commit 60dfe9b0a6008af3ecb7f9af77202c019d89c9fa
author Lei Zhang <thestig@chromium.org> Thu Sep 21 23:07:53 2023 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Thu Sep 21 23:07:53 2023 +0000
tree aa0a36179eb223c226bd178ec3ae521b0f42bae4
parent 5036903677a2ce22739c263c7c09f81d5c5a7662

Avoid some unnecessary SharedCopyOnWrite copies

Per suggestion on the bug, avoid copying in various SharedCopyOnWrite
objects if the copy is going to have the same value as the existing
copy. This just gets some of the low hanging fruits.

Bug: pdfium:1917
Change-Id: I587c26cdcdf580480419a4b4767a71c8b7c8230e
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/112070
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

core/fpdfapi/page/cpdf_colorstate.cpp

diff --git a/core/fpdfapi/page/cpdf_colorstate.cpp b/core/fpdfapi/page/cpdf_colorstate.cpp
index 8d94627..dde0c29 100644
--- a/core/fpdfapi/page/cpdf_colorstate.cpp
+++ b/core/fpdfapi/page/cpdf_colorstate.cpp
@@ -33,7 +33,9 @@
 }
 
 void CPDF_ColorState::SetFillColorRef(FX_COLORREF colorref) {
-  m_Ref.GetPrivateCopy()->m_FillColorRef = colorref;
+  if (!m_Ref || GetFillColorRef() != colorref) {
+    m_Ref.GetPrivateCopy()->m_FillColorRef = colorref;
+  }
 }
 
 FX_COLORREF CPDF_ColorState::GetStrokeColorRef() const {
@@ -41,7 +43,9 @@
 }
 
 void CPDF_ColorState::SetStrokeColorRef(FX_COLORREF colorref) {
-  m_Ref.GetPrivateCopy()->m_StrokeColorRef = colorref;
+  if (!m_Ref || GetStrokeColorRef() != colorref) {
+    m_Ref.GetPrivateCopy()->m_StrokeColorRef = colorref;
+  }
 }
 
 const CPDF_Color* CPDF_ColorState::GetFillColor() const {

core/fpdfapi/page/cpdf_generalstate.cpp

diff --git a/core/fpdfapi/page/cpdf_generalstate.cpp b/core/fpdfapi/page/cpdf_generalstate.cpp
index 4c1e692..c67d30c 100644
--- a/core/fpdfapi/page/cpdf_generalstate.cpp
+++ b/core/fpdfapi/page/cpdf_generalstate.cpp
@@ -123,7 +123,9 @@
 }
 
 void CPDF_GeneralState::SetBlendType(BlendMode type) {
-  m_Ref.GetPrivateCopy()->m_BlendType = type;
+  if (GetBlendType() != type) {
+    m_Ref.GetPrivateCopy()->m_BlendType = type;
+  }
 }
 
 float CPDF_GeneralState::GetFillAlpha() const {
@@ -132,7 +134,9 @@
 }
 
 void CPDF_GeneralState::SetFillAlpha(float alpha) {
-  m_Ref.GetPrivateCopy()->m_FillAlpha = alpha;
+  if (GetFillAlpha() != alpha) {
+    m_Ref.GetPrivateCopy()->m_FillAlpha = alpha;
+  }
 }
 
 float CPDF_GeneralState::GetStrokeAlpha() const {
@@ -141,7 +145,9 @@
 }
 
 void CPDF_GeneralState::SetStrokeAlpha(float alpha) {
-  m_Ref.GetPrivateCopy()->m_StrokeAlpha = alpha;
+  if (GetStrokeAlpha() != alpha) {
+    m_Ref.GetPrivateCopy()->m_StrokeAlpha = alpha;
+  }
 }
 
 RetainPtr<const CPDF_Dictionary> CPDF_GeneralState::GetSoftMask() const {

core/fpdfapi/page/cpdf_textstate.cpp

diff --git a/core/fpdfapi/page/cpdf_textstate.cpp b/core/fpdfapi/page/cpdf_textstate.cpp
index 6e48b87..a24eb04 100644
--- a/core/fpdfapi/page/cpdf_textstate.cpp
+++ b/core/fpdfapi/page/cpdf_textstate.cpp
@@ -34,7 +34,9 @@
 }
 
 void CPDF_TextState::SetFontSize(float size) {
-  m_Ref.GetPrivateCopy()->m_FontSize = size;
+  if (!m_Ref || GetFontSize() != size) {
+    m_Ref.GetPrivateCopy()->m_FontSize = size;
+  }
 }
 
 pdfium::span<const float> CPDF_TextState::GetMatrix() const {
@@ -50,7 +52,9 @@
 }
 
 void CPDF_TextState::SetCharSpace(float sp) {
-  m_Ref.GetPrivateCopy()->m_CharSpace = sp;
+  if (!m_Ref || GetCharSpace() != sp) {
+    m_Ref.GetPrivateCopy()->m_CharSpace = sp;
+  }
 }
 
 float CPDF_TextState::GetWordSpace() const {
@@ -58,7 +62,9 @@
 }
 
 void CPDF_TextState::SetWordSpace(float sp) {
-  m_Ref.GetPrivateCopy()->m_WordSpace = sp;
+  if (!m_Ref || GetWordSpace() != sp) {
+    m_Ref.GetPrivateCopy()->m_WordSpace = sp;
+  }
 }
 
 float CPDF_TextState::GetFontSizeH() const {
@@ -70,7 +76,9 @@
 }
 
 void CPDF_TextState::SetTextMode(TextRenderingMode mode) {
-  m_Ref.GetPrivateCopy()->m_TextMode = mode;
+  if (!m_Ref || GetTextMode() != mode) {
+    m_Ref.GetPrivateCopy()->m_TextMode = mode;
+  }
 }
 
 pdfium::span<const float> CPDF_TextState::GetCTM() const {