Implement query translation from GData WAPI to Drive API v2.

chrome/browser/google_apis/drive_api_service.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/google_apis/drive_api_service.h"
 
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/message_loop_proxy.h"
+#include "base/string16.h"
 #include "base/string_util.h"
 #include "base/stringprintf.h"
 #include "base/task_runner_util.h"
 #include "base/threading/sequenced_worker_pool.h"
+#include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/google_apis/auth_service.h"
 #include "chrome/browser/google_apis/drive_api_operations.h"
 #include "chrome/browser/google_apis/drive_api_parser.h"
 #include "chrome/browser/google_apis/gdata_wapi_operations.h"
 #include "chrome/browser/google_apis/gdata_wapi_parser.h"
 #include "chrome/browser/google_apis/operation_runner.h"
 #include "chrome/browser/google_apis/time_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 176 matching lines @@
 }
 
 // It is necessary to escape ' to \' in the query's string value.
 // See also: https://developers.google.com/drive/search-parameters
 std::string EscapeQueryStringValue(const std::string& str) {
   std::string result;
   ReplaceChars(str, "'", "\\'", &result);
   return result;
 }
 
+// Parses the query, and builds a search query for Drive API v2.
+// This only supports:
+//   Regular query (e.g. dog).
+//   Conjunctions (e.g. dog cat).
+//   Exclusion query (e.g. -cat).

[hashimoto, 2013/04/18 07:23:50]

Please add output examples.

[hidehiko, 2013/04/18 09:04:32]

Done.

+//   Quoted query (e.g. "dog cat").

[kinaba, 2013/04/18 06:59:48]

Could you add the URLs for the search syntax of two APIs as a comment?

[hidehiko, 2013/04/18 09:04:32]

Done.

+std::string TranslateQuery(const std::string& original_query) {

[hashimoto, 2013/04/18 07:23:50]

Can't we have a test for this function or DriveAPIService::Search?

[hidehiko, 2013/04/18 09:04:32]

Done.

+  base::string16 query = UTF8ToUTF16(original_query);

[hashimoto, 2013/04/18 07:23:50]

Why do we need to convert the string to UTF16, not using UTF8 directly or using
UTF8ToWide?

[hidehiko, 2013/04/18 09:04:32]

To handle non-ascii white space correctly. Added comments.

+  const base::string16 kDelimiter(
+      kWhitespaceUTF16 + base::string16(1, static_cast<char16>('"')));
+
+  std::string result;
+  for (size_t index = query.find_first_not_of(kWhitespaceUTF16);
+       index != base::string16::npos;
+       index = query.find_first_not_of(kWhitespaceUTF16, index)) {
+    bool is_exclusion = false;
+    size_t begin_token = index;
+    base::string16 token;
+    if (query[begin_token] == '"') {
+      // Quoted query.
+      ++begin_token;
+      size_t end_token = query.find('"', begin_token);
+      if (end_token == base::string16::npos) {
+        // This is kind of syntax error, since quoted string isn't finished.
+        // However, the query is built by user manually, so here we treat
+        // whole remaining string as a token as a fallback.

[kinaba, 2013/04/18 06:59:48]

How about:
end_token = query.length();
query += '"';

and share the "token = ...; index = ...;" part with the correct case.
I remember discussion with you about npos, but I'm still worrying :).
Future reader might feel anxious as well about passing npos.

[hidehiko, 2013/04/18 09:04:32]

Indeed. Done.

+        token = query.substr(begin_token);
+        index = base::string16::npos;
+      } else {
+        token = query.substr(begin_token, end_token - begin_token);
+        index = (end_token + 1);  // Consume last '"', too.
+      }
+    } else {
+      size_t end_token = query.find_first_of(kDelimiter, begin_token);
+      if (end_token == base::string16::npos) {
+        end_token = query.length();
+      }
+
+      if (query[begin_token] == '-' && end_token > begin_token + 1) {
+        // This is an exclusion query token.
+        is_exclusion = true;
+        ++begin_token;
+      }
+
+      token = query.substr(begin_token, end_token - begin_token);
+      index = end_token;
+    }
+
+    if (!result.empty()) {
+      // If there are two or more tokens, need to connect with "and".
+      result.append(" and ");
+    }
+
+    base::StringAppendF(

[kinaba, 2013/04/18 06:59:48]

Please add comment on what "fullText" includes, like
https://code.google.com/p/chromium/issues/detail?id=232352#c5.

[hidehiko, 2013/04/18 09:04:32]

Done.

+        &result,
+        "%sfullText contains \'%s\'",
+        is_exclusion ? "not " : "",
+        EscapeQueryStringValue(UTF16ToUTF8(token)).c_str());
+  }
+
+  return result;
+}
+
 // The resource ID for the root directory for Drive API is defined in the spec:
 // https://developers.google.com/drive/folder
 const char kDriveApiRootDirectoryResourceId[] = "root";
 
 }  // namespace
 
 DriveAPIService::DriveAPIService(
     net::URLRequestContextGetter* url_request_context_getter,
     const GURL& base_url,
     const GURL& wapi_base_url,
@@ skipping 113 matching lines @@
                              const GetResourceListCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!search_query.empty());
   DCHECK(!callback.is_null());
 
   runner_->StartOperationWithRetry(
       new GetFilelistOperation(
           operation_registry(),
           url_request_context_getter_,
           url_generator_,
-          search_query,
+          TranslateQuery(search_query),
           base::Bind(&ParseResourceListOnBlockingPoolAndRun, callback)));
 }
 
 void DriveAPIService::SearchInDirectory(
     const std::string& search_query,
     const std::string& directory_resource_id,
     const GetResourceListCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!search_query.empty());
   DCHECK(!directory_resource_id.empty());
@@ skipping 362 matching lines @@
 }
 
 void DriveAPIService::OnProgressUpdate(
     const OperationProgressStatusList& list) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   FOR_EACH_OBSERVER(
       DriveServiceObserver, observers_, OnProgressUpdate(list));
 }
 
 }  // namespace google_apis