1 files changed, 304 insertions, 0 deletions
diff --git a/storage/FileSystemModule.cpp b/storage/FileSystemModule.cpp
new file mode 100644
index 000000000..ed2f8cdef
--- /dev/null
+++ b/storage/FileSystemModule.cpp
@@ -0,0 +1,304 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * 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 "FileSystemModule.h"
+
+#include "sqlite3.h"
+#include "nsString.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIFile.h"
+
+namespace {
+
+struct VirtualTableCursorBase
+{
+  VirtualTableCursorBase()
+  {
+    memset(&mBase, 0, sizeof(mBase));
+  }
+
+  sqlite3_vtab_cursor mBase;
+};
+
+struct VirtualTableCursor : public VirtualTableCursorBase
+{
+public:
+  VirtualTableCursor()
+  : mRowId(-1)
+  {
+    mCurrentFileName.SetIsVoid(true);
+  }
+
+  const nsString& DirectoryPath() const
+  {
+    return mDirectoryPath;
+  }
+
+  const nsString& CurrentFileName() const
+  {
+    return mCurrentFileName;
+  }
+
+  int64_t RowId() const
+  {
+    return mRowId;
+  }
+
+  nsresult Init(const nsAString& aPath);
+  nsresult NextFile();
+
+private:
+  nsCOMPtr<nsISimpleEnumerator> mEntries;
+
+  nsString mDirectoryPath;
+  nsString mCurrentFileName;
+
+  int64_t mRowId;
+};
+
+nsresult
+VirtualTableCursor::Init(const nsAString& aPath)
+{
+  nsCOMPtr<nsIFile> directory =
+    do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
+  NS_ENSURE_TRUE(directory, NS_ERROR_FAILURE);
+
+  nsresult rv = directory->InitWithPath(aPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = directory->GetPath(mDirectoryPath);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = directory->GetDirectoryEntries(getter_AddRefs(mEntries));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  rv = NextFile();
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult
+VirtualTableCursor::NextFile()
+{
+  bool hasMore;
+  nsresult rv = mEntries->HasMoreElements(&hasMore);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (!hasMore) {
+    mCurrentFileName.SetIsVoid(true);
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsISupports> entry;
+  rv = mEntries->GetNext(getter_AddRefs(entry));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIFile> file = do_QueryInterface(entry);
+  NS_ENSURE_TRUE(file, NS_ERROR_FAILURE);
+
+  rv = file->GetLeafName(mCurrentFileName);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mRowId++;
+
+  return NS_OK;
+}
+
+int Connect(sqlite3* aDB, void* aAux, int aArgc, const char* const* aArgv,
+            sqlite3_vtab** aVtab, char** aErr)
+{
+  static const char virtualTableSchema[] =
+    "CREATE TABLE fs ("
+      "name TEXT, "
+      "path TEXT"
+    ")";
+
+  int rc = sqlite3_declare_vtab(aDB, virtualTableSchema);
+  if (rc != SQLITE_OK) {
+    return rc;
+  }
+
+  sqlite3_vtab* vt = new sqlite3_vtab();
+  memset(vt, 0, sizeof(*vt));
+
+  *aVtab = vt;
+
+  return SQLITE_OK;
+}
+
+int Disconnect(sqlite3_vtab* aVtab )
+{
+  delete aVtab;
+
+  return SQLITE_OK;
+}
+
+int BestIndex(sqlite3_vtab* aVtab, sqlite3_index_info* aInfo)
+{
+  // Here we specify what index constraints we want to handle. That is, there
+  // might be some columns with particular constraints in which we can help
+  // SQLite narrow down the result set.
+  //
+  // For example, take the "path = x" where x is a directory. In this case,
+  // we can narrow our search to just this directory instead of the entire file
+  // system. This can be a significant optimization. So, we want to handle that
+  // constraint. To do so, we would look for two specific input conditions:
+  //
+  // 1. aInfo->aConstraint[i].iColumn == 1
+  // 2. aInfo->aConstraint[i].op == SQLITE_INDEX_CONSTRAINT_EQ
+  //
+  // The first states that the path column is being used in one of the input
+  // constraints and the second states that the constraint involves the equal
+  // operator.
