PY-9795 Move various indent operation on string to PyIndentUtil

python/src/com/jetbrains/python/documentation/SectionBasedDocString.java

@@ -19,7 +19,6 @@ import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Pair;
-import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.util.Function;
 import com.intellij.util.containers.ContainerUtil;
 import com.jetbrains.python.psi.PyIndentUtil;
@@ -259,33 +258,6 @@ public abstract class SectionBasedDocString extends DocStringLineParser implemen
     return line.split(":", 1);
   }
 
-  // like Python's textwrap.dedent()
-  @NotNull
-  protected static String stripCommonIndent(@NotNull Substring text, boolean ignoreFirstStringIfNonEmpty) {
-    final List<Substring> lines = text.splitLines();
-    if (lines.isEmpty()) {
-      return "";
-    }
-    final String firstLine = lines.get(0).toString();
-    final boolean skipFirstLine = ignoreFirstStringIfNonEmpty && !StringUtil.isEmptyOrSpaces(firstLine);
-    final Iterable<Substring> workList = lines.subList(skipFirstLine ? 1 : 0, lines.size());
-    int curMinIndent = Integer.MAX_VALUE;
-    for (Substring line : workList) {
-      if (StringUtil.isEmptyOrSpaces(line)) {
-        continue;
-      }
-      curMinIndent = Math.min(curMinIndent, PyIndentUtil.getLineIndentSize(line));
-    }
-    final int minIndent = curMinIndent;
-    final List<String> dedentedLines = ContainerUtil.map(workList, new Function<Substring, String>() {
-      @Override
-      public String fun(Substring line) {
-        return line.substring(Math.min(line.length(), minIndent)).toString();
-      }
-    });
-    return StringUtil.join(skipFirstLine ? ContainerUtil.prepend(dedentedLines, firstLine) : dedentedLines, "\n");
-  }
-
   @NotNull
   public List<Section> getSections() {
     return Collections.unmodifiableList(mySections);
@@ -624,7 +596,7 @@ public abstract class SectionBasedDocString extends DocStringLineParser implemen
 
     @NotNull 
     public String getDescription() {
-      return myDescription == null ? "" : stripCommonIndent(myDescription, true);
+      return myDescription == null ? "" : PyIndentUtil.removeCommonIndent(myDescription.getValue(), true);
     }
 
     @Nullable

python/src/com/jetbrains/python/psi/PyIndentUtil.java

@@ -15,7 +15,9 @@
  */
 package com.jetbrains.python.psi;
 
+import com.google.common.collect.Iterables;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.text.LineTokenizer;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
@@ -23,9 +25,14 @@ import com.intellij.psi.PsiWhiteSpace;
 import com.intellij.psi.codeStyle.CodeStyleSettings;
 import com.intellij.psi.codeStyle.CodeStyleSettingsManager;
 import com.intellij.psi.util.PsiTreeUtil;
+import com.intellij.util.Function;
+import com.intellij.util.containers.ContainerUtil;
 import com.jetbrains.python.PythonFileType;
 import org.jetbrains.annotations.NotNull;
 
+import java.util.Collections;
+import java.util.List;
+
 /**
  * @author Mikhail Golubev
  */
@@ -99,4 +106,89 @@ public class PyIndentUtil {
   public static String getIndentFromSettings(@NotNull Project project) {
     return StringUtil.repeatSymbol(' ', getIndentSizeFromSettings(project));
   }
+
+  @NotNull
+  public static List<String> removeCommonIndent(@NotNull Iterable<String> lines, boolean ignoreFirstLine) {
+    return changeIndent(lines, ignoreFirstLine, "");
+  }
+
+  @NotNull
+  public static String removeCommonIndent(@NotNull String s, boolean ignoreFirstLine) {
+    final List<String> trimmed = removeCommonIndent(LineTokenizer.tokenizeIntoList(s, false), ignoreFirstLine);
+    return StringUtil.join(trimmed, "\n");
+  }
+
+  @NotNull
+  public static String changeIndent(@NotNull String s, boolean ignoreFirstLine, String newIndent) {
+    final List<String> trimmed = changeIndent(LineTokenizer.tokenizeIntoList(s, false), ignoreFirstLine, newIndent);
+    return StringUtil.join(trimmed, "\n");
+  }
+
+
+
+  /**
+   * Not that all empty lines will be trimmed.
+   */
+  @NotNull
+  public static List<String> changeIndent(@NotNull Iterable<String> lines, boolean ignoreFirstLine, final String newIndent) {
+    final String oldIndent = findCommonIndent(lines, ignoreFirstLine);
+    if (Iterables.isEmpty(lines)) {
+      return Collections.emptyList();
+    }
+
+    final List<String> result = ContainerUtil.map(Iterables.skip(lines, ignoreFirstLine ? 1 : 0), new Function<String, String>() {
+      @Override
+      public String fun(String line) {
+        if (StringUtil.isEmptyOrSpaces(line)) {
+          return "";
+        }
+        else {
+          return newIndent + line.substring(oldIndent.length());
+        }
+      }
+    });
+    if (ignoreFirstLine) {
+      return ContainerUtil.prepend(result, Iterables.get(lines, 0));
+    }
+    return result;
+  }
+
+  /**
+   * If lines include non-empty lines, all empty lines or lines that contain only spaces are ignored.
+   * Otherwise (all line are empty) their common indent are returned as expected. If any two lines
+   * have different indentation (e.g. one contains tab character and another doesn't), empty prefix
+   * is returned.
+   */
+  @NotNull
+  public static String findCommonIndent(@NotNull Iterable<String> lines, boolean ignoreFirstLine) {
+    String minIndent = null;
+    boolean allLinesEmpty = true;
+    if (Iterables.isEmpty(lines)) {
+      return "";
+    }
+    boolean hasBadEmptyLineIndent = false;
+    for (String line : Iterables.skip(lines, ignoreFirstLine ? 1 : 0)) {
+      final boolean lineEmpty = StringUtil.isEmptyOrSpaces(line);
+      if (lineEmpty && !allLinesEmpty) {
+        continue;
+      }
+      final String indent = (String)getLineIndent(line);
+      if (minIndent == null || (!lineEmpty && allLinesEmpty) || minIndent.startsWith(indent)) {
+        minIndent = indent;
+      }
+      else if (!indent.startsWith(minIndent)) {
+        if (lineEmpty) {
+          hasBadEmptyLineIndent = true;
+        }
+        else {
+          return "";
+        }
+      }
+      allLinesEmpty &= lineEmpty;
+    }
+    if (allLinesEmpty && hasBadEmptyLineIndent) {
+      return "";
+    }
+    return StringUtil.notNullize(minIndent);
+  }
 }