Fixed issue in GridStore seek and GridStore read to correctly work on…

… multiple seeks (Issue #895)
kothapalli · Mar 14, 2013 · 85d0f7d · 85d0f7d
1 parent 76bb1ae
commit 85d0f7d
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diff --git a/HISTORY b/HISTORY
@@ -9,6 +9,7 @@
 - Fixed issues related to node 0.10 and process.nextTick now correctly using setImmediate where needed on node 0.10
 - Added support for maxMessageSizeBytes if available (DRIVERS-1)
 - Added support for authSource (2.4) to MongoClient URL and db.authenticate method (DRIVER-69/NODE-34)
+- Fixed issue in GridStore seek and GridStore read to correctly work on multiple seeks (Issue #895)
 
 1.2.13 2013-02-22
 -----------------

diff --git a/lib/mongodb/gridfs/gridstore.js b/lib/mongodb/gridfs/gridstore.js
@@ -751,7 +751,7 @@ GridStore.prototype.read = function(length, buffer, callback) {
     // Copy content to final buffer
     slice.copy(finalBuffer, finalBuffer._index);
     // Update internal position
-    self.position = finalBuffer.length;
+    self.position = self.position + finalBuffer.length;
     // Check if we don't have a file at all
     if(finalLength == 0 && finalBuffer.length == 0) return callback(new Error("File does not exist"), null);
     // Else return data
@@ -818,6 +818,10 @@ GridStore.prototype.seek = function(position, seekLocation, callback) {
   var seekLocationFinal = seekLocation == null ? exports.GridStore.IO_SEEK_SET : seekLocation;
   var finalPosition = position;
   var targetPosition = 0;
+
+  // console.dir(targetPosition)
+
+  // Calculate the position
   if(seekLocationFinal == exports.GridStore.IO_SEEK_CUR) {
     targetPosition = self.position + finalPosition;
   } else if(seekLocationFinal == exports.GridStore.IO_SEEK_END) {
@@ -826,6 +830,7 @@ GridStore.prototype.seek = function(position, seekLocation, callback) {
     targetPosition = finalPosition;
   }
 
+  // Get the chunk
   var newChunkNumber = Math.floor(targetPosition/self.chunkSize);
   if(newChunkNumber != self.currentChunk.chunkNumber) {
     var seekChunk = function() {

diff --git a/test/tests/functional/gridstore/gridstore_tests.js b/test/tests/functional/gridstore/gridstore_tests.js
@@ -1845,6 +1845,84 @@ exports.shouldCorrectlyHandleSeekIntoSecondChunkWithStream = function(configurat
   });
 }
 
+/**
+ * @ignore
+ */
+exports['Should correctly handle multiple seeks'] = function(configuration, test) {
+  var GridStore = configuration.getMongoPackage().GridStore
+    , ObjectID = configuration.getMongoPackage().ObjectID;
+  var db = configuration.db();
+
+  var gridStore = new GridStore(db, "test_gs_seek_with_buffer", "w");
+  gridStore.open(function(err, gridStore) {
+    gridStore.write(new Buffer("012345678901234567890", "utf8"), function(err, gridStore) {
+      gridStore.close(function(result) {
+        var gridStore2 = new GridStore(db, "test_gs_seek_with_buffer", "r");
+        gridStore2.open(function(err, gridStore2) {
+
+          gridStore2.read( 5, function(err, data) {
+            test.equal("01234", data.toString());
+
+            gridStore2.seek(-2, GridStore.IO_SEEK_CUR, function(err, gridStore2) {
+
+              gridStore2.read( 5, function(err, data) {
+                test.equal("34567", data.toString());
+
+                gridStore2.seek(-2, GridStore.IO_SEEK_CUR, function(err, gridStore2) {
+
+                  gridStore2.read( 5, function(err, data) {
+                    test.equal("67890", data.toString());
+                    test.done();
+                  });
+                });
+              });
+            });
+          });
+        });
+      });
+    });
+  });
+}
+
+/**
+ * @ignore
+ */
+exports['Should correctly handle multiple seeks over several chunks'] = function(configuration, test) {
+  var GridStore = configuration.getMongoPackage().GridStore
+    , ObjectID = configuration.getMongoPackage().ObjectID;
+  var db = configuration.db();
+
+  var gridStore = new GridStore(db, "test_gs_seek_with_buffer", "w", {chunk_size:4});
+  gridStore.open(function(err, gridStore) {
+    gridStore.write(new Buffer("012345678901234567890", "utf8"), function(err, gridStore) {
+      gridStore.close(function(result) {
+        var gridStore2 = new GridStore(db, "test_gs_seek_with_buffer", "r");
+        gridStore2.open(function(err, gridStore2) {
+
+          gridStore2.read( 5, function(err, data) {
+            test.equal("01234", data.toString());
+
+            gridStore2.seek(-2, GridStore.IO_SEEK_CUR, function(err, gridStore2) {
+
+              gridStore2.read( 5, function(err, data) {
+                test.equal("34567", data.toString());
+
+                gridStore2.seek(-2, GridStore.IO_SEEK_CUR, function(err, gridStore2) {
+
+                  gridStore2.read( 5, function(err, data) {
+                    test.equal("67890", data.toString());
+                    test.done();
+                  });
+                });
+              });
+            });
+          });
+        });
+      });
+    });
+  });
+}
+
 /**
  * @ignore
  */