[inspector] restore provisional breakpoints smarter

src/inspector/v8-debugger-script.cc

Index: src/inspector/v8-debugger-script.cc
diff --git a/src/inspector/v8-debugger-script.cc b/src/inspector/v8-debugger-script.cc
index 200cdc71a26da41ae8bba76d30144ad5a2eca0f7..e7fed32500cceb68ffc7afa8ad7ad736ac28d8bf 100644
--- a/src/inspector/v8-debugger-script.cc
+++ b/src/inspector/v8-debugger-script.cc
@@ -5,6 +5,7 @@
 #include "src/inspector/v8-debugger-script.h"
 
 #include "src/inspector/inspected-context.h"
+#include "src/inspector/search-util.h"
 #include "src/inspector/string-util.h"
 #include "src/inspector/wasm-translation.h"
 
@@ -154,10 +155,11 @@ class ActualScript : public V8DebuggerScript {
     return m_sourceMappingURL;
   }
 
-  String16 source(v8::Isolate* isolate) const override {
+  String16 source() const override {
+    v8::HandleScope scope(m_isolate);
     if (!m_sourceObj.IsEmpty())
-      return toProtocolString(m_sourceObj.Get(isolate));
-    return V8DebuggerScript::source(isolate);
+      return toProtocolString(m_sourceObj.Get(m_isolate));
+    return V8DebuggerScript::source();
   }
 
   void setSourceMappingURL(const String16& sourceMappingURL) override {
@@ -165,7 +167,8 @@ class ActualScript : public V8DebuggerScript {
   }
 
   void setSource(v8::Local<v8::String> source) override {
-    m_source = String16();
+    std::vector<int> empty;
+    m_lineEndings.swap(empty);
     m_sourceObj.Reset(m_isolate, source);
     m_hash = String16();
   }
@@ -184,6 +187,12 @@ class ActualScript : public V8DebuggerScript {
   }
 
  private:
+  void calculateLineEndings() override {
+    if (!m_lineEndings.empty()) return;
+    v8::HandleScope scope(m_isolate);
+    m_script.Get(m_isolate)->LineEnds().swap(m_lineEndings);
+  }
+
   String16 GetNameOrSourceUrl(v8::Local<v8::debug::Script> script) {
     v8::Local<v8::String> name;
     if (script->Name().ToLocal(&name) || script->SourceURL().ToLocal(&name))
@@ -259,6 +268,20 @@ class WasmVirtualScript : public V8DebuggerScript {
   void resetBlackboxedStateCache() override {}
 
  private:
+  void calculateLineEndings() override {

[alph, 2017/02/08 02:02:08]

ensureLineEndings?

+    if (!m_lineEndings.empty()) return;
+    String16 text = source();
+    const String16 lineEndString = "\n";
+    size_t start = 0;
+    while (start < text.length()) {
+      size_t lineEnd = text.find(lineEndString, start);

[alph, 2017/02/08 02:02:08]

nit: find(UChar) should be faster.

+      if (lineEnd == String16::kNotFound) break;
+      m_lineEndings.push_back(static_cast<int>(lineEnd));
+      start = lineEnd + 1;
+    }
+    m_lineEndings.push_back(static_cast<int>(text.length()));
+  }
+
   static const String16& emptyString() {
     static const String16 singleEmptyString;
     return singleEmptyString;
@@ -296,8 +319,8 @@ const String16& V8DebuggerScript::sourceURL() const {
   return m_sourceURL.isEmpty() ? m_url : m_sourceURL;
 }
 
-const String16& V8DebuggerScript::hash(v8::Isolate* isolate) const {
-  if (m_hash.isEmpty()) m_hash = calculateHash(source(isolate));
+const String16& V8DebuggerScript::hash() const {
+  if (m_hash.isEmpty()) m_hash = calculateHash(source());
   DCHECK(!m_hash.isEmpty());
   return m_hash;
 }
@@ -306,4 +329,19 @@ void V8DebuggerScript::setSourceURL(const String16& sourceURL) {
   m_sourceURL = sourceURL;
 }
 
+String16 V8DebuggerScript::lineAt(int lineNumberWithOffset, int maxLength) {
+  String16 sourceStr = source();
+  calculateLineEndings();
+  int lineNumber = lineNumberWithOffset - m_startLine;
+  if (lineNumber >= static_cast<int>(m_lineEndings.size()) || lineNumber < 0)

[alph, 2017/02/08 02:02:08]

{}

+    return String16();
+  size_t lineEnd = m_lineEndings[lineNumber];
+  size_t lineStart = lineNumber > 0 ? m_lineEndings[lineNumber - 1] + 1 : 0;
+  String16 line = sourceStr.substring(lineStart, lineEnd - lineStart);
+  if (line.length() && line[line.length() - 1] == '\r')

[alph, 2017/02/08 02:02:08]

{}

+    line = line.substring(0, line.length() - 1);
+  if (maxLength) line = line.substring(0, maxLength);
+  return line;
+}
+
 }  // namespace v8_inspector