Magic-Mirror/gecko-dev
1
0
Fork 0
mirror of https://github.com/mozilla/gecko-dev.git synced 2024-11-23 21:01:08 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Bug 1247359 - micro-optimize the common case of String{Begins,End}With; r=erahm

Browse Source 
StringBeginsWith (resp. StringEndsWith) takes a defaulted
nsStringComparator object for doing comparisons.  The flexibility this
affords is great, but the cost is not: nsStringComparator has virtual
methods, so initializing that defaulted object (at every callsite)
requires a temporary object whose vtable must be initialized.

Since the overwhemingly common case is to use the default comparator
anyway, we should not use defaulted arguments and instead provide the
default comparator/user-provided comparator cases as separate overloads.
This change eliminates the virtual call for the majority of callsites
and reduces codesize as well.
This commit is contained in:
Nathan Froyd 2016-02-10 14:31:06 -05:00
parent 6a5930b454
commit 9a2523bcc3
2 changed files with 52 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
xpcom/string/nsReadableUtils.cpp
View File

@ -1026,6 +1026,17 @@ CountCharInReadable(const nsACString& aStr, char aChar)
return count;
}
bool
StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring)
{
nsAString::size_type src_len = aSource.Length(),
sub_len = aSubstring.Length();
if (sub_len > src_len) {
return false;
}
return Substring(aSource, 0, sub_len).Equals(aSubstring);
}
bool
StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring,
const nsStringComparator& aComparator)
@ -1038,6 +1049,17 @@ StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring,
return Substring(aSource, 0, sub_len).Equals(aSubstring, aComparator);
}
bool
StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring)
{
nsACString::size_type src_len = aSource.Length(),
sub_len = aSubstring.Length();
if (sub_len > src_len) {
return false;
}
return Substring(aSource, 0, sub_len).Equals(aSubstring);
}
bool
StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring,
const nsCStringComparator& aComparator)
@ -1050,6 +1072,17 @@ StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring,
return Substring(aSource, 0, sub_len).Equals(aSubstring, aComparator);
}
bool
StringEndsWith(const nsAString& aSource, const nsAString& aSubstring)
{
nsAString::size_type src_len = aSource.Length(),
sub_len = aSubstring.Length();
if (sub_len > src_len) {
return false;
}
return Substring(aSource, src_len - sub_len, sub_len).Equals(aSubstring);
}
bool
StringEndsWith(const nsAString& aSource, const nsAString& aSubstring,
const nsStringComparator& aComparator)
@ -1063,6 +1096,17 @@ StringEndsWith(const nsAString& aSource, const nsAString& aSubstring,
aComparator);
}
bool
StringEndsWith(const nsACString& aSource, const nsACString& aSubstring)
{
nsACString::size_type src_len = aSource.Length(),
sub_len = aSubstring.Length();
if (sub_len > src_len) {
return false;
}
return Substring(aSource, src_len - sub_len, sub_len).Equals(aSubstring);
}
bool
StringEndsWith(const nsACString& aSource, const nsACString& aSubstring,
const nsCStringComparator& aComparator)

16
xpcom/string/nsReadableUtils.h
View File

@ -386,18 +386,18 @@ uint32_t CountCharInReadable(const nsAString& aStr,
uint32_t CountCharInReadable(const nsACString& aStr,
char aChar);
bool StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring);
bool StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring,
const nsStringComparator& aComparator =
nsDefaultStringComparator());
const nsStringComparator& aComparator);
bool StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring);
bool StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring,
const nsCStringComparator& aComparator =
nsDefaultCStringComparator());
const nsCStringComparator& aComparator);
bool StringEndsWith(const nsAString& aSource, const nsAString& aSubstring);
bool StringEndsWith(const nsAString& aSource, const nsAString& aSubstring,
const nsStringComparator& aComparator =
nsDefaultStringComparator());
const nsStringComparator& aComparator);
bool StringEndsWith(const nsACString& aSource, const nsACString& aSubstring);
bool StringEndsWith(const nsACString& aSource, const nsACString& aSubstring,
const nsCStringComparator& aComparator =
nsDefaultCStringComparator());
const nsCStringComparator& aComparator);
const nsAFlatString& EmptyString();
const nsAFlatCString& EmptyCString();