStreamNew(ConnectionPointer virConnectPtr, int flags) ;
-    int virStreamSend(StreamPointer virStreamPtr, String data, NativeLong size);
+    int virStreamSend(StreamPointer virStreamPtr, String data, SizeT size);
     int virStreamSendAll(StreamPointer virStreamPtr, Libvirt.VirStreamSourceFunc handler, Pointer opaque);
-    int virStreamRecv(StreamPointer virStreamPtr, byte[] data, NativeLong length);
+    int virStreamRecv(StreamPointer virStreamPtr, byte[] data, SizeT length);
     int virStreamRecvAll(StreamPointer virStreamPtr, Libvirt.VirStreamSinkFunc handler, Pointer opaque);
 
     //DomainSnapshot Methods
diff --git a/src/main/java/org/libvirt/jna/SizeT.java b/src/main/java/org/libvirt/jna/SizeT.java
new file mode 100644
index 0000000..298fe73
--- /dev/null
+++ b/src/main/java/org/libvirt/jna/SizeT.java
@@ -0,0 +1,25 @@
+package org.libvirt.jna;
+
+import com.sun.jna.Native;
+import com.sun.jna.IntegerType;
+
+/**
+ * Represents the native { code size_t} data type.
+ */
+public final class SizeT extends IntegerType {
+    public SizeT() { this(0); }
+    public SizeT(long value) {
+        /* N.B. A three argument constructor is supported starting with
+         * JNA version 3.4.1.
+         *
+         * The third argument determines whether this class represents
+         * an unsigned integer type. When extracting a value into a
+         * larger-sized container (e.g. 4 byte native type into Java
+         * long), the value is properly converted as unsigned.
+         *
+         * TODO: Use this constructor once we require JNA >= 3.4.1
+         */
+        // super(Native.SIZE_T_SIZE, value, true);
+        super(Native.SIZE_T_SIZE, value);
+    }
+}
diff --git a/src/main/java/org/libvirt/jna/SizeTByReference.java b/src/main/java/org/libvirt/jna/SizeTByReference.java
new file mode 100644
index 0000000..63fe453
--- /dev/null
+++ b/src/main/java/org/libvirt/jna/SizeTByReference.java
@@ -0,0 +1,27 @@
+package org.libvirt.jna;
+
+import com.sun.jna.Native;
+import com.sun.jna.ptr.ByReference;
+
+/**
+ * Represents a native (call-by-reference) pointer to { code size_t} data type.
+ */
+public final class SizeTByReference extends ByReference {
+    public SizeTByReference() {
+        this(0);
+    }
+    
+    public SizeTByReference(long value) {
+        super(Native.SIZE_T_SIZE);
+        setValue(value);
+    }
+    
+    public void setValue(long value) {
+        getPointer().setLong(0, value);
+    }
+    
+    public long getValue() {
+        return getPointer().getLong(0);
+    }
+    
+}
-- 
1.7.9.5


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