Strawman implementation of post, put and delete on a tinycdb database, for now just a simplistic rewrite of the db per update.

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@935274 13f79535-47bb-0310-9956-ffa450edef68

8 files changed, 725 insertions, 0 deletions

diff --git a/sca-cpp/trunk/components/nosqldb/Makefile.am b/sca-cpp/trunk/components/nosqldb/Makefile.am
new file mode 100644
index 0000000000..6a9b0bdfdd
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/Makefile.am
@@ -0,0 +1,42 @@
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#  
+#    http://www.apache.org/licenses/LICENSE-2.0
+#    
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+
+if WANT_NOSQLDB
+
+INCLUDES = -I${TINYCDB_INCLUDE}
+
+compdir=$(prefix)/components/nosqldb
+
+comp_DATA = tinycdb.prefix
+tinycdb.prefix: $(top_builddir)/config.status
+	echo ${TINYCDB_PREFIX} >tinycdb.prefix
+
+#comp_LTLIBRARIES = libnosqldb.la
+
+#libnosqldb_la_SOURCES = nosqldb.cpp
+#libnosqldb_la_LDFLAGS = -L${TINYCDB_LIB} -R${TINYCDB_LIB} -lcdb
+
+tinycdb_test_SOURCES = tinycdb-test.cpp
+tinycdb_test_LDFLAGS = -L${TINYCDB_LIB} -R${TINYCDB_LIB} -lcdb
+
+client_test_SOURCES = client-test.cpp
+client_test_LDFLAGS = -lxml2 -lcurl -lmozjs
+
+noinst_PROGRAMS = tinycdb-test client-test
+TESTS = nosqldb-test 
+
+endif
diff --git a/sca-cpp/trunk/components/nosqldb/client-test.cpp b/sca-cpp/trunk/components/nosqldb/client-test.cpp
new file mode 100644
index 0000000000..4d3cc1ec29
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/client-test.cpp
@@ -0,0 +1,130 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/* $Rev$ $Date$ */
+
+/**
+ * Test NoSQL database component.
+ */
+
+#include <assert.h>
+#include "stream.hpp"
+#include "string.hpp"
+
+#include "list.hpp"
+#include "value.hpp"
+#include "monad.hpp"
+#include "perf.hpp"
+#include "../../modules/http/curl.hpp"
+
+namespace tuscany {
+namespace nosqldb {
+
+const string uri("http://localhost:8090/nosqldb");
+
+bool testNoSqlDb() {
+    http::CURLSession cs;
+
+    const list<value> i = list<value>()
+            + (list<value>() + "name" + string("Apple"))
+            + (list<value>() + "price" + string("$2.99"));
+    const list<value> a = mklist<value>(string("item"), string("cart-53d67a61-aa5e-4e5e-8401-39edeba8b83b"), i);
+
+    const failable<value> id = http::post(a, uri, cs);
+    assert(hasContent(id));
+
+    const string p = path(content(id));
+    {
+        const failable<value> val = http::get(uri + p, cs);
+        assert(hasContent(val));
+        assert(content(val) == a);
+    }
+
+    const list<value> j = list<value>()
+            + (list<value>() + "name" + string("Apple"))
+            + (list<value>() + "price" + string("$3.55"));
+    const list<value> b = mklist<value>(string("item"), string("cart-53d67a61-aa5e-4e5e-8401-39edeba8b83b"), j);
+
+    {
+        const failable<value> r = http::put(b, uri + p, cs);
+        assert(hasContent(r));
+        assert(content(r) == value(true));
+    }
+    {
+        const failable<value> val = http::get(uri + p, cs);
+        assert(hasContent(val));
+        assert(content(val) == b);
+    }
+    {
+        const failable<value> r = http::del(uri + p, cs);
+        assert(hasContent(r));
+        assert(content(r) == value(true));
+    }
+    {
+        const failable<value> val = http::get(uri + p, cs);
+        assert(!hasContent(val));
+    }
+
+    return true;
+}
+
+struct getLoop {
+    const string path;
+    const value entry;
+    http::CURLSession cs;
+    getLoop(const string& path, const value& entry, http::CURLSession cs) : path(path), entry(entry), cs(cs) {
+    }
+    const bool operator()() const {
+        const failable<value> val = http::get(uri + path, cs);
+        assert(hasContent(val));
+        assert(content(val) == entry);
+        return true;
+    }
+};
+
+bool testGetPerf() {
+    const list<value> i = list<value>()
+            + (list<value>() + "name" + string("Apple"))
+            + (list<value>() + "price" + string("$4.55"));
