extracted interface, eliminated possible exceptions due to small indent size diversity

platform/lang-api/src/com/intellij/psi/codeStyle/autodetect/IndentOptionsDetector.java

@@ -50,7 +50,7 @@ public class IndentOptionsDetector {
 
     if (myDocument != null) {
       List<LineIndentInfo> linesInfo = new LineIndentInfoBuilder(myDocument.getCharsSequence()).build();
-      IndentUsageStatistics stats = new IndentUsageStatistics(linesInfo);
+      IndentUsageStatistics stats = new IndentUsageStatisticsImpl(linesInfo);
       adjustIndentOptions(indentOptions, stats);
     }
 
@@ -80,18 +80,24 @@ public class IndentOptionsDetector {
   }
 
   private static int getPositiveIndentSize(@NotNull IndentUsageStatistics stats) {
-    IndentUsageInfo maxUsedIndentInfo = stats.getMaxUsedIndentInfo(0);
-    int maxIndentSize = maxUsedIndentInfo.getIndentSize();
-    if (maxIndentSize == 0) {
-      maxUsedIndentInfo = stats.getMaxUsedIndentInfo(1);
-      maxIndentSize = maxUsedIndentInfo.getIndentSize();
+    int totalIndentSizesDetected = stats.getTotalIndentSizesDetected();
+    if (totalIndentSizesDetected == 0) return -1;
+
+    IndentUsageInfo maxUsedIndentInfo = stats.getKMostUsedIndentInfo(0);
+    int maxUsedIndentSize = maxUsedIndentInfo.getIndentSize();
+
+    if (maxUsedIndentSize == 0) {
+      if (totalIndentSizesDetected < 1) return -1;
+
+      maxUsedIndentInfo = stats.getKMostUsedIndentInfo(1);
+      maxUsedIndentSize = maxUsedIndentInfo.getIndentSize();
     }
 
-    if (maxIndentSize <= MAX_INDENT_TO_DETECT) {
-      int totalUsagesWithoutZeroIndent = stats.getTotalLinesWithLeadingSpaces() - stats.getTimesUsedIndent(0);
+    if (maxUsedIndentSize <= MAX_INDENT_TO_DETECT) {
+      int totalUsagesWithoutZeroIndent = stats.getTotalLinesWithLeadingSpaces() - stats.getTimesIndentUsed(0);
       double usageRate = (double)maxUsedIndentInfo.getTimesUsed() / totalUsagesWithoutZeroIndent;
       if (usageRate > RATE_THRESHOLD) {
-        return maxIndentSize;
+        return maxUsedIndentSize;
       }
     }
 

platform/lang-api/src/com/intellij/psi/codeStyle/autodetect/IndentUsageStatistics.java

@@ -15,126 +15,16 @@
  */
 package com.intellij.psi.codeStyle.autodetect;
 
-import com.intellij.util.containers.ContainerUtil;
-import com.intellij.util.containers.Stack;
-import gnu.trove.TIntIntHashMap;
-import gnu.trove.TIntIntIterator;
-import org.jetbrains.annotations.NotNull;
+public interface IndentUsageStatistics {
 
-import java.util.Comparator;
-import java.util.List;
+  int getTotalLinesWithLeadingTabs();
 
-public class IndentUsageStatistics {
-  private static final Comparator<IndentUsageInfo> DECREASING_ORDER = new Comparator<IndentUsageInfo>() {
-    @Override
-    public int compare(@NotNull IndentUsageInfo o1, @NotNull IndentUsageInfo o2) {
-      return o1.getTimesUsed() < o2.getTimesUsed() ? 1 : o1.getTimesUsed() == o2.getTimesUsed() ? 0 : -1;
-    }
-  };
+  int getTotalLinesWithLeadingSpaces();
 
-  private List<LineIndentInfo> myLineInfos;
+  IndentUsageInfo getKMostUsedIndentInfo(int k);
 
-  private int myPreviousLineIndent;
-  private int myPreviousRelativeIndent;
+  int getTotalIndentSizesDetected();
 
-  private int myTotalLinesWithTabs = 0;
-  private int myTotalLinesWithWhiteSpaces = 0;
+  int getTimesIndentUsed(int indent);
 
