Print Preview: Go from event driven print preview back to print preview with sync messages. The s...

chrome/browser/ui/webui/print_preview_ui.cc

 // 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.
 
 #include "chrome/browser/ui/webui/print_preview_ui.h"
 
+#include <map>
+
+#include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
+#include "base/synchronization/lock.h"
 #include "base/values.h"
 #include "chrome/browser/printing/print_preview_data_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/print_preview_data_source.h"
 #include "chrome/browser/ui/webui/print_preview_handler.h"
 #include "chrome/common/print_messages.h"
 #include "content/browser/tab_contents/tab_contents.h"
+#include "printing/print_job_constants.h"
+
+namespace {
+
+// Thread-safe wrapper around a std::map to keep track of mappings from
+// PrintPreviewUI addresses to most recent print preview request ids.
+class PrintPreviewRequestIdMapWithLock {
+ public:
+  PrintPreviewRequestIdMapWithLock() {}
+  ~PrintPreviewRequestIdMapWithLock() {}
+
+  // Get the value for |addr|. Returns true and sets |out_value| on success.
+  bool Get(const std::string& addr, int* out_value) {
+    base::AutoLock lock(lock_);
+    PrintPreviewRequestIdMap::const_iterator it = map_.find(addr);
+    if (it == map_.end())
+      return false;
+    *out_value = it->second;
+    return true;
+  }
+
+  // Sets the |value| for |addr|.
+  void Set(const std::string& addr, int value) {
+    base::AutoLock lock(lock_);
+    map_[addr] = value;
+  }
+
+  // Erase the entry for |addr|.
+  void Erase(const std::string& addr) {
+    base::AutoLock lock(lock_);
+    map_.erase(addr);
+  }
+
+ private:
+  typedef std::map<std::string, int> PrintPreviewRequestIdMap;
+
+  PrintPreviewRequestIdMap map_;
+  base::Lock lock_;
+};
+
+// Written to on the UI thread, read from any thread.
+base::LazyInstance<PrintPreviewRequestIdMapWithLock>
+    g_print_preview_request_id_map(base::LINKER_INITIALIZED);
+
+}  // namespace
 
 PrintPreviewUI::PrintPreviewUI(TabContents* contents)
     : ChromeWebUI(contents),
-      initial_preview_start_time_(base::TimeTicks::Now()),
-      request_count_(0U),
-      document_cookie_(0) {
+      initial_preview_start_time_(base::TimeTicks::Now()) {
   // WebUI owns |handler_|.
   handler_ = new PrintPreviewHandler();
   AddMessageHandler(handler_->Attach(this));
 
   // Set up the chrome://print/ data source.
   Profile* profile = Profile::FromBrowserContext(contents->browser_context());
   profile->GetChromeURLDataManager()->AddDataSource(
       new PrintPreviewDataSource());
 
-  // Store the PrintPreviewUIAddress as a string.
-  // "0x" + deadc0de + '\0' = 2 + 2 * sizeof(this) + 1;
-  char preview_ui_addr[2 + (2 * sizeof(this)) + 1];
-  base::snprintf(preview_ui_addr, sizeof(preview_ui_addr), "%p", this);
-  preview_ui_addr_str_ = preview_ui_addr;
+  preview_ui_addr_str_ = GetPrintPreviewUIAddress();
+
+  g_print_preview_request_id_map.Get().Set(preview_ui_addr_str_, -1);
 }
 
 PrintPreviewUI::~PrintPreviewUI() {
   print_preview_data_service()->RemoveEntry(preview_ui_addr_str_);
+
+  g_print_preview_request_id_map.Get().Erase(preview_ui_addr_str_);
 }
 
 void PrintPreviewUI::GetPrintPreviewDataForIndex(
     int index,
     scoped_refptr<RefCountedBytes>* data) {
   print_preview_data_service()->GetDataEntry(preview_ui_addr_str_, index, data);
 }
 
 void PrintPreviewUI::SetPrintPreviewDataForIndex(int index,
                                                  const RefCountedBytes* data) {
   print_preview_data_service()->SetDataEntry(preview_ui_addr_str_, index, data);
 }
 
 void PrintPreviewUI::ClearAllPreviewData() {
   print_preview_data_service()->RemoveEntry(preview_ui_addr_str_);
 }
 
 void PrintPreviewUI::SetInitiatorTabURLAndTitle(
     const std::string& initiator_url,
     const string16& job_title) {
   initiator_url_ = initiator_url;
   initiator_tab_title_ = job_title;
 }
 
