[url] Reserve output buffer for various URL parsing paths

url/gurl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "url/gurl.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <ostream>
@@ skipping 90 matching lines @@
 }
 
 GURL::GURL(std::string canonical_spec, const url::Parsed& parsed, bool is_valid)
     : spec_(std::move(canonical_spec)), is_valid_(is_valid), parsed_(parsed) {
   InitializeFromCanonicalSpec();
 }
 
 template<typename STR>
 void GURL::InitCanonical(base::BasicStringPiece<STR> input_spec,
                          bool trim_path_end) {
-  // Reserve enough room in the output for the input, plus some extra so that
-  // we have room if we have to escape a few things without reallocating.
-  spec_.reserve(input_spec.size() + 32);
   url::StdStringCanonOutput output(&spec_);
   is_valid_ = url::Canonicalize(
       input_spec.data(), static_cast<int>(input_spec.length()), trim_path_end,
       NULL, &output, &parsed_);
 
   output.Complete();  // Must be done before using string.
   if (is_valid_ && SchemeIsFileSystem()) {
     inner_url_.reset(new GURL(spec_.data(), parsed_.Length(),
                               *parsed_.inner_parsed(), true));
   }
@@ skipping 67 matching lines @@
   return spec_ > other.spec_;
 }
 
 // Note: code duplicated below (it's inconvenient to use a template here).
 GURL GURL::Resolve(const std::string& relative) const {
   // Not allowed for invalid URLs.
   if (!is_valid_)
     return GURL();
 
   GURL result;
-
-  // Reserve enough room in the output for the input, plus some extra so that
-  // we have room if we have to escape a few things without reallocating.
-  result.spec_.reserve(spec_.size() + 32);
   url::StdStringCanonOutput output(&result.spec_);
-
   if (!url::ResolveRelative(spec_.data(), static_cast<int>(spec_.length()),
                             parsed_, relative.data(),
                             static_cast<int>(relative.length()),
                             nullptr, &output, &result.parsed_)) {
     // Error resolving, return an empty URL.
     return GURL();
   }
 
   output.Complete();
   result.is_valid_ = true;
   if (result.SchemeIsFileSystem()) {
     result.inner_url_.reset(
         new GURL(result.spec_.data(), result.parsed_.Length(),
                  *result.parsed_.inner_parsed(), true));
   }
   return result;
 }
 
 // Note: code duplicated above (it's inconvenient to use a template here).
 GURL GURL::Resolve(const base::string16& relative) const {
   // Not allowed for invalid URLs.
   if (!is_valid_)
     return GURL();
 
   GURL result;
-
-  // Reserve enough room in the output for the input, plus some extra so that
-  // we have room if we have to escape a few things without reallocating.
-  result.spec_.reserve(spec_.size() + 32);
   url::StdStringCanonOutput output(&result.spec_);
-
   if (!url::ResolveRelative(spec_.data(), static_cast<int>(spec_.length()),
                             parsed_, relative.data(),
                             static_cast<int>(relative.length()),
                             nullptr, &output, &result.parsed_)) {
     // Error resolving, return an empty URL.
     return GURL();
   }
 
   output.Complete();
   result.is_valid_ = true;
   if (result.SchemeIsFileSystem()) {
     result.inner_url_.reset(
         new GURL(result.spec_.data(), result.parsed_.Length(),
                  *result.parsed_.inner_parsed(), true));
   }
   return result;
 }
 
 // Note: code duplicated below (it's inconvenient to use a template here).
 GURL GURL::ReplaceComponents(
     const url::Replacements<char>& replacements) const {
   GURL result;
 
   // Not allowed for invalid URLs.
   if (!is_valid_)
     return GURL();
 
-  // Reserve enough room in the output for the input, plus some extra so that
-  // we have room if we have to escape a few things without reallocating.
-  result.spec_.reserve(spec_.size() + 32);
   url::StdStringCanonOutput output(&result.spec_);
-
   result.is_valid_ = url::ReplaceComponents(
       spec_.data(), static_cast<int>(spec_.length()), parsed_, replacements,
       NULL, &output, &result.parsed_);
 
   output.Complete();
   if (result.is_valid_ && result.SchemeIsFileSystem()) {
     result.inner_url_.reset(new GURL(result.spec_.data(),
                                      result.parsed_.Length(),
                                      *result.parsed_.inner_parsed(), true));
   }
   return result;
 }
 
 // Note: code duplicated above (it's inconvenient to use a template here).
 GURL GURL::ReplaceComponents(
     const url::Replacements<base::char16>& replacements) const {
   GURL result;
 
   // Not allowed for invalid URLs.
   if (!is_valid_)
     return GURL();
 
-  // Reserve enough room in the output for the input, plus some extra so that
-  // we have room if we have to escape a few things without reallocating.
-  result.spec_.reserve(spec_.size() + 32);
   url::StdStringCanonOutput output(&result.spec_);
-
   result.is_valid_ = url::ReplaceComponents(
       spec_.data(), static_cast<int>(spec_.length()), parsed_, replacements,
       NULL, &output, &result.parsed_);
 
   output.Complete();
   if (result.is_valid_ && result.SchemeIsFileSystem()) {
     result.inner_url_.reset(new GURL(result.spec_.data(),
                                      result.parsed_.Length(),
                                      *result.parsed_.inner_parsed(), true));
   }
@@ skipping 201 matching lines @@
 }
 
 bool operator==(const GURL& x, const base::StringPiece& spec) {
   DCHECK_EQ(GURL(spec).possibly_invalid_spec(), spec);
   return x.possibly_invalid_spec() == spec;
 }
 
 bool operator!=(const GURL& x, const base::StringPiece& spec) {
   return !(x == spec);
 }