Move SetComposingLength to TextRange::set_length

Author: cbracken

shell/platform/common/cpp/text_input_model.cc

@@ -78,7 +78,7 @@ void TextInputModel::UpdateComposingText(const std::string& composing_text) {
   }
   DeleteSelected();
   text_.replace(composing_range_.start(), composing_range_.length(), text);
-  SetComposingLength(text.length());
+  composing_range_.set_length(text.length());
   selection_ = TextRange(composing_range_.end());
 }
 
@@ -110,16 +110,6 @@ bool TextInputModel::DeleteSelected() {
   return true;
 }
 
-void TextInputModel::SetComposingLength(size_t length) {
-  if (composing_range_.reversed()) {
-    size_t extent = composing_range_.extent();
-    composing_range_ = TextRange(extent + length, extent);
-  } else {
-    size_t base = composing_range_.base();
-    composing_range_ = TextRange(base, base + length);
-  }
-}
-
 void TextInputModel::AddCodePoint(char32_t c) {
   if (c <= 0xFFFF) {
     AddText(std::u16string({static_cast<char16_t>(c)}));
@@ -140,7 +130,7 @@ void TextInputModel::AddText(const std::u16string& text) {
     // Delete the current composing text, set the cursor to composing start.
     text_.erase(composing_range_.start(), composing_range_.length());
     selection_ = TextRange(composing_range_.start());
-    SetComposingLength(text.length());
+    composing_range_.set_length(text.length());
   }
   size_t position = selection_.position();
   text_.insert(position, text);
@@ -164,7 +154,7 @@ bool TextInputModel::Backspace() {
     text_.erase(position - count, count);
     selection_ = TextRange(position - count);
     if (composing_) {
-      SetComposingLength(composing_range_.length() - count);
+      composing_range_.set_length(composing_range_.length() - count);
     }
     return true;
   }
@@ -181,7 +171,7 @@ bool TextInputModel::Delete() {
     int count = IsLeadingSurrogate(text_.at(position)) ? 2 : 1;
     text_.erase(position, count);
     if (composing_) {
-      SetComposingLength(composing_range_.length() - count);
+      composing_range_.set_length(composing_range_.length() - count);
     }
     return true;
   }
@@ -224,7 +214,7 @@ bool TextInputModel::DeleteSurrounding(int offset_from_cursor, int count) {
 
   // Adjust composing range.
   if (composing_) {
-    SetComposingLength(composing_range_.length() - deleted_length);
+    composing_range_.set_length(composing_range_.length() - deleted_length);
   }
   return true;
 }

shell/platform/common/cpp/text_input_model.h

@@ -172,9 +172,6 @@ class TextInputModel {
   // reset to the start of the selected range.
   bool DeleteSelected();
 
-  // Adjusts the composing range to |length|.
-  void SetComposingLength(size_t length);
-
   // Returns the currently editable text range.
   //
   // In composing mode, returns the composing range; otherwise, returns a range

shell/platform/common/cpp/text_range.h

@@ -44,6 +44,18 @@ class TextRange {
   // Returns the length of the range.
   size_t length() const { return end() - start(); }
 
+  // Adjusts the length of the range relative to its start.
+  //
+  // For non-reversed ranges, the extent is adjusted relative to the base. For
+  // reversed ranges, the base is adjusted relative to the extent.
+  void set_length(size_t length) {
+    if (base_ > extent_) {
+      base_ = extent_ + length;
+    } else {
+      extent_ = base_ + length;
+    }
+  }
+
   // Returns true if the range is of length 0.
   bool collapsed() const { return base_ == extent_; }
 

shell/platform/common/cpp/text_range_unittests.cc

@@ -50,6 +50,34 @@ TEST(TextRange, TextRangeFromReversedRange) {
   EXPECT_FALSE(range.collapsed());
 }
 
+TEST(TextRange, SetLengthZero) {
+  TextRange range(3, 7);
+  range.set_length(0);
+  EXPECT_EQ(range.base(), size_t(3));
+  EXPECT_EQ(range.extent(), size_t(3));
+}
+
+TEST(TextRange, SetLengthNonZero) {
+  TextRange range(3, 7);
+  range.set_length(2);
+  EXPECT_EQ(range.base(), size_t(3));
+  EXPECT_EQ(range.extent(), size_t(5));
+}
+
+TEST(TextRange, SetLengthZeroReversed) {
+  TextRange range(7, 3);
+  range.set_length(0);
+  EXPECT_EQ(range.base(), size_t(3));
+  EXPECT_EQ(range.extent(), size_t(3));
+}
+
+TEST(TextRange, SetLengthNonZeroReversed) {
+  TextRange range(7, 3);
+  range.set_length(2);
+  EXPECT_EQ(range.base(), size_t(5));
+  EXPECT_EQ(range.extent(), size_t(3));
+}
+
 TEST(TextRange, ContainsPreStartPosition) {
   TextRange range(2, 6);
   EXPECT_FALSE(range.Contains(1));