1 files changed, 106 insertions, 0 deletions
diff --git a/comm/mailnews/extensions/fts3/nsGlodaRankerFunction.cpp b/comm/mailnews/extensions/fts3/nsGlodaRankerFunction.cpp
new file mode 100644
index 0000000000..9ba125466f
--- /dev/null
+++ b/comm/mailnews/extensions/fts3/nsGlodaRankerFunction.cpp
@@ -0,0 +1,106 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsGlodaRankerFunction.h"
+#include "mozIStorageValueArray.h"
+
+#include "sqlite3.h"
+
+#include "nsCOMPtr.h"
+#include "nsVariant.h"
+#include "nsComponentManagerUtils.h"
+
+#ifndef SQLITE_VERSION_NUMBER
+#  error "We need SQLITE_VERSION_NUMBER defined!"
+#endif
+
+NS_IMPL_ISUPPORTS(nsGlodaRankerFunction, mozIStorageFunction)
+
+nsGlodaRankerFunction::nsGlodaRankerFunction() {}
+
+nsGlodaRankerFunction::~nsGlodaRankerFunction() {}
+
+static uint32_t COLUMN_SATURATION[] = {10, 1, 1, 1, 1};
+
+/**
+ * Our ranking function basically just multiplies the weight of the column
+ * against the number of (saturating) matches.
+ *
+ * The original code is a SQLite example ranking function, although somewhat
+ * rather modified at this point.  All SQLite code is public domain, so we are
+ * subsuming it to MPL1.1/LGPL2/GPL2.
+ */
+NS_IMETHODIMP
+nsGlodaRankerFunction::OnFunctionCall(mozIStorageValueArray* aArguments,
+                                      nsIVariant** _result) {
+  // all argument names are maintained from the original SQLite code.
+  uint32_t nVal;
+  nsresult rv = aArguments->GetNumEntries(&nVal);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  /* Check that the number of arguments passed to this function is correct.
+   * If not, return an error. Set aArgsData to point to the array
+   * of unsigned integer values returned by FTS3 function. Set nPhrase
+   * to contain the number of reportable phrases in the users full-text
+   * query, and nCol to the number of columns in the table.
+   */
+  if (nVal < 1) return NS_ERROR_INVALID_ARG;
+
+  uint32_t lenArgsData;
+  uint32_t* aArgsData = (uint32_t*)aArguments->AsSharedBlob(0, &lenArgsData);
+
+  uint32_t nPhrase = aArgsData[0];
+  uint32_t nCol = aArgsData[1];
+  if (nVal != (1 + nCol)) return NS_ERROR_INVALID_ARG;
+
+  double score = 0.0;
+
+  // SQLite 3.6.22 has a different matchinfo layout than SQLite 3.6.23+
+#if SQLITE_VERSION_NUMBER <= 3006022
+  /* Iterate through each phrase in the users query. */
+  for (uint32_t iPhrase = 0; iPhrase < nPhrase; iPhrase++) {
+    // in SQ
+    for (uint32_t iCol = 0; iCol < nCol; iCol++) {
+      uint32_t nHitCount = aArgsData[2 + (iPhrase + 1) * nCol + iCol];
+      double weight = aArguments->AsDouble(iCol + 1);
+      if (nHitCount > 0) {
+        score += (nHitCount > COLUMN_SATURATION[iCol])
+                     ? (COLUMN_SATURATION[iCol] * weight)
+                     : (nHitCount * weight);
+      }
+    }
+  }
+#else
+  /* Iterate through each phrase in the users query. */
+  for (uint32_t iPhrase = 0; iPhrase < nPhrase; iPhrase++) {
+    /* Now iterate through each column in the users query. For each column,
+    ** increment the relevancy score by:
+    **
+    **   (<hit count> / <global hit count>) * <column weight>
+    **
+    ** aPhraseinfo[] points to the start of the data for phrase iPhrase. So
+    ** the hit count and global hit counts for each column are found in
+    ** aPhraseinfo[iCol*3] and aPhraseinfo[iCol*3+1], respectively.
+    */
+    uint32_t* aPhraseinfo = &aArgsData[2 + iPhrase * nCol * 3];
+    for (uint32_t iCol = 0; iCol < nCol; iCol++) {
+      uint32_t nHitCount = aPhraseinfo[3 * iCol];
+      double weight = aArguments->AsDouble(iCol + 1);
+      if (nHitCount > 0) {
+        score += (nHitCount > COLUMN_SATURATION[iCol])
+                     ? (COLUMN_SATURATION[iCol] * weight)
+                     : (nHitCount * weight);
+      }
+    }
+  }
+#endif
+
+  nsCOMPtr<nsIWritableVariant> result = new nsVariant();
+
+  rv = result->SetAsDouble(score);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  result.forget(_result);
+  return NS_OK;
+}