From ce1f37aae46ea95020d7b865f7a80e8abdfad0d8 Mon Sep 17 00:00:00 2001
From: Michael Krelin <hacker@klever.net>
Date: Sat, 29 Jan 2005 21:21:05 +0000
Subject: initial commit into repository

---
(limited to 'lib/component_so.cc')

diff --git a/lib/component_so.cc b/lib/component_so.cc
new file mode 100644
index 0000000..57cce01
--- a/dev/null
+++ b/lib/component_so.cc
@@ -0,0 +1,112 @@
+#ifdef USE_PCH
+ #include "pch.h"
+#else
+ #include <unistd.h>
+ #include <dlfcn.h>
+ #include <iostream>
+ #include <cassert>
+ #include <stdexcept>
+ using namespace std;
+ #include "sitecing/component_so.h"
+ #include "sitecing/sitecing_util.h"
+#endif
+
+namespace sitecing {
+
+    /*
+     * component_so
+     */
+
+    component_so::component_so(const string& soname)
+	: dl(NULL), sofile(soname) {
+	    if(stat(sofile.c_str(),&stso))
+		throw konforka::exception(CODEPOINT,"failed to stat() shared object");
+	    file_lock lock(sofile+".lock");
+	    dl = dlopen(sofile.c_str(),RTLD_LAZY);
+	    lock.unlock();
+	    if(!dl)
+		throw konforka::exception(CODEPOINT,"failed to dlopen: "+string(dlerror()));
+	    egg = (egg_t)dlsym(dl,"_egg");
+	    if(!egg)
+		throw konforka::exception(CODEPOINT,"failed to dlsym: "+string(dlerror()));
+	}
+    component_so::~component_so() {
+	for(free_chickens_t::iterator i=chickens_free.begin();i!=chickens_free.end();i++)
+	    delete *i;
+	chickens_free.clear();
+	if(!chickens_used.empty())
+	    throw konforka::exception(CODEPOINT,"attempt to destroy the component in use");
+	dlclose(dl);
+    }
+
+    bool component_so::is_uptodate() const {
+	struct stat st;
+	if(stat(sofile.c_str(),&st))
+	    throw konforka::exception(CODEPOINT,"failed to stat() shared object");
+	return stso.st_mtime==st.st_mtime;
+    }
+
+    acomponent* component_so::allocate_chicken() {
+	acomponent *rv;
+	if(!chickens_free.empty()) {
+	    rv = chickens_free.front();
+	    chickens_free.pop_front();
+	}else{
+	    rv = (*egg)();
+	}
+	assert(chickens_used.find(rv)==chickens_used.end());
+	chickens_used[rv]=1;
+	return rv;
+    }
+
+    void component_so::allocate_chicken(acomponent* ac) {
+	used_chickens_t::iterator i = chickens_used.find(ac);
+	if(i!=chickens_used.end()) {
+	    i->second++;
+	}else{
+	    free_chickens_t::iterator i;
+	    for(i=chickens_free.begin();*i!=ac && i!=chickens_free.end();i++);
+	    if(i==chickens_free.end())
+		throw konforka::exception(CODEPOINT,"hens rarely adopt chickens");
+	    chickens_free.erase(i);
+	    chickens_used[ac]=1;
+	}
+    }
+
+    void component_so::deallocate_chicken(acomponent* ac) {
+	used_chickens_t::iterator i = chickens_used.find(ac);
+	if(i==chickens_used.end())
+	    throw konforka::exception(CODEPOINT,"you can't deallocate what is not allocated");
+	i->second--;
+	if(i->second>0)
+	    return;
+	chickens_used.erase(i);
+	chickens_free.push_front(ac);
+    }
+
+    /*
+     * so_component
+     */
+
+    so_component::so_component(component_so *h,sitecing_interface *scif)
+	: hen(h), ac(NULL) {
+	    if(!hen)
+		throw konforka::exception(CODEPOINT,"can't get an egg from the null-hen");
+	    ac = hen->allocate_chicken();
+	    ac->__set_interface(scif);
+	}
+
+    void so_component::attach(component_so *h,acomponent *a) {
+	detach(); hen = h; ac = a;
+	if(!ac)
+	    throw konforka::exception(CODEPOINT,"trying to clone null-chicken");
+	if(!hen)
+	    throw konforka::exception(CODEPOINT,"trying to clone orphan chicken");
+	hen->allocate_chicken(ac);
+    }
+    void so_component::detach() {
+	if(hen && ac)
+	    hen->deallocate_chicken(ac);
+    }
+
+}
--
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