+    const value a = mklist<value>(string("item"), string("cart-53d67a61-aa5e-4e5e-8401-39edeba8b83b"), i);
+
+    http::CURLSession cs;
+    const failable<value> id = http::post(a, uri, cs);
+    assert(hasContent(id));
+    const string p = path(content(id));
+
+    const lambda<bool()> gl = getLoop(p, a, cs);
+    cout << "NoSqldb get test " << time(gl, 5, 200) << " ms" << endl;
+
+    return true;
+}
+
+}
+}
+
+int main() {
+    tuscany::cout << "Testing..." << tuscany::endl;
+
+    tuscany::nosqldb::testNoSqlDb();
+    tuscany::nosqldb::testGetPerf();
+
+    tuscany::cout << "OK" << tuscany::endl;
+
+    return 0;
+}
diff --git a/sca-cpp/trunk/components/nosqldb/nosqldb-test b/sca-cpp/trunk/components/nosqldb/nosqldb-test
new file mode 100755
index 0000000000..d1f9746860
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/nosqldb-test
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#  
+#    http://www.apache.org/licenses/LICENSE-2.0
+#    
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+
+# Setup
+mkdir -p tmp
+rm -f tmp/db.cdb
+cat >tmp/db.txt <<EOF
+EOF
+./tinycdb -c -m tmp/db.cdb <tmp/db.txt
+
+# Test
+./tinycdb-test # 2>/dev/null
+rc=$?
+
+# Cleanup
+return $rc
diff --git a/sca-cpp/trunk/components/nosqldb/server-test b/sca-cpp/trunk/components/nosqldb/server-test
new file mode 100755
index 0000000000..784c7156c5
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/server-test
@@ -0,0 +1,43 @@
+#!/bin/sh
+
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#  
+#    http://www.apache.org/licenses/LICENSE-2.0
+#    
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+
+# Setup
+../../modules/http/httpd-conf tmp localhost 8090 ../../modules/http/htdocs
+../../modules/server/server-conf tmp
+../../modules/server/scheme-conf tmp
+cat >>tmp/conf/httpd.conf <<EOF
+SCAContribution `pwd`/
+SCAComposite sqldb.composite
+EOF
+
+./pgsql-start tmp
+./pgsql "drop table test;" 1>/dev/null 2>&1
+./pgsql "create table test(key text, value text);" 1>/dev/null 2>&1
+../../modules/http/httpd-start tmp
+sleep 2
+
+# Test
+./client-test 2>/dev/null
+rc=$?
+
+# Cleanup
+../../modules/http/httpd-stop tmp
+./pgsql-stop tmp
+sleep 2
+return $rc
diff --git a/sca-cpp/trunk/components/nosqldb/store.composite b/sca-cpp/trunk/components/nosqldb/store.composite
new file mode 100644
index 0000000000..ccfd61fc4d
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/store.composite
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * 
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.    
+-->
+<composite xmlns="http://docs.oasis-open.org/ns/opencsa/sca/200912"
+  xmlns:t="http://tuscany.apache.org/xmlns/sca/1.1"
+  targetNamespace="http://tuscany.apache.org/xmlns/sca/components"
+  name="store">
+        
+    <component name="store">
+        <implementation.cpp path=".libs" library="libstore"/>
+        <service name="store">
+            <t:binding.http uri="store"/>
+        </service>
+    </component>     
+
+</composite>
diff --git a/sca-cpp/trunk/components/nosqldb/tinycdb b/sca-cpp/trunk/components/nosqldb/tinycdb
new file mode 100755
index 0000000000..68459d7622
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/tinycdb
@@ -0,0 +1,24 @@
+#!/bin/sh
+
+#  Licensed to the Apache Software Foundation (ASF) under one
+#  or more contributor license agreements.  See the NOTICE file
+#  distributed with this work for additional information
+#  regarding copyright ownership.  The ASF licenses this file
+#  to you under the Apache License, Version 2.0 (the
+#  "License"); you may not use this file except in compliance
+#  with the License.  You may obtain a copy of the License at
+#  
+#    http://www.apache.org/licenses/LICENSE-2.0
+#    
+#  Unless required by applicable law or agreed to in writing,
+#  software distributed under the License is distributed on an
+#  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+#  KIND, either express or implied.  See the License for the
+#  specific language governing permissions and limitations
+#  under the License.
