1 files changed, 106 insertions, 0 deletions
diff --git a/platform/lang-api/src/com/intellij/psi/codeStyle/autodetect/IndentOptionsDetector.java b/platform/lang-api/src/com/intellij/psi/codeStyle/autodetect/IndentOptionsDetector.java
new file mode 100644
index 000000000000..527ee9e79a49
--- /dev/null
+++ b/platform/lang-api/src/com/intellij/psi/codeStyle/autodetect/IndentOptionsDetector.java
@@ -0,0 +1,106 @@
+/*
+ * 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.openapi.diagnostic.Logger;
+import com.intellij.openapi.editor.Document;
+import com.intellij.openapi.project.Project;
+import com.intellij.psi.PsiDocumentManager;
+import com.intellij.psi.PsiFile;
+import com.intellij.psi.codeStyle.CodeStyleSettingsManager;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+import static com.intellij.psi.codeStyle.CommonCodeStyleSettings.*;
+
+public class IndentOptionsDetector {
+  private static Logger LOG = Logger.getInstance("#com.intellij.psi.codeStyle.CommonCodeStyleSettings.IndentOptionsDetector");
+
+  private static final double RATE_THRESHOLD = 0.8;
+  private static final int MIN_LINES_THRESHOLD = 50;
+  private static final int MAX_INDENT_TO_DETECT = 8;
+
+  private final PsiFile myFile;
+  private final Project myProject;
+  private final Document myDocument;
+
+  public IndentOptionsDetector(@NotNull PsiFile file) {
+    myFile = file;
+    myProject = file.getProject();
+    myDocument = PsiDocumentManager.getInstance(myProject).getDocument(myFile);
+  }
+
+  @NotNull
+  public IndentOptions getIndentOptions() {
+    IndentOptions indentOptions = (IndentOptions)CodeStyleSettingsManager.getSettings(myProject).getIndentOptions(myFile.getFileType()).clone();
+
+    if (myDocument != null) {
+      List<LineIndentInfo> linesInfo = new LineIndentInfoBuilder(myDocument.getCharsSequence()).build();
+      IndentUsageStatistics stats = new IndentUsageStatisticsImpl(linesInfo);
+      adjustIndentOptions(indentOptions, stats);
+    }
+
+    return indentOptions;
+  }
+
+  private void adjustIndentOptions(@NotNull IndentOptions indentOptions, @NotNull IndentUsageStatistics stats) {
+    int linesWithTabs = stats.getTotalLinesWithLeadingTabs();
+    int linesWithWhiteSpaceIndent = stats.getTotalLinesWithLeadingSpaces();
+
+    int totalLines = linesWithTabs + linesWithWhiteSpaceIndent;
+    double lineWithTabsRate = (double)linesWithTabs / totalLines;
+
+    if (linesWithTabs > MIN_LINES_THRESHOLD && lineWithTabsRate > RATE_THRESHOLD) {
+      if (!indentOptions.USE_TAB_CHARACTER) {
+        indentOptions.USE_TAB_CHARACTER = true;
+        LOG.info("Detected tab usage in" + myFile);
+      }
+    }
+    else if (linesWithWhiteSpaceIndent > MIN_LINES_THRESHOLD && (1 - lineWithTabsRate) > RATE_THRESHOLD) {
+      int newIndentSize = getPositiveIndentSize(stats);
+      if (newIndentSize > 0 && indentOptions.INDENT_SIZE != newIndentSize) {
+        indentOptions.INDENT_SIZE = newIndentSize;
+        LOG.info("Detected indent size: " + newIndentSize + " for file " + myFile);
+      }
+    }
+  }
+
+  private static int getPositiveIndentSize(@NotNull IndentUsageStatistics stats) {
+    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 (maxUsedIndentSize <= MAX_INDENT_TO_DETECT) {
+      int totalUsagesWithoutZeroIndent = stats.getTotalLinesWithLeadingSpaces() - stats.getTimesIndentUsed(0);
+      double usageRate = (double)maxUsedIndentInfo.getTimesUsed() / totalUsagesWithoutZeroIndent;
+      if (usageRate > RATE_THRESHOLD) {
+        return maxUsedIndentSize;
+      }
+    }
+
+    return -1;
+  }
+}