1 files changed, 63 insertions, 43 deletions

diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 0e797d63bca9..ded4b12a046e 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -11,7 +11,25 @@ namespace nix {
 struct Sink 
 {
     virtual ~Sink() { }
-    virtual void operator () (const unsigned char * data, unsigned int len) = 0;
+    virtual void operator () (const unsigned char * data, size_t len) = 0;
+};
+
+
+/* A buffered abstract sink. */
+struct BufferedSink : Sink
+{
+    size_t bufSize, bufPos;
+    unsigned char * buffer;
+
+    BufferedSink(size_t bufSize = 32 * 1024)
+        : bufSize(bufSize), bufPos(0), buffer(0) { }
+    ~BufferedSink();
+
+    void operator () (const unsigned char * data, size_t len);
+    
+    void flush();
+    
+    virtual void write(const unsigned char * data, size_t len) = 0;
 };
 
 
@@ -20,49 +38,55 @@ struct Source
 {
     virtual ~Source() { }
     
-    /* The callee should store exactly *len bytes in the buffer
-       pointed to by data.  It should block if that much data is not
-       yet available, or throw an error if it is not going to be
-       available. */
-    virtual void operator () (unsigned char * data, unsigned int len) = 0;
+    /* Store exactly ‘len’ bytes in the buffer pointed to by ‘data’.
+       It blocks until all the requested data is available, or throws
+       an error if it is not going to be available.   */
+    void operator () (unsigned char * data, size_t len);
+
+    /* Store up to ‘len’ in the buffer pointed to by ‘data’, and
+       return the number of bytes stored.  If blocks until at least
+       one byte is available. */
+    virtual size_t read(unsigned char * data, size_t len) = 0;
 };
 
 
-/* A sink that writes data to a file descriptor. */
-struct FdSink : Sink
+/* A buffered abstract source. */
+struct BufferedSource : Source
 {
-    int fd;
+    size_t bufSize, bufPosIn, bufPosOut;
+    unsigned char * buffer;
 
-    FdSink()
-    {
-        fd = -1;
-    }
+    BufferedSource(size_t bufSize = 32 * 1024)
+        : bufSize(bufSize), bufPosIn(0), bufPosOut(0), buffer(0) { }
+    ~BufferedSource();
     
-    FdSink(int fd) 
-    {
-        this->fd = fd;
-    }
+    size_t read(unsigned char * data, size_t len);
     
-    void operator () (const unsigned char * data, unsigned int len);
+    /* Underlying read call, to be overriden. */
+    virtual size_t readUnbuffered(unsigned char * data, size_t len) = 0;
 };
 
 
-/* A source that reads data from a file descriptor. */
-struct FdSource : Source
+/* A sink that writes data to a file descriptor. */
+struct FdSink : BufferedSink
 {
     int fd;
 
-    FdSource()
-    {
-        fd = -1;
-    }
+    FdSink() : fd(-1) { }
+    FdSink(int fd) : fd(fd) { }
+    ~FdSink();
     
-    FdSource(int fd) 
-    {
-        this->fd = fd;
-    }
-    
-    void operator () (unsigned char * data, unsigned int len);
+    void write(const unsigned char * data, size_t len);
+};
+
+
+/* A source that reads data from a file descriptor. */
+struct FdSource : BufferedSource
+{
+    int fd;
+    FdSource() : fd(-1) { }
+    FdSource(int fd) : fd(fd) { }
+    size_t readUnbuffered(unsigned char * data, size_t len);
 };
 
 
@@ -70,7 +94,7 @@ struct FdSource : Source
 struct StringSink : Sink
 {
     string s;
-    virtual void operator () (const unsigned char * data, unsigned int len)
+    void operator () (const unsigned char * data, size_t len)
     {
         s.append((const char *) data, len);
     }
@@ -81,29 +105,25 @@ struct StringSink : Sink
 struct StringSource : Source
 {
     const string & s;
-    unsigned int pos;
+    size_t pos;
     StringSource(const string & _s) : s(_s), pos(0) { }
-    virtual void operator () (unsigned char * data, unsigned int len)
-    {
-        s.copy((char *) data, len, pos);
-        pos += len;
-        if (pos > s.size())
-            throw Error("end of string reached");
-    }
+    size_t read(unsigned char * data, size_t len);    
 };
 
 
-void writePadding(unsigned int len, Sink & sink);
+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);
+template<class T> void writeStrings(const T & ss, Sink & sink);
 
-void readPadding(unsigned int len, Source & source);
+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);
+template<class T> T readStrings(Source & source);
 
 
 MakeError(SerialisationError, Error)