+
+here=`readlink -f $0`; here=`dirname $here`
+tinycdb_prefix=`cat $here/tinycdb.prefix`
+
+$tinycdb_prefix/bin/cdb $*
+
diff --git a/sca-cpp/trunk/components/nosqldb/tinycdb-test.cpp b/sca-cpp/trunk/components/nosqldb/tinycdb-test.cpp
new file mode 100644
index 0000000000..4eeb92d3fc
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/tinycdb-test.cpp
@@ -0,0 +1,82 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/* $Rev$ $Date$ */
+
+/**
+ * Test TinyCDB access functions.
+ */
+
+#include <assert.h>
+#include "stream.hpp"
+#include "string.hpp"
+#include "perf.hpp"
+#include "tinycdb.hpp"
+
+namespace tuscany {
+namespace tinycdb {
+
+bool testTinyCDB() {
+    TinyCDB cdb("tmp/db.cdb");
+    const value k = mklist<value>("a");
+
+    assert(hasContent(post(k, string("AAA"), cdb)));
+    assert((get(k, cdb)) == value(string("AAA")));
+    assert(hasContent(put(k, string("aaa"), cdb)));
+    assert((get(k, cdb)) == value(string("aaa")));
+    assert(hasContent(del(k, cdb)));
+    assert(!hasContent(get(k, cdb)));
+
+    return true;
+}
+
+struct getLoop {
+    const value k;
+    TinyCDB& cdb;
+    getLoop(const value& k, TinyCDB& cdb) : k(k), cdb(cdb) {
+    }
+    const bool operator()() const {
+        assert((get(k, cdb)) == value(string("CCC")));
+        return true;
+    }
+};
+
+bool testGetPerf() {
+    const value k = mklist<value>("c");
+    TinyCDB cdb("tmp/db.cdb");
+    assert(hasContent(post(k, string("CCC"), cdb)));
+
+    const lambda<bool()> gl = getLoop(k, cdb);
+    cout << "TinyCDB get test " << time(gl, 5, 100000) << " ms" << endl;
+    return true;
+}
+
+}
+}
+
+int main() {
+    tuscany::cout << "Testing..." << tuscany::endl;
+
+    tuscany::tinycdb::testTinyCDB();
+    tuscany::tinycdb::testGetPerf();
+
+    tuscany::cout << "OK" << tuscany::endl;
+
+    return 0;
+}
diff --git a/sca-cpp/trunk/components/nosqldb/tinycdb.hpp b/sca-cpp/trunk/components/nosqldb/tinycdb.hpp
new file mode 100644
index 0000000000..c2d1f2c50f
--- /dev/null
+++ b/sca-cpp/trunk/components/nosqldb/tinycdb.hpp
@@ -0,0 +1,340 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/* $Rev$ $Date$ */
+
+#ifndef tuscany_tinycdb_hpp
+#define tuscany_tinycdb_hpp
+
+#include <fcntl.h>
+#include <cdb.h>
+
+#include "string.hpp"
+#include "list.hpp"
+#include "value.hpp"
+#include "monad.hpp"
+#include "../../modules/scheme/eval.hpp"
+
+namespace tuscany {
+namespace tinycdb {
+
+/**
+ * A reallocatable buffer.
+ */
+class buffer {
+public:
+    operator void*() const throw() {
+        return buf;
+    }
+
+    operator unsigned char*() const throw() {
+        return (unsigned char*)buf;
+    }
+
+    operator char*() const throw() {
+        return (char*)buf;
+    }
+
+private:
+    buffer(const unsigned int size, void* buf) : size(size), buf(buf) {
+    }
+
+    unsigned int size;
+    void* buf;
+
+    friend const buffer mkbuffer(const unsigned int sz);
+    friend const buffer mkbuffer(const buffer& b, const unsigned int newsz);
+    friend const bool free(const buffer& b);
+};
+
+/**
+ * Make a new buffer.
+ */
+const buffer mkbuffer(const unsigned int sz) {
+    return buffer(sz, malloc(sz));
+}
+
+/**
+ * Make a new buffer by reallocating an existing one.
+ */
+const buffer mkbuffer(const buffer& b, const unsigned int sz) {
+    if (sz <= b.size)
+        return b;
+    return buffer(sz, realloc(b.buf, sz));
+}
+
+/**
+ * Free a buffer.
+ */
+const bool free(const buffer&b) {
+    ::free(b.buf);
+    return true;
+}
+
+/**
+ * Represents a TinyCDB connection.
