From e60023eb8b9203492312707c4dbeb9d4cb4ee72e Mon Sep 17 00:00:00 2001
From: Toparvion <toparvion@gmx.com>
Date: Wed, 7 Dec 2016 23:57:57 +0700
Subject: [PATCH] Added "read back" feature - re-fetching last log lines if no
 new lines loaded

---
 .../testing/analog/model/ReadingMetaData.java | 16 +++++--
 .../testing/analog/service/AnaLogUtils.java   |  8 ++--
 .../analog/service/MainController.java        | 44 ++++++++++++-------
 src/main/resources/static/index.html          |  2 +-
 .../resources/static/js/main-controller.js    | 14 +++---
 .../resources/static/js/provider-service.js   |  5 ++-
 6 files changed, 57 insertions(+), 32 deletions(-)

diff --git a/src/main/java/ru/ftc/upc/testing/analog/model/ReadingMetaData.java b/src/main/java/ru/ftc/upc/testing/analog/model/ReadingMetaData.java
index fd5fe42..a9d6b11 100644
--- a/src/main/java/ru/ftc/upc/testing/analog/model/ReadingMetaData.java
+++ b/src/main/java/ru/ftc/upc/testing/analog/model/ReadingMetaData.java
@@ -8,9 +8,13 @@
  * Time: 12:48
  */
 public class ReadingMetaData implements Serializable {
-  private long prependingCounter = -1L;
-  private long appendingCounter = 0L;
-  private long fileSavedSize = 0L;
+  private long prependingCounter;
+  private long appendingCounter;
+  private long fileSavedSize;
+
+  public ReadingMetaData() {
+    reset();
+  }
 
   public long getPrependingCounter() {
     return prependingCounter;
@@ -39,4 +43,10 @@ public void setFileSavedSize(long fileSavedSize) {
   public boolean isPrependingCounterSet() {
     return (prependingCounter != -1L);
   }
+
+  public void reset() {
+    prependingCounter = -1L;
+    appendingCounter = 0L;
+    fileSavedSize = 0L;
+  }
 }
diff --git a/src/main/java/ru/ftc/upc/testing/analog/service/AnaLogUtils.java b/src/main/java/ru/ftc/upc/testing/analog/service/AnaLogUtils.java
index 9a9ee80..18a9859 100644
--- a/src/main/java/ru/ftc/upc/testing/analog/service/AnaLogUtils.java
+++ b/src/main/java/ru/ftc/upc/testing/analog/service/AnaLogUtils.java
@@ -169,10 +169,10 @@ public static String detectMessageType(String curLine) {
     return "UNKNOWN";
   }
 
-  public static List<String> getRawLines(String inputFileName,
-                                         String encoding,
-                                         ReadingMetaData readingMetaData,
-                                         Long prependingSnippetSizePercent) throws Exception {
+  static List<String> getRawLines(String inputFileName,
+                                  String encoding,
+                                  ReadingMetaData readingMetaData,
+                                  Long prependingSnippetSizePercent) throws Exception {
     // проверяем наличие указанного файла
     File inputFile = new File(inputFileName);
     if (!inputFile.exists() || !inputFile.isFile()) {
diff --git a/src/main/java/ru/ftc/upc/testing/analog/service/MainController.java b/src/main/java/ru/ftc/upc/testing/analog/service/MainController.java
index a2252c6..b785edd 100644
--- a/src/main/java/ru/ftc/upc/testing/analog/service/MainController.java
+++ b/src/main/java/ru/ftc/upc/testing/analog/service/MainController.java
@@ -43,27 +43,19 @@ public MainController(ChoicesProperties choicesProperties, EncodingDetector enco
 
   @RequestMapping("/provide")
   public Part provide(@RequestParam("log") String inputFileName,
-                      @RequestParam(name = "prependingSize", required = false) Long prependingSize,
+                      @RequestParam(required = false, name = "prependingSize") Long prependingSize,
                       @RequestParam(required = false, defaultValue = "UTF-8") String encoding,
+                      @RequestParam(required = false, defaultValue = "false") boolean readBackAllowed,
                       HttpSession session) {
     // получаем данные о предыдущем чтении
     ReadingMetaData readingMetaData = AnaLogUtils.retrieveMetaData(session, inputFileName);
 
     // получаем сырой набор строк из файла
-    List<String> rawLines;
-    try {
-      rawLines = AnaLogUtils.getRawLines(inputFileName, encoding, readingMetaData, prependingSize);
-
-    } catch (FileNotFoundException e) {
-      log.warn("Ошибка при чтении заданного файла: " + e.getMessage());
-      throw new RuntimeException(e);
-
-    } catch (Exception e) {
-      log.error("Internal application error: ", e);
-      throw new RuntimeException(e);
-    }
-    if (!rawLines.isEmpty()) {
-      log.trace("Raw lines read: {}", rawLines.size());
+    List<String> rawLines = fetchRawLines(inputFileName, prependingSize, encoding, readingMetaData);
+    if (rawLines.isEmpty() && readBackAllowed) {
+      log.debug("No new lines fetched. Attempting to read back...");
+      readingMetaData.reset();
+      rawLines = fetchRawLines(inputFileName, prependingSize, encoding, readingMetaData);
     }
 