-  private TIntIntHashMap myIndentToUsages = new TIntIntHashMap();
-  private List<IndentUsageInfo> myIndentUsages = ContainerUtil.newArrayList();
-  private Stack<IndentData> myParentIndents = ContainerUtil.newStack(new IndentData(0, 0));
-
-  public IndentUsageStatistics(@NotNull List<LineIndentInfo> lineInfos) {
-    myLineInfos = lineInfos;
-    buildIndentToUsagesMap();
-    myIndentUsages = toIndentUsageList(myIndentToUsages);
-    ContainerUtil.sort(myIndentUsages, DECREASING_ORDER);
-  }
-
-  @NotNull
-  private static List<IndentUsageInfo> toIndentUsageList(@NotNull TIntIntHashMap indentToUsages) {
-    List<IndentUsageInfo> indentUsageInfos = ContainerUtil.newArrayList();
-    TIntIntIterator it = indentToUsages.iterator();
-    while (it.hasNext()) {
-      it.advance();
-      indentUsageInfos.add(new IndentUsageInfo(it.key(), it.value()));
-    }
-    return indentUsageInfos;
-  }
-
-  public void buildIndentToUsagesMap() {
-    myPreviousLineIndent = 0;
-    myPreviousRelativeIndent = 0;
-
-    for (LineIndentInfo lineInfo : myLineInfos) {
-      if (lineInfo.isLineWithTabs()) {
-        myTotalLinesWithTabs++;
-      }
-      else if (lineInfo.isLineWithWhiteSpaceIndent()) {
-        handleWhiteSpaceIndent(lineInfo.getIndentSize());
-      }
-    }
-  }
-
-  @NotNull
-  private IndentData findParentIndent(int indent) {
-    while (myParentIndents.size() != 1 && myParentIndents.peek().indent > indent) {
-      myParentIndents.pop();
-    }
-    return myParentIndents.peek();
-  }
-
-  private void handleWhiteSpaceIndent(int currentIndent) {
-    int relativeIndent = currentIndent - myPreviousLineIndent;
-    if (relativeIndent < 0) {
-      IndentData indentData = findParentIndent(currentIndent);
-      myPreviousLineIndent = indentData.indent;
-      myPreviousRelativeIndent = indentData.relativeIndent;
-      relativeIndent = currentIndent - myPreviousLineIndent;
-    }
-
-    if (relativeIndent == 0) {
-      relativeIndent = myPreviousRelativeIndent;
-    }
-    else {
-      myParentIndents.push(new IndentData(currentIndent, relativeIndent));
-    }
-
-    increaseIndentUsage(relativeIndent);
-
-    myPreviousRelativeIndent = relativeIndent;
-    myPreviousLineIndent = currentIndent;
-    myTotalLinesWithWhiteSpaces++;
-  }
-
-  private void increaseIndentUsage(int relativeIndent) {
-    int timesUsed = myIndentToUsages.get(relativeIndent);
-    myIndentToUsages.put(relativeIndent, ++timesUsed);
-  }
-
-  public int getTotalLinesWithLeadingTabs() {
-    return myTotalLinesWithTabs;
-  }
-
-  public int getTotalLinesWithLeadingSpaces() {
-    return myTotalLinesWithWhiteSpaces;
-  }
-
-  public IndentUsageInfo getMaxUsedIndentInfo(int rank) {
-    return myIndentUsages.get(rank);
-  }
-
-  public int getTimesUsedIndent(int indent) {
-    return myIndentToUsages.get(indent);
-  }
-
-  private static class IndentData {
-    public final int indent;
-    public final int relativeIndent;
-
-    public IndentData(int indent, int relativeIndent) {
-      this.indent = indent;
-      this.relativeIndent = relativeIndent;
-    }
-  }
 }

platform/lang-api/src/com/intellij/psi/codeStyle/autodetect/IndentUsageStatisticsImpl.java