+// static
+void PrintPreviewUI::GetCurrentPrintPreviewStatus(
+    const std::string& preview_ui_addr,
+    int request_id,
+    bool* cancel) {
+  int current_id = -1;
+  if (!g_print_preview_request_id_map.Get().Get(preview_ui_addr, &current_id)) {
+    *cancel = true;
+    return;
+  }
+  *cancel = (request_id != current_id);
+}
+
+std::string PrintPreviewUI::GetPrintPreviewUIAddress() const {
+  // Store the PrintPreviewUIAddress as a string.
+  // "0x" + deadc0de + '\0' = 2 + 2 * sizeof(this) + 1;
+  char preview_ui_addr[2 + (2 * sizeof(this)) + 1];
+  base::snprintf(preview_ui_addr, sizeof(preview_ui_addr), "%p", this);
+  return preview_ui_addr;
+}
+
 void PrintPreviewUI::OnInitiatorTabCrashed() {
   StringValue initiator_tab_url(initiator_url_);
   CallJavascriptFunction("onInitiatorTabCrashed", initiator_tab_url);
 }
 
 void PrintPreviewUI::OnInitiatorTabClosed() {
   StringValue initiator_tab_url(initiator_url_);
   CallJavascriptFunction("onInitiatorTabClosed", initiator_tab_url);
 }
 
-void PrintPreviewUI::OnPrintPreviewRequest() {
-  request_count_++;
+void PrintPreviewUI::OnPrintPreviewRequest(int request_id) {
+  g_print_preview_request_id_map.Get().Set(preview_ui_addr_str_, request_id);
 }
 
 void PrintPreviewUI::OnDidGetPreviewPageCount(
     const PrintHostMsg_DidGetPreviewPageCount_Params& params) {
   DCHECK_GT(params.page_count, 0);
-  document_cookie_ = params.document_cookie;
   base::FundamentalValue count(params.page_count);
   base::FundamentalValue modifiable(params.is_modifiable);
   base::FundamentalValue request_id(params.preview_request_id);
   StringValue title(initiator_tab_title_);
   CallJavascriptFunction("onDidGetPreviewPageCount", count, modifiable,
                          request_id, title);
 }
 
 void PrintPreviewUI::OnDidPreviewPage(int page_number,
                                       int preview_request_id) {
   DCHECK_GE(page_number, 0);
   base::FundamentalValue number(page_number);
   StringValue ui_identifier(preview_ui_addr_str_);
   base::FundamentalValue request_id(preview_request_id);
   CallJavascriptFunction("onDidPreviewPage", number, ui_identifier, request_id);
 }
 
 void PrintPreviewUI::OnReusePreviewData(int preview_request_id) {
-  DecrementRequestCount();
-
   base::StringValue ui_identifier(preview_ui_addr_str_);
   base::FundamentalValue ui_preview_request_id(preview_request_id);
   CallJavascriptFunction("reloadPreviewPages", ui_identifier,
                          ui_preview_request_id);
 }
 
 void PrintPreviewUI::OnPreviewDataIsAvailable(int expected_pages_count,
                                               int preview_request_id) {
   VLOG(1) << "Print preview request finished with "
           << expected_pages_count << " pages";
-  DecrementRequestCount();
 
   if (!initial_preview_start_time_.is_null()) {
     UMA_HISTOGRAM_TIMES("PrintPreview.InitalDisplayTime",
                         base::TimeTicks::Now() - initial_preview_start_time_);
     UMA_HISTOGRAM_COUNTS("PrintPreview.PageCount.Initial",
                          expected_pages_count);
     initial_preview_start_time_ = base::TimeTicks();
   }
   base::StringValue ui_identifier(preview_ui_addr_str_);
   base::FundamentalValue ui_preview_request_id(preview_request_id);
   CallJavascriptFunction("updatePrintPreview", ui_identifier,
                          ui_preview_request_id);
 }
 
 void PrintPreviewUI::OnTabDestroyed() {
   handler_->OnTabDestroyed();
 }
 
 void PrintPreviewUI::OnFileSelectionCancelled() {
   CallJavascriptFunction("fileSelectionCancelled");
 }
 
 void PrintPreviewUI::OnPrintPreviewFailed() {
-  DecrementRequestCount();
   CallJavascriptFunction("printPreviewFailed");
 }
 
-void PrintPreviewUI::OnPrintPreviewCancelled() {
-  DecrementRequestCount();
-}
-
-bool PrintPreviewUI::HasPendingRequests() {
-  return request_count_ > 1;
-}
-
 PrintPreviewDataService* PrintPreviewUI::print_preview_data_service() {
   return PrintPreviewDataService::GetInstance();
 }
-
-void PrintPreviewUI::DecrementRequestCount() {
-  if (request_count_ > 0)
-    request_count_--;
-}
-
-int PrintPreviewUI::document_cookie() {
-  return document_cookie_;
-}