Author: eelco
Date: Fri Dec 16 21:29:46 2011
New Revision: 30943
URL: https://nixos.org/websvn/nix/?rev=30943&sc=1
Log:
* Avoid expensive conversions from char arrays to STL strings.
Modified:
nix/trunk/src/libutil/serialise.cc
nix/trunk/src/libutil/serialise.hh
nix/trunk/src/nix-worker/nix-worker.cc
Modified: nix/trunk/src/libutil/serialise.cc
==============================================================================
--- nix/trunk/src/libutil/serialise.cc Fri Dec 16 19:55:48 2011 (r30942)
+++ nix/trunk/src/libutil/serialise.cc Fri Dec 16 21:29:46 2011 (r30943)
@@ -149,15 +149,20 @@
}
-void writeString(const string & s, Sink & sink)
+void writeString(const unsigned char * buf, size_t len, Sink & sink)
{
- size_t len = s.length();
writeInt(len, sink);
- sink((const unsigned char *) s.c_str(), len);
+ sink(buf, len);
writePadding(len, sink);
}
+void writeString(const string & s, Sink & sink)
+{
+ writeString((const unsigned char *) s.c_str(), s.size(), sink);
+}
+
+
void writeStringSet(const StringSet & ss, Sink & sink)
{
writeInt(ss.size(), sink);
@@ -208,6 +213,16 @@
}
+size_t readString(unsigned char * buf, size_t max, Source & source)
+{
+ size_t len = readInt(source);
+ if (len > max) throw Error("string is too long");
+ source(buf, len);
+ readPadding(len, source);
+ return len;
+}
+
+
string readString(Source & source)
{
size_t len = readInt(source);
Modified: nix/trunk/src/libutil/serialise.hh
==============================================================================
--- nix/trunk/src/libutil/serialise.hh Fri Dec 16 19:55:48 2011 (r30942)
+++ nix/trunk/src/libutil/serialise.hh Fri Dec 16 21:29:46 2011 (r30943)
@@ -114,12 +114,14 @@
void writePadding(size_t len, Sink & sink);
void writeInt(unsigned int n, Sink & sink);
void writeLongLong(unsigned long long n, Sink & sink);
+void writeString(const unsigned char * buf, size_t len, Sink & sink);
void writeString(const string & s, Sink & sink);
void writeStringSet(const StringSet & ss, Sink & sink);
void readPadding(size_t len, Source & source);
unsigned int readInt(Source & source);
unsigned long long readLongLong(Source & source);
+size_t readString(unsigned char * buf, size_t max, Source & source);
string readString(Source & source);
StringSet readStringSet(Source & source);
Modified: nix/trunk/src/nix-worker/nix-worker.cc
==============================================================================
--- nix/trunk/src/nix-worker/nix-worker.cc Fri Dec 16 19:55:48 2011
(r30942)
+++ nix/trunk/src/nix-worker/nix-worker.cc Fri Dec 16 21:29:46 2011
(r30943)
@@ -56,7 +56,7 @@
if (canSendStderr && myPid == getpid()) {
try {
writeInt(STDERR_NEXT, to);
- writeString(string((char *) buf, count), to);
+ writeString(buf, count, to);
to.flush();
} catch (...) {
/* Write failed; that means that the other side is
@@ -205,7 +205,7 @@
virtual void operator () (const unsigned char * data, size_t len)
{
writeInt(STDERR_WRITE, to);
- writeString(string((const char *) data, len), to);
+ writeString(data, len, to);
}
};
@@ -224,16 +224,11 @@
writeInt(STDERR_READ, to);
writeInt(len, to);
to.flush();
- string s = readString(from); // !!! inefficient
+ size_t n = readString(data, len, from);
startWork();
-
- if (s.empty()) throw EndOfFile("unexpected end-of-file");
- if (s.size() > len) throw Error("client sent too much data");
-
- memcpy(data, (const unsigned char *) s.c_str(), s.size());
-
- return s.size();
+ if (n == 0) throw EndOfFile("unexpected end-of-file");
+ return n;
}
};
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