Implement query translation from GData WAPI to Drive API v2.

chrome/browser/google_apis/drive_api_util.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_util.h"
 
 #include "base/command_line.h"
+#include "base/string16.h"
 #include "base/string_util.h"
+#include "base/stringprintf.h"
+#include "base/utf_string_conversions.h"
 #include "chrome/browser/google_apis/drive_switches.h"
 
 namespace google_apis {
 namespace util {
 
 bool IsDriveV2ApiEnabled() {
   return CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableDriveV2Api);
 }
 
 }  // namespace util
 
 namespace drive {
 namespace util {
 
 std::string EscapeQueryStringValue(const std::string& str) {
   std::string result;
   ReplaceChars(str, "'", "\\'", &result);
   return result;
 }
 
+std::string TranslateQuery(const std::string& original_query) {
+  // In order to handle non-ascii white spaces correctly, convert to UTF16.
+  base::string16 query = UTF8ToUTF16(original_query);
+  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 = (query[index] == '-');
+    if (is_exclusion)
+      ++index;
+    if (index == query.length()) {
+      // Here, the token is '-' and it should be ignored.
+      continue;
+    }
+
+    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, by appending
+        // a missing double-quote character.
+        end_token = query.length();
+        query.push_back('"');
+      }
+
+      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();
+      }
+
+      token = query.substr(begin_token, end_token - begin_token);
+      index = end_token;
+    }
+
+    if (token.empty()) {
+      // Just ignore an empty token.
+      continue;
+    }
+
+    if (!result.empty()) {
+      // If there are two or more tokens, need to connect with "and".
+      result.append(" and ");
+    }
+
+    // The meaning of "fullText" should include title, description and content.
+    base::StringAppendF(
+        &result,
+        "%sfullText contains \'%s\'",
+        is_exclusion ? "not " : "",
+        EscapeQueryStringValue(UTF16ToUTF8(token)).c_str());
+  }
+
+  return result;
+}
+
 }  // namespace util
 }  // namespace drive
 }  // namespace google_apis