Stop fetching the next page if the first page has no content

components/dom_distiller/core/distiller.cc

 // Copyright 2013 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 "components/dom_distiller/core/distiller.h"
 
 #include <map>
 #include <utility>
 #include <vector>
 
@@ skipping 123 matching lines @@
                    url));
   }
 }
 
 void DistillerImpl::OnPageDistillationFinished(
     int page_num,
     const GURL& page_url,
     scoped_ptr<proto::DomDistillerResult> distiller_result,
     bool distillation_successful) {
   DCHECK(started_pages_index_.find(page_num) != started_pages_index_.end());
-  if (distillation_successful) {
+  if (!distillation_successful) {
+    started_pages_index_.erase(page_num);
+    RunDistillerCallbackIfDone();
+    return;
+  }
 
-    if (distiller_result->has_statistics_info() && page_num == 0) {
-      if (distiller_result->statistics_info().has_word_count()) {
-        UMA_HISTOGRAM_CUSTOM_COUNTS(
-            "DomDistiller.Statistics.FirstPageWordCount",
-            distiller_result->statistics_info().word_count(),
-            1, 4000, 50);
+  if (distiller_result->has_statistics_info() && page_num == 0) {
+    if (distiller_result->statistics_info().has_word_count()) {
+      UMA_HISTOGRAM_CUSTOM_COUNTS(
+          "DomDistiller.Statistics.FirstPageWordCount",
+          distiller_result->statistics_info().word_count(),
+          1, 4000, 50);
+    }
+  }
+
+  DCHECK(distiller_result.get());
+  DistilledPageData* page_data =
+      GetPageAtIndex(started_pages_index_[page_num]);
+  page_data->distilled_page_proto =
+      new base::RefCountedData<DistilledPageProto>();
+  page_data->page_num = page_num;
+  if (distiller_result->has_title()) {
+    page_data->distilled_page_proto->data.set_title(
+        distiller_result->title());
+  }
+  page_data->distilled_page_proto->data.set_url(page_url.spec());
+  bool content_empty = true;
+  if (distiller_result->has_distilled_content() &&
+      distiller_result->distilled_content().has_html()) {
+    page_data->distilled_page_proto->data.set_html(
+        distiller_result->distilled_content().html());
+    if (!distiller_result->distilled_content().html().empty()) {
+      content_empty = false;
+    }
+  }
+
+  if (distiller_result->has_timing_info()) {
+    const proto::TimingInfo& distiller_timing_info =
+        distiller_result->timing_info();
+    DistilledPageProto::TimingInfo timing_info;
+    if (distiller_timing_info.has_markup_parsing_time()) {
+      timing_info.set_name("markup_parsing");
+      timing_info.set_time(distiller_timing_info.markup_parsing_time());
+      *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    }
+
+    if (distiller_timing_info.has_document_construction_time()) {
+      timing_info.set_name("document_construction");
+      timing_info.set_time(
+          distiller_timing_info.document_construction_time());
+      *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    }
+
+    if (distiller_timing_info.has_article_processing_time()) {
+      timing_info.set_name("article_processing");
+      timing_info.set_time(
+          distiller_timing_info.article_processing_time());
+      *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    }
+
+    if (distiller_timing_info.has_formatting_time()) {
+      timing_info.set_name("formatting");
+      timing_info.set_time(
+          distiller_timing_info.formatting_time());
+      *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    }
+
+    if (distiller_timing_info.has_total_time()) {
+      timing_info.set_name("total");
+      timing_info.set_time(
+          distiller_timing_info.total_time());
+      *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    }
+
+    for (int i = 0; i < distiller_timing_info.other_times_size(); i++) {
+      timing_info.set_name(distiller_timing_info.other_times(i).name());
+      timing_info.set_time(distiller_timing_info.other_times(i).time());
+      *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    }
+  }
+
+  if (distiller_result->has_debug_info() &&
+      distiller_result->debug_info().has_log()) {
+    page_data->distilled_page_proto->data.mutable_debug_info()->set_log(
+        distiller_result->debug_info().log());
+  }
+
+  if (distiller_result->has_text_direction()) {
+    page_data->distilled_page_proto->data.set_text_direction(
+        distiller_result->text_direction());
+  } else {
+    page_data->distilled_page_proto->data.set_text_direction("auto");
+  }
+
+  if (distiller_result->has_pagination_info()) {
+    const proto::PaginationInfo& pagination_info =
+        distiller_result->pagination_info();
+    // Skip the next page if the first page is empty.
+    if (pagination_info.has_next_page() &&
+        (page_num != 0 || !content_empty)) {
+      GURL next_page_url(pagination_info.next_page());
+      if (next_page_url.is_valid()) {
+        // The pages should be in same origin.
+        DCHECK_EQ(next_page_url.GetOrigin(), page_url.GetOrigin());
+        AddToDistillationQueue(page_num + 1, next_page_url);
+        page_data->distilled_page_proto->data.mutable_pagination_info()->
+            set_next_page(next_page_url.spec());
       }
     }
 
