Implement chrome.experimental.downloads.search()

content/browser/download/download_query.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_QUERY_H_
+#define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_QUERY_H_
+#pragma once
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/stl_util.h"
+#include "content/browser/download/download_item.h"
+
+namespace download_util {
+
+// Filter and sort a vector of DownloadItem*s. See also the macros at the bottom
+// of this file.
+//
+// DownloadQuery query;
+// CHECK(query.Set("startTime", 0));

[asanka, 2011/10/20 19:29:16]

Nit: Field names aren't strings.

+// bool FilterOutOddDownloads(DownloadItem* item) {
+//   return 0 == (item->id() % 2);
+// }
+// CHECK(query.Set("filter", base::Bind(&FilterOutOddDownloads)));
+// CHECK(query.OrderBy("-startTime id error"));
+// query.Limit(20);
+// DownloadItems all_items, results;
+// query.Search(all_items.begin(), all_items.end(), &results);
+class DownloadQuery {
+ public:
+  typedef std::vector<DownloadItem*> DownloadItems;

[cbentzel, 2011/10/20 18:18:53]

Should this be DownloadItemInterface?

+
+  DownloadQuery();
+  ~DownloadQuery();
+
+  enum FilterFieldName {
+    FILTER_FIELD_BYTES_RECEIVED,
+    FILTER_FIELD_DANGER,
+    FILTER_FIELD_DANGER_ACCEPTED,
+    FILTER_FIELD_ENDED_AFTER,
+    FILTER_FIELD_ENDED_BEFORE,
+    FILTER_FIELD_END_TIME,
+    FILTER_FIELD_ERROR,
+    FILTER_FIELD_FILENAME,
+    FILTER_FIELD_FILENAME_REGEX,
+    FILTER_FIELD_FILE_SIZE,
+    FILTER_FIELD_FILE_SIZE_GREATER,
+    FILTER_FIELD_FILE_SIZE_LESS,
+    FILTER_FIELD_FILTER,
+    FILTER_FIELD_MIME,
+    FILTER_FIELD_PAUSED,
+    FILTER_FIELD_QUERY,
+    FILTER_FIELD_STARTED_AFTER,
+    FILTER_FIELD_STARTED_BEFORE,
+    FILTER_FIELD_START_TIME,
+    FILTER_FIELD_STATE,
+    FILTER_FIELD_TOTAL_BYTES,
+    FILTER_FIELD_TOTAL_BYTES_GREATER,
+    FILTER_FIELD_TOTAL_BYTES_LESS,
+    FILTER_FIELD_URL,
+    FILTER_FIELD_URL_REGEX,
+  };
+
+  // Returns false if |name| is unrecognized or if |value| is the wrong type or
+  // malformed. Returns true and sets the filter field named |name| to |value|
+  // otherwise. See the implementation for the type of each |name|. (DRY.)
+  template <typename ValueType>
+  bool Set(FilterFieldName name, const ValueType& value);
+
+  enum SortFieldName {
+    SORT_FIELD_BYTES_RECEIVED,
+    SORT_FIELD_DANGER,
+    SORT_FIELD_DANGER_ACCEPTED,
+    SORT_FIELD_END_TIME,
+    SORT_FIELD_ERROR,
+    SORT_FIELD_FILENAME,
+    SORT_FIELD_FILE_SIZE,
+    SORT_FIELD_MIME,
+    SORT_FIELD_PAUSED,
+    SORT_FIELD_START_TIME,
+    SORT_FIELD_STATE,
+    SORT_FIELD_TOTAL_BYTES,
+    SORT_FIELD_URL,
+  };
+
+  struct OrderTerm {
+    OrderTerm(SortFieldName field_name, bool ascending_)
+      : name(field_name),
+        ascending(ascending_) {
+    }
+    SortFieldName name;
+    bool ascending;
+  };
+  typedef std::vector<OrderTerm> OrderTerms;
+
+  // Copy |order_by| so that Search() can use it to sort results.
+  void OrderBy(const OrderTerms& order_by) {
+    order_by_fields_.assign(order_by.begin(), order_by.end());
+  }
+
+  // Remember to limit the size of search results to |limit|.
+  void Limit(uint32 limit) { limit_ = limit; }
+
+  // Filters DownloadItem*s from |iter| to |last| into |results|, sorts
+  // |results|, and limits the size of |results|. |results| must be non-NULL.
+  template <typename InputIterator>
+  void Search(InputIterator iter, const InputIterator last,
+              DownloadItems* results) const;
+
+  // Returns true if |item| matches all set filter fields; returns false if any
+  // filter fields have been set that the item does not match.
+  bool Matches(const DownloadItem& item) const;
+
+  // Ignore these mostly-private interfaces.
+  class SortFieldInterface;
+  class FilterFieldInterface;
+  typedef std::map<SortFieldName, SortFieldInterface*> SortFields;
+  typedef std::map<FilterFieldName, FilterFieldInterface*> FilterFields;
+
+ private:
+  void SetSortField(SortFieldName name, SortFieldInterface* field);
+  void SetFilterField(FilterFieldName name, FilterFieldInterface* field);
+
+  SortFields sort_fields_;
+  FilterFields filter_fields_;
+  OrderTerms order_by_fields_;
+  uint32 limit_;
+  STLValueDeleter<SortFields> delete_sort_fields_;
+  STLValueDeleter<FilterFields> delete_filter_fields_;
+
+  DISALLOW_COPY_AND_ASSIGN(DownloadQuery);
+};
+}  // namespace download_util
+
+
+// The following macros facilitate using anonymous expressions (lambdas) to
+// implement arbitrary filters for DownloadQuery. The parameters passed to the
+// second and third forms MUST be variable names and cannot be expressions or
+// even lvalues.
+//
+// query.Set("filter", DOWNLOAD_QUERY_FILTER2(otr, foo,

[asanka, 2011/10/20 19:29:16]

Nit: Field name isn't a string.

+//   item.otr() == otr && item.foo() == foo));
+
+#define SYMCAT(X, Y) X##Y
+#define DOWNLOAD_QUERY_FILTER_IMPL(NAME, expr) \
+  ({struct NAME {static bool Filter(const DownloadItem& item) {return expr;}}; \
+    base::Bind(&NAME::Filter);})
+#define DOWNLOAD_QUERY_FILTER1_IMPL(NAME, var0, expr) \
+  ({template<typename Var0Type>struct NAME {static bool Filter( \
+      Var0Type var0, const DownloadItem& item) {return expr;}}; \
+    base::Bind(&NAME::Filter, var0);})
+#define DOWNLOAD_QUERY_FILTER2_IMPL(NAME, var0, var1, expr) \
+  ({template<typename Var0Type, Var1Type>struct NAME {static bool Filter( \
+      Var0Type var0, Var1Type var1, const DownloadItem& item) {return expr;}}; \
+    base::Bind(&NAME::Filter, var0, var1);})
+#define DOWNLOAD_QUERY_FILTER(expr) DOWNLOAD_QUERY_FILTER_IMPL( \
+  SYMCAT(DownloadQueryFilter, __LINE__), (expr))
+#define DOWNLOAD_QUERY_FILTER1(var0, expr) DOWNLOAD_QUERY_FILTER1_IMPL( \
+  SYMCAT(DownloadQueryFilter, __LINE__), var0, (expr))
+#define DOWNLOAD_QUERY_FILTER2(var0, var1, expr) DOWNLOAD_QUERY_FILTER2_IMPL( \
+  SYMCAT(DownloadQueryFilter, __LINE__), var0, var1, (expr))
+
+#endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_QUERY_H_