+ */
+class TinyCDB {
+public:
+    TinyCDB() : owner(false) {
+    }
+
+    TinyCDB(const string& file) : owner(true), file(file) {
+        fd = open(c_str(file), O_RDONLY);
+    }
+
+    TinyCDB(const TinyCDB& c) : owner(false) {
+        file = c.file;
+        fd = c.fd;
+    }
+
+    ~TinyCDB() {
+        if (!owner)
+            return;
+        if (fd == -1)
+            return;
+        close(fd);
+    }
+
+private:
+    bool owner;
+    string file;
+    int fd;
+
+    friend const failable<bool> post(const value& key, const value& val, TinyCDB& cdb);
+    friend const failable<bool> put(const value& key, const value& val, const TinyCDB& cdb);
+    friend const failable<value> get(const value& key, const TinyCDB& cdb);
+    friend const failable<bool> del(const value& key, const TinyCDB& cdb);
+    friend const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, TinyCDB& cdb);
+    friend const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, buffer& buf, const int fd, TinyCDB& cdb);
+};
+
+/**
+ * Rewrite a database. The given update function is passed each entry, and
+ * can return true to let the entry added to the new db, false to skip the
+ * entry, or a failure.
+ */
+const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, buffer& buf, const int fd, TinyCDB& cdb) {
+
+    // Initialize new db structure
+    struct cdb_make cdbm;
+    cdb_make_start(&cdbm, fd);
+
+    // Read the db header
+    unsigned int pos = 0;
+    if (lseek(cdb.fd, 0, SEEK_SET) != 0)
+        return mkfailure<bool>("Could not seek to database start");
+    if (::read(cdb.fd, buf, 2048) != 2048)
+        return mkfailure<bool>("Could not read database header");
+    pos += 2048;
+    unsigned int eod = cdb_unpack(buf);
+    debug(pos, "tinycdb::post::eod");
+
+    // Read and add the existing entries
+    while(pos < eod) {
+        if (eod - pos < 8)
+            return mkfailure<bool>("Invalid database format, couldn't read entry header");
+        if (::read(cdb.fd, buf, 8) != 8)
+            return mkfailure<bool>("Couldn't read entry header");
+        pos += 8;
+        unsigned int klen = cdb_unpack(buf);
+        unsigned int vlen = cdb_unpack(((unsigned char*)buf) + 4);
+        unsigned int elen = klen + vlen;
+
+        // Read existing entry
+        buf = mkbuffer(buf, elen);
+        if (eod - pos < elen)
+            return mkfailure<bool>("Invalid database format, couldn't read entry");
+        if ((unsigned int)::read(cdb.fd, buf, elen) != elen)
+            return mkfailure<bool>("Couldn't read entry");
+        pos += elen;
+
+        // Apply the update function to the entry
+        debug(string((char*)buf, klen), "tinycdb::post::existing key");
+        debug(string(((char*)buf) + klen, vlen), "tinycdb::post::existing value");
+        const failable<bool> u = update(buf, klen, vlen);
+        if (!hasContent(u))
+            return u;
+
+        // Skip the entry if the update function returned false
+        if (u == false)
+            continue;
+
+        // Add the entry to the new db
+        if (cdb_make_add(&cdbm, buf, klen, ((unsigned char*)buf)+klen, vlen) == -1)
+            return mkfailure<bool>("Could not add entry");
+    }
+    if (pos != eod)
+        return mkfailure<bool>("Invalid database format");
+
+    // Call the finish function
+    const failable<bool> f = finish(cdbm);
+    if (!hasContent(f))
+        return f;
+
+    // Save the new db
+    if (cdb_make_finish(&cdbm) == -1)
+        return mkfailure<bool>("Could not save database");
+
+    return true;
+}
+
+const failable<bool> rewrite(const lambda<failable<bool>(buffer& buf, const unsigned int klen, const unsigned int vlen)>& update, const lambda<failable<bool>(struct cdb_make&)>& finish, TinyCDB& cdb) {
+    if (cdb.fd == -1)
+        return mkfailure<bool>("Could not open database");
+
+    // Create a new temporary db file
+    const char* tmpfile = c_str(cdb.file + ".tmp");
+    unlink(tmpfile);
+    int fd = open(tmpfile, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW, 0666);
+    if (fd == -1)
+        return mkfailure<bool>("Could not create temporary database");
+
+    // Rewrite the db, apply the update function to each entry
+    buffer buf = mkbuffer(2048);
+    const failable<bool> r = rewrite(update, finish, buf, fd, cdb);
+    if (!hasContent(r)) {
+        close(fd);
+        free(buf);
+        return r;
+    }
+
+    // Atomically replace the db and reopen it in read mode
+    if (rename(tmpfile, c_str(cdb.file)) == -1)
+        return mkfailure<bool>("Could not rename temporary database");
+    close(cdb.fd);
+    cdb.fd = open(c_str(cdb.file), O_RDONLY);
+
+    return true;
+}
+
+/**
+ * Post a new item to the database.