-    DCHECK(distiller_result.get());
-    DistilledPageData* page_data =
-        GetPageAtIndex(started_pages_index_[page_num]);
-    page_data->distilled_page_proto =
-        new base::RefCountedData<DistilledPageProto>();
-    page_data->page_num = page_num;
-    if (distiller_result->has_title()) {
-      page_data->distilled_page_proto->data.set_title(
-          distiller_result->title());
-    }
-    page_data->distilled_page_proto->data.set_url(page_url.spec());
-    if (distiller_result->has_distilled_content() &&
-        distiller_result->distilled_content().has_html()) {
-      page_data->distilled_page_proto->data.set_html(
-          distiller_result->distilled_content().html());
-    }
-
-    if (distiller_result->has_timing_info()) {
-      const proto::TimingInfo& distiller_timing_info =
-          distiller_result->timing_info();
-      DistilledPageProto::TimingInfo timing_info;
-      if (distiller_timing_info.has_markup_parsing_time()) {
-        timing_info.set_name("markup_parsing");
-        timing_info.set_time(distiller_timing_info.markup_parsing_time());
-        *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
-      }
-
-      if (distiller_timing_info.has_document_construction_time()) {
-        timing_info.set_name("document_construction");
-        timing_info.set_time(
-            distiller_timing_info.document_construction_time());
-        *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
-      }
-
-      if (distiller_timing_info.has_article_processing_time()) {
-        timing_info.set_name("article_processing");
-        timing_info.set_time(
-            distiller_timing_info.article_processing_time());
-        *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
-      }
-
-      if (distiller_timing_info.has_formatting_time()) {
-        timing_info.set_name("formatting");
-        timing_info.set_time(
-            distiller_timing_info.formatting_time());
-        *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
-      }
-
-      if (distiller_timing_info.has_total_time()) {
-        timing_info.set_name("total");
-        timing_info.set_time(
-            distiller_timing_info.total_time());
-        *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
-      }
-
-      for (int i = 0; i < distiller_timing_info.other_times_size(); i++) {
-        timing_info.set_name(distiller_timing_info.other_times(i).name());
-        timing_info.set_time(distiller_timing_info.other_times(i).time());
-        *page_data->distilled_page_proto->data.add_timing_info() = timing_info;
+    if (pagination_info.has_prev_page()) {
+      GURL prev_page_url(pagination_info.prev_page());
+      if (prev_page_url.is_valid()) {
+        DCHECK_EQ(prev_page_url.GetOrigin(), page_url.GetOrigin());
+        AddToDistillationQueue(page_num - 1, prev_page_url);
+        page_data->distilled_page_proto->data.mutable_pagination_info()->
+            set_prev_page(prev_page_url.spec());
       }
     }
 
