[Extensions] Reduce string copy in renderer/ UserScript.
Before passing StringPiece script (JS/CSS) content to blink (to create
WebString or WebScriptSource), we sometimes unnecessarily created
std::string. This CL removes the intermediate state.
Greasemonkey scripts still require the intermediate std::string to
pad it with header and tail though. Use reserve and
StringPiece.appendToString() in that case to at least do that
efficiently.
BUG=622464
Test=No visible change.
Review-Url: https://codereview.chromium.org/2250263004
Cr-Commit-Position: refs/heads/master@{#412946}
diff --git a/extensions/renderer/user_script_injector.cc b/extensions/renderer/user_script_injector.cc
index 21a59ea..0b2184a 100644
--- a/extensions/renderer/user_script_injector.cc
+++ b/extensions/renderer/user_script_injector.cc
@@ -203,20 +203,31 @@
DCHECK_EQ(script_->run_location(), run_location);
const UserScript::FileList& js_scripts = script_->js_scripts();
-
+ sources.reserve(js_scripts.size());
for (UserScript::FileList::const_iterator iter = js_scripts.begin();
iter != js_scripts.end();
++iter) {
- std::string content = iter->GetContent().as_string();
-
- // We add this dumb function wrapper for user scripts to emulate what
- // Greasemonkey does.
+ base::StringPiece script_content = iter->GetContent();
+ blink::WebString source;
if (script_->emulate_greasemonkey()) {
- content.insert(0, kUserScriptHead);
- content += kUserScriptTail;
+ // We add this dumb function wrapper for user scripts to emulate what
+ // Greasemonkey does. |script_content| becomes:
+ // concat(kUserScriptHead, script_content, kUserScriptTail).
+ std::string content;
+ content.reserve(strlen(kUserScriptHead) + script_content.length() +
+ strlen(kUserScriptTail));
+ content.append(kUserScriptHead);
+ script_content.AppendToString(&content);
+ content.append(kUserScriptTail);
+ // TODO(lazyboy): |content| is copied to |source|, should be avoided.
+ // Investigate if we can leverage WebString's cheap copying mechanism
+ // somehow.
+ source = blink::WebString::fromUTF8(content);
+ } else {
+ source = blink::WebString::fromUTF8(script_content.data(),
+ script_content.length());
}
- sources.push_back(blink::WebScriptSource(
- blink::WebString::fromUTF8(content), iter->url()));
+ sources.push_back(blink::WebScriptSource(source, iter->url()));
}
// Emulate Greasemonkey API for scripts that were converted to extension
@@ -227,19 +238,22 @@
return sources;
}
-std::vector<std::string> UserScriptInjector::GetCssSources(
+std::vector<blink::WebString> UserScriptInjector::GetCssSources(
UserScript::RunLocation run_location) const {
DCHECK_EQ(UserScript::DOCUMENT_START, run_location);
- std::vector<std::string> sources;
+ std::vector<blink::WebString> sources;
if (!script_)
return sources;
const UserScript::FileList& css_scripts = script_->css_scripts();
+ sources.reserve(css_scripts.size());
for (UserScript::FileList::const_iterator iter = css_scripts.begin();
iter != css_scripts.end();
++iter) {
- sources.push_back(iter->GetContent().as_string());
+ base::StringPiece css_content = iter->GetContent();
+ sources.push_back(
+ blink::WebString::fromUTF8(css_content.data(), css_content.length()));
}
return sources;
}