+ */
+const failable<bool> post(const value& key, const value& val, TinyCDB& cdb) {
+    debug(key, "tinycdb::post::key");
+    debug(val, "tinycdb::post::value");
+
+    const string ks(scheme::writeValue(key));
+    const string vs(scheme::writeValue(val));
+
+    // Process each entry and detect existing key
+    auto update = [=](buffer& buf, const unsigned int klen, unused const unsigned int vlen)->const failable<bool> {
+        if (ks == string((char*)buf, klen))
+            return mkfailure<bool>("Key already exists");
+        return true;
+    };
+
+    // Add the new entry to the db
+    auto finish = [=](struct cdb_make& cdbm)->const failable<bool> {
+        if (cdb_make_add(&cdbm, c_str(ks), length(ks), c_str(vs), length(vs)) == -1)
+            return mkfailure<bool>("Could not add entry");
+        return true;
+    };
+
+    // Rewrite the db
+    const failable<bool> r = rewrite(update, finish, cdb);
+    debug(r, "tinycdb::post::result");
+    return r;
+}
+
+/**
+ * Update an item in the database. If the item doesn't exist it is added.
+ */
+const failable<bool> put(const value& key, const value& val, TinyCDB& cdb) {
+    debug(key, "tinycdb::put::key");
+    debug(val, "tinycdb::put::value");
+
+    const string ks(scheme::writeValue(key));
+    const string vs(scheme::writeValue(val));
+
+    // Process each entry and skip existing key
+    auto update = [&](buffer& buf, const unsigned int klen, unused const unsigned int vlen)->const failable<bool> {
+        if (ks == string((char*)buf, klen))
+            return false;
+        return true;
+    };
+
+    // Add the new entry to the db
+    auto finish = [&](struct cdb_make& cdbm)->const failable<bool> {
+        if (cdb_make_add(&cdbm, c_str(ks), length(ks), c_str(vs), length(vs)) == -1)
+            return mkfailure<bool>("Could not add entry");
+        return true;
+    };
+
+    // Rewrite the db
+    const failable<bool> r = rewrite(update, finish, cdb);
+    debug(r, "tinycdb::put::result");
+    return r;
+}
+
+/**
+ * Get an item from the database.
+ */
+const failable<value> get(const value& key, const TinyCDB& cdb) {
+    debug(key, "tinycdb::get::key");
+    if (cdb.fd == -1)
+        return mkfailure<value>("Could not open database");
+
+    const string ks(scheme::writeValue(key));
+
+    cdbi_t vlen;
+    if (cdb_seek(cdb.fd, c_str(ks), length(ks), &vlen) <= 0)
+        return mkfailure<value>("Could not get entry");
+    char* data = gc_cnew(vlen + 1);
+    cdb_bread(cdb.fd, data, vlen);
+    data[vlen] = '\0';
+    const value val(scheme::readValue(string(data)));
+
+    debug(val, "tinycdb::get::result");
+    return val;
+}
+
+/**
+ * Delete an item from the database
+ */
+const failable<bool> del(const value& key, TinyCDB& cdb) {
+    debug(key, "tinycdb::delete::key");
+
+    const string ks(scheme::writeValue(key));
+
+    // Process each entry and skip existing key
+    auto update = [=](buffer& buf, const unsigned int klen, unused const unsigned int vlen)->const failable<bool> {
+        if (ks == string((char*)buf, klen))
+            return false;
+        return true;
+    };
+
+    // Nothing to do to finish
+    auto finish = [=](unused struct cdb_make& cdbm)->const failable<bool> {
+        // hack: reference a variable from outer scope to workaround GCC internal error
+        const string xs(ks);
+        return true;
+    };
+
+    // Rewrite the db
+    const failable<bool> r = rewrite(update, finish, cdb);
+    debug(r, "tinycdb::delete::result");
+    return r;
+}
+
+}
+}
+
+#endif /* tuscany_tinycdb_hpp */