-    if (distiller_result->has_debug_info() &&
-        distiller_result->debug_info().has_log()) {
-      page_data->distilled_page_proto->data.mutable_debug_info()->set_log(
-          distiller_result->debug_info().log());
-    }
-
-    if (distiller_result->has_text_direction()) {
-      page_data->distilled_page_proto->data.set_text_direction(
-          distiller_result->text_direction());
-    } else {
-      page_data->distilled_page_proto->data.set_text_direction("auto");
-    }
-
-    if (distiller_result->has_pagination_info()) {
-      const proto::PaginationInfo& pagination_info =
-          distiller_result->pagination_info();
-      if (pagination_info.has_next_page()) {
-        GURL next_page_url(pagination_info.next_page());
-        if (next_page_url.is_valid()) {
-          // The pages should be in same origin.
-          DCHECK_EQ(next_page_url.GetOrigin(), page_url.GetOrigin());
-          AddToDistillationQueue(page_num + 1, next_page_url);
-          page_data->distilled_page_proto->data.mutable_pagination_info()->
-              set_next_page(next_page_url.spec());
-        }
-      }
-
-      if (pagination_info.has_prev_page()) {
-        GURL prev_page_url(pagination_info.prev_page());
-        if (prev_page_url.is_valid()) {
-          DCHECK_EQ(prev_page_url.GetOrigin(), page_url.GetOrigin());
-          AddToDistillationQueue(page_num - 1, prev_page_url);
-          page_data->distilled_page_proto->data.mutable_pagination_info()->
-              set_prev_page(prev_page_url.spec());
-        }
-      }
-
-      if (pagination_info.has_canonical_page()) {
-        GURL canonical_page_url(pagination_info.canonical_page());
-        if (canonical_page_url.is_valid()) {
-          page_data->distilled_page_proto->data.mutable_pagination_info()->
-              set_canonical_page(canonical_page_url.spec());
-        }
+    if (pagination_info.has_canonical_page()) {
+      GURL canonical_page_url(pagination_info.canonical_page());
+      if (canonical_page_url.is_valid()) {
+        page_data->distilled_page_proto->data.mutable_pagination_info()->
+            set_canonical_page(canonical_page_url.spec());
       }
     }
+  }
 
-    for (int img_num = 0; img_num < distiller_result->content_images_size();
-         ++img_num) {
-      std::string image_id =
-          base::IntToString(page_num + 1) + "_" + base::IntToString(img_num);
-      FetchImage(page_num, image_id,
-          distiller_result->content_images(img_num).url());
-    }
+  for (int img_num = 0; img_num < distiller_result->content_images_size();
+       ++img_num) {
+    std::string image_id =
+        base::IntToString(page_num + 1) + "_" + base::IntToString(img_num);
+    FetchImage(page_num, image_id,
+        distiller_result->content_images(img_num).url());
+  }
 
-    AddPageIfDone(page_num);
-    DistillNextPage();
-  } else {
-    started_pages_index_.erase(page_num);
-    RunDistillerCallbackIfDone();
-  }
+  AddPageIfDone(page_num);
+  DistillNextPage();
 }
 
 void DistillerImpl::FetchImage(int page_num,
                                const std::string& image_id,
                                const std::string& image_url) {
   if (!GURL(image_url).is_valid()) return;
   DCHECK(started_pages_index_.find(page_num) != started_pages_index_.end());
   DistilledPageData* page_data = GetPageAtIndex(started_pages_index_[page_num]);
   DistillerURLFetcher* fetcher =
       distiller_url_fetcher_factory_.CreateDistillerURLFetcher();
@@ skipping 101 matching lines @@
     DCHECK(finished_pages_index_.empty());
 
     base::AutoReset<bool> dont_delete_this_in_callback(&destruction_allowed_,
                                                        false);
     finished_cb_.Run(std::move(article_proto));
     finished_cb_.Reset();
   }
 }
 
 }  // namespace dom_distiller