+  //
+  // An even more specific search would be for name='xxx', in which case we
+  // can limit the search to a single file, if it exists.
+  //
+  // What we have to do here is look for all of our index searches and select
+  // the narrowest. We can only pick one, so obviously we want the one that
+  // is the most specific, which leads to the smallest result set.
+
+  for(int i = 0; i < aInfo->nConstraint; i++) {
+    if (aInfo->aConstraint[i].iColumn == 1 && aInfo->aConstraint[i].usable) {
+      if (aInfo->aConstraint[i].op & SQLITE_INDEX_CONSTRAINT_EQ) {
+        aInfo->aConstraintUsage[i].argvIndex = 1;
+      }
+      break;
+    }
+
+    // TODO: handle single files (constrained also by the name column)
+  }
+
+  return SQLITE_OK;
+}
+
+int Open(sqlite3_vtab* aVtab, sqlite3_vtab_cursor** aCursor)
+{
+  VirtualTableCursor* cursor = new VirtualTableCursor();
+
+  *aCursor = reinterpret_cast<sqlite3_vtab_cursor*>(cursor);
+
+  return SQLITE_OK;
+}
+
+int Close(sqlite3_vtab_cursor* aCursor)
+{
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  delete cursor;
+
+  return SQLITE_OK;
+}
+
+int Filter(sqlite3_vtab_cursor* aCursor, int aIdxNum, const char* aIdxStr,
+           int aArgc, sqlite3_value** aArgv)
+{
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  if(aArgc <= 0) {
+    return SQLITE_OK;
+  }
+
+  nsDependentString path(
+    reinterpret_cast<const char16_t*>(::sqlite3_value_text16(aArgv[0])));
+
+  nsresult rv = cursor->Init(path);
+  NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
+
+  return SQLITE_OK;
+}
+
+int Next(sqlite3_vtab_cursor* aCursor)
+{
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  nsresult rv = cursor->NextFile();
+  NS_ENSURE_SUCCESS(rv, SQLITE_ERROR);
+
+  return SQLITE_OK;
+}
+
+int Eof(sqlite3_vtab_cursor* aCursor)
+{
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+  return cursor->CurrentFileName().IsVoid() ? 1 : 0;
+}
+
+int Column(sqlite3_vtab_cursor* aCursor, sqlite3_context* aContext,
+           int aColumnIndex)
+{
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  switch (aColumnIndex) {
+    // name
+    case 0: {
+      const nsString& name = cursor->CurrentFileName();
+      sqlite3_result_text16(aContext, name.get(),
+                            name.Length() * sizeof(char16_t),
+                            SQLITE_TRANSIENT);
+      break;
+    }
+
+    // path
+    case 1: {
+      const nsString& path = cursor->DirectoryPath();
+      sqlite3_result_text16(aContext, path.get(),
+                            path.Length() * sizeof(char16_t),
+                            SQLITE_TRANSIENT);
+      break;
+    }
+    default:
+      NS_NOTREACHED("Unsupported column!");
+  }
+
+  return SQLITE_OK;
+}
+
+int RowId(sqlite3_vtab_cursor* aCursor, sqlite3_int64* aRowid)
+{
+  VirtualTableCursor* cursor = reinterpret_cast<VirtualTableCursor*>(aCursor);
+
+  *aRowid = cursor->RowId();
+
+  return SQLITE_OK;
+}
+
+} // namespace
+
+namespace mozilla {
+namespace storage {
+
+int RegisterFileSystemModule(sqlite3* aDB, const char* aName)
+{
+  static sqlite3_module module = {
+    1,
+    Connect,
+    Connect,
+    BestIndex,
+    Disconnect,
+    Disconnect,
+    Open,
+    Close,
+    Filter,
+    Next,
+    Eof,
+    Column,
+    RowId,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr,
+    nullptr
+  };
+
+  return sqlite3_create_module(aDB, aName, &module, nullptr);
+}
+
+} // namespace storage
+} // namespace mozilla