     List<Line> parsedLines = new ArrayList<>();
@@ -83,6 +75,28 @@ public Part provide(@RequestParam("log") String inputFileName,
     return new Part(parsedLines);
   }
 
+  private List<String> fetchRawLines(String inputFileName,
+                                     Long prependingSize,
+                                     String encoding,
+                                     ReadingMetaData readingMetaData) {
+    List<String> rawLines;
+    try {
+      rawLines = AnaLogUtils.getRawLines(inputFileName, encoding, readingMetaData, prependingSize);
+
+    } catch (FileNotFoundException e) {
+      log.warn("Ошибка при чтении заданного файла: " + e.getMessage());
+      throw new RuntimeException(e);
+
+    } catch (Exception e) {
+      log.error("Internal application error: ", e);
+      throw new RuntimeException(e);
+    }
+    if (!rawLines.isEmpty()) {
+      log.trace("Raw lines read: {}", rawLines.size());
+    }
+    return rawLines;
+  }
+
   @RequestMapping("/choices")
   public List<LogChoice> choices() {
     return choices.stream()
diff --git a/src/main/resources/static/index.html b/src/main/resources/static/index.html
index 681a120..3e801dd 100644
--- a/src/main/resources/static/index.html
+++ b/src/main/resources/static/index.html
@@ -23,7 +23,7 @@
     <label>
         <input type="checkbox" name="updateToggler" ng-model="onAir"/>Обновлять ежесекундно&nbsp;
     </label>
-    <button name="updateNowButton" ng-click="updateLog()" ng-disabled="onAir">Обновить сейчас</button>
+    <button name="updateNowButton" ng-click="updateLog(false)" ng-disabled="onAir">Обновить сейчас</button>
     &nbsp;
 <!--
     <label>
diff --git a/src/main/resources/static/js/main-controller.js b/src/main/resources/static/js/main-controller.js
index b8922d9..f9babb0 100644
--- a/src/main/resources/static/js/main-controller.js
+++ b/src/main/resources/static/js/main-controller.js
@@ -19,10 +19,10 @@ app.controller('controlPanelController', function ($scope, $rootScope,
         $location.path($scope.selectedLog.path);
         $scope.onAir = false;
         renderingService.clearQueue();
-        $scope.updateLog($scope.selectedLog);
+        $scope.updateLog(/*readBackAllowed:*/true);
     };
-    $scope.updateLog = function () {
-        providerService($scope.selectedLog.path, $scope.encoding, $scope.stopOnAir)
+    $scope.updateLog = function (isReadBackAllowed) {
+        providerService($scope.selectedLog.path, $scope.encoding, $scope.stopOnAir, isReadBackAllowed)
     };
     $scope.disableOnAirPoller = function() {
         if (angular.isDefined(onAirPromise)) {
@@ -36,7 +36,7 @@ app.controller('controlPanelController', function ($scope, $rootScope,
     });
     $scope.prepend = function () {
         $scope.onAir = false;
-        providerService($scope.selectedLog.path, $scope.encoding, $scope.stopOnAir, $scope.prependingSize);
+        providerService($scope.selectedLog.path, $scope.encoding, $scope.stopOnAir, false, $scope.prependingSize);
     };
     $scope.clear = function () {
         renderingService.clearQueue();
@@ -53,7 +53,7 @@ app.controller('controlPanelController', function ($scope, $rootScope,
             $scope.selectedLog = selectedChoice;
             $scope.encoding = selectedChoice.encoding;
             $rootScope.watchingLog = selectedChoice.title + " - АнаЛог";
-            $scope.updateLog();
+            $scope.updateLog(/*readBackAllowed:*/true);
         });
     }
     // the following watch allows us to react to URL path change instantly (without opening a new browser tab)
@@ -76,8 +76,8 @@ app.controller('controlPanelController', function ($scope, $rootScope,
     }, function () {
         $log.log("Turning onAir to: " + $scope.onAir);
         if ($scope.onAir) {
-            onAirPromise = $interval($scope.updateLog, 1000);
-            $scope.updateLog();    // in order not to wait for the first interval triggering
+            onAirPromise = $interval(function() {$scope.updateLog(false)}, 1000);
+            $scope.updateLog(false);    // in order not to wait for the first interval triggering
         } else {
             $scope.disableOnAirPoller();
         }
diff --git a/src/main/resources/static/js/provider-service.js b/src/main/resources/static/js/provider-service.js
index e18d93b..976c224 100644
--- a/src/main/resources/static/js/provider-service.js
+++ b/src/main/resources/static/js/provider-service.js
@@ -1,8 +1,9 @@
 function ProviderService($http, $window, renderingService) {
-    return function (logPath, encoding, errorCallback, prependingSize) {
+    return function (logPath, encoding, errorCallback, isReadBackAllowed, prependingSize) {
         var params = {
             log: logPath,
-            encoding: encoding
+            encoding: encoding,
+            readBackAllowed: isReadBackAllowed
         };
         if (prependingSize) {
             params.prependingSize = prependingSize;