event/BufferedSocket: pass writable pointer to OnSocketInput()

Remove the const_cast from HttpdClient.cxx, and avoid one allocation
in ClientRead.cxx.

src/ClientInternal.hxx

@@ -111,8 +111,7 @@ public:
 
 private:
 	/* virtual methods from class BufferedSocket */
-	virtual InputResult OnSocketInput(const void *data,
-					  size_t length) override;
+	virtual InputResult OnSocketInput(void *data, size_t length) override;
 	virtual void OnSocketError(Error &&error) override;
 	virtual void OnSocketClosed() override;
 

src/ClientRead.cxx

@@ -22,27 +22,25 @@
 #include "Main.hxx"
 #include "event/Loop.hxx"
 
-#include <glib.h>
-
 #include <assert.h>
 #include <string.h>
 
 BufferedSocket::InputResult
-Client::OnSocketInput(const void *data, size_t length)
+Client::OnSocketInput(void *data, size_t length)
 {
-	const char *p = (const char *)data;
-	const char *newline = (const char *)memchr(p, '\n', length);
+	char *p = (char *)data;
+	char *newline = (char *)memchr(p, '\n', length);
 	if (newline == NULL)
 		return InputResult::MORE;
 
 	TimeoutMonitor::ScheduleSeconds(client_timeout);
 
-	char *line = g_strndup(p, newline - p);
+	/* terminate the string at the end of the line */
+	*newline = 0;
+
 	BufferedSocket::ConsumeInput(newline + 1 - p);
 
-	enum command_return result = client_process_line(this, line);
-	g_free(line);
-
+	enum command_return result = client_process_line(this, p);
 	switch (result) {
 	case COMMAND_RETURN_OK:
 	case COMMAND_RETURN_IDLE:

src/event/BufferedSocket.hxx

@@ -101,7 +101,15 @@ protected:
 		CLOSED,
 	};
 
-	virtual InputResult OnSocketInput(const void *data, size_t length) = 0;
+	/**
+	 * Data has been received on the socket.
+	 *
+	 * @param data a pointer to the beginning of the buffer; the
+	 * buffer may be modified by the method while it processes the
+	 * data
+	 */
+	virtual InputResult OnSocketInput(void *data, size_t length) = 0;
+
 	virtual void OnSocketError(Error &&error) = 0;
 	virtual void OnSocketClosed() = 0;
 

src/output/HttpdClient.cxx

@@ -402,7 +402,7 @@ HttpdClient::OnSocketReady(unsigned flags)
 }
 
 BufferedSocket::InputResult
-HttpdClient::OnSocketInput(const void *data, size_t length)
+HttpdClient::OnSocketInput(void *data, size_t length)
 {
 	if (state == RESPONSE) {
 		LogWarning(httpd_output_domain,
@@ -411,8 +411,8 @@ HttpdClient::OnSocketInput(const void *data, size_t length)
 		return InputResult::CLOSED;
 	}
 
-	const char *line = (const char *)data;
-	const char *newline = (const char *)memchr(line, '\n', length);
+	char *line = (char *)data;
+	char *newline = (char *)memchr(line, '\n', length);
 	if (newline == nullptr)
 		return InputResult::MORE;
 
@@ -421,9 +421,8 @@ HttpdClient::OnSocketInput(const void *data, size_t length)
 	if (newline > line && newline[-1] == '\r')
 		--newline;
 
-	/* terminate the string at the end of the line; the const_cast
-	   is a dirty hack */
-	*const_cast<char *>(newline) = 0;
+	/* terminate the string at the end of the line */
+	*newline = 0;
 
 	if (!HandleLine(line)) {
 		assert(state == RESPONSE);

src/output/HttpdClient.hxx

@@ -177,8 +177,7 @@ public:
 
 protected:
 	virtual bool OnSocketReady(unsigned flags) override;
-	virtual InputResult OnSocketInput(const void *data,
-					  size_t length) override;
+	virtual InputResult OnSocketInput(void *data, size_t length) override;
 	virtual void OnSocketError(Error &&error) override;
 	virtual void OnSocketClosed() override;
 };