@@ -0,0 +1,149 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.psi.codeStyle.autodetect;
+
+import com.intellij.util.containers.ContainerUtil;
+import com.intellij.util.containers.Stack;
+import gnu.trove.TIntIntHashMap;
+import gnu.trove.TIntIntIterator;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Comparator;
+import java.util.List;
+
+public class IndentUsageStatisticsImpl implements IndentUsageStatistics {
+  private static final Comparator<IndentUsageInfo> DECREASING_ORDER = new Comparator<IndentUsageInfo>() {
+    @Override
+    public int compare(@NotNull IndentUsageInfo o1, @NotNull IndentUsageInfo o2) {
+      return o1.getTimesUsed() < o2.getTimesUsed() ? 1 : o1.getTimesUsed() == o2.getTimesUsed() ? 0 : -1;
+    }
+  };
+
+  private List<LineIndentInfo> myLineInfos;
+
+  private int myPreviousLineIndent;
+  private int myPreviousRelativeIndent;
+
+  private int myTotalLinesWithTabs = 0;
+  private int myTotalLinesWithWhiteSpaces = 0;
+
+  private TIntIntHashMap myIndentToUsages = new TIntIntHashMap();
+  private List<IndentUsageInfo> myIndentUsages = ContainerUtil.newArrayList();
+  private Stack<IndentData> myParentIndents = ContainerUtil.newStack(new IndentData(0, 0));
+
+  public IndentUsageStatisticsImpl(@NotNull List<LineIndentInfo> lineInfos) {
+    myLineInfos = lineInfos;
+    buildIndentToUsagesMap();
+    myIndentUsages = toIndentUsageList(myIndentToUsages);
+    ContainerUtil.sort(myIndentUsages, DECREASING_ORDER);
+  }
+
+  @NotNull
+  private static List<IndentUsageInfo> toIndentUsageList(@NotNull TIntIntHashMap indentToUsages) {
+    List<IndentUsageInfo> indentUsageInfos = ContainerUtil.newArrayList();
+    TIntIntIterator it = indentToUsages.iterator();
+    while (it.hasNext()) {
+      it.advance();
+      indentUsageInfos.add(new IndentUsageInfo(it.key(), it.value()));
+    }
+    return indentUsageInfos;
+  }
+
+  public void buildIndentToUsagesMap() {
+    myPreviousLineIndent = 0;
+    myPreviousRelativeIndent = 0;
+
+    for (LineIndentInfo lineInfo : myLineInfos) {
+      if (lineInfo.isLineWithTabs()) {
+        myTotalLinesWithTabs++;
+      }
+      else if (lineInfo.isLineWithWhiteSpaceIndent()) {
+        handleWhiteSpaceIndent(lineInfo.getIndentSize());
+      }
+    }
+  }
+
+  @NotNull
+  private IndentData findParentIndent(int indent) {
+    while (myParentIndents.size() != 1 && myParentIndents.peek().indent > indent) {
+      myParentIndents.pop();
+    }
+    return myParentIndents.peek();
+  }
+
+  private void handleWhiteSpaceIndent(int currentIndent) {
+    int relativeIndent = currentIndent - myPreviousLineIndent;
+    if (relativeIndent < 0) {
+      IndentData indentData = findParentIndent(currentIndent);
+      myPreviousLineIndent = indentData.indent;
+      myPreviousRelativeIndent = indentData.relativeIndent;
+      relativeIndent = currentIndent - myPreviousLineIndent;
+    }
+
+    if (relativeIndent == 0) {
+      relativeIndent = myPreviousRelativeIndent;
+    }
+    else {
+      myParentIndents.push(new IndentData(currentIndent, relativeIndent));
+    }
+
+    increaseIndentUsage(relativeIndent);
+
+    myPreviousRelativeIndent = relativeIndent;
+    myPreviousLineIndent = currentIndent;
+    myTotalLinesWithWhiteSpaces++;
+  }
+
+  private void increaseIndentUsage(int relativeIndent) {
+    int timesUsed = myIndentToUsages.get(relativeIndent);
+    myIndentToUsages.put(relativeIndent, ++timesUsed);
+  }
+
+  @Override
+  public int getTotalLinesWithLeadingTabs() {
+    return myTotalLinesWithTabs;
+  }
+
+  @Override
+  public int getTotalLinesWithLeadingSpaces() {
+    return myTotalLinesWithWhiteSpaces;
+  }
+
+  @Override
+  public IndentUsageInfo getKMostUsedIndentInfo(int k) {
+    return myIndentUsages.get(k);
+  }
+
+  @Override
+  public int getTimesIndentUsed(int indent) {
+    return myIndentToUsages.get(indent);
+  }
+
+  @Override
+  public int getTotalIndentSizesDetected() {
+    return myIndentToUsages.size();
+  }
+
+  private static class IndentData {
+    public final int indent;
+    public final int relativeIndent;
+
+    public IndentData(int indent, int relativeIndent) {
+      this.indent = indent;
+      this.relativeIndent = relativeIndent;
+    }
+  }
+}

platform/platform-tests/testSrc/com/intellij/psi/autodetect/IndentAutoDetectionTest.java

@@ -112,8 +112,8 @@ public class IndentAutoDetectionTest extends LightPlatformCodeInsightTestCase {
     configureByFile(getTestName(true) + ".java");
     Document document = getDocument(myFile);
     List<LineIndentInfo> lines = new LineIndentInfoBuilder(document.getCharsSequence()).build();
-    IndentUsageStatistics statistics = new IndentUsageStatistics(lines);
-    return statistics.getMaxUsedIndentInfo(0);
+    IndentUsageStatistics statistics = new IndentUsageStatisticsImpl(lines);
+    return statistics.getKMostUsedIndentInfo(0);
   }
 
   private static void doTestLineToIndentMapping(@NotNull CharSequence text, int... spacesForLine) {