Added 'k, m, g' suffix processing to Config class

Started writing the Cache class.  Mostly stubs right now.

CMakeLists.txt

@@ -24,6 +24,7 @@ set(storagemanager_SRCS
     src/CloudStorage.cpp
     src/S3Storage.cpp
     src/LocalStorage.cpp
+    src/Cache.cpp
 )
 
 option(TRACE "Enable some tracing output" OFF)

src/Cache.cpp

@@ -0,0 +1,79 @@
+
+#include "Cache.h"
+#include "Config.h"
+#include <iostream>
+#include <syslog.h>
+#include <boost/filesystem.hpp>
+
+using namespace std;
+using namespace boost::filesystem;
+
+namespace storagemanager
+{
+
+Cache::Cache()
+{
+    Config *conf = Config::get();
+
+    string ssize = conf->getValue("Cache", "cache_size");
+    if (ssize.empty()) 
+    {
+        syslog(LOG_CRIT, "Cache/cache_size is not set");
+        throw runtime_error("Please set Cache/cache_size in the storagemanager.cnf file");
+    }
+    try
+    {
+        maxCacheSize = stol(ssize);
+    }
+    catch (invalid_argument &)
+    {
+        syslog(LOG_CRIT, "Cache/cache_size is not a number");
+        throw runtime_error("Please set Cache/cache_size to a number");
+    }
+        
+    prefix = conf->getValue("Cache", "path");
+    if (prefix.empty())
+    {
+        syslog(LOG_CRIT, "Cache/path is not set");
+        throw runtime_error("Please set Cache/path in the storagemanager.cnf file");
+    }
+    try 
+    {
+        boost::filesystem::create_directories(prefix);
+    }
+    catch (exception &e)
+    {
+        syslog(LOG_CRIT, "Failed to create %s, got: %s", prefix.string().c_str(), e.what());
+        throw e;
+    }
+}
+
+Cache::~Cache()
+{
+}
+
+void Cache::read(const vector<string> &keys)
+{
+}
+
+void Cache::exists(const vector<string> &keys, vector<bool> *out)
+{
+}
+
+void Cache::newObject(const string &key, size_t size)
+{
+}
+
+void Cache::deletedObject(const string &key, size_t size)
+{
+}
+
+void Cache::setCacheSize(size_t size)
+{
+}
+
+void Cache::makeSpace(size_t size)
+{
+}
+
+}

src/Cache.h

@@ -0,0 +1,34 @@
+
+#ifndef CACHE_H_
+#define CACHE_H_
+
+#include <string>
+#include <vector>
+#include <boost/utility.hpp>
+#include <boost/filesystem/path.hpp>
+
+namespace storagemanager
+{
+
+class Cache : public boost::noncopyable
+{
+    public:
+        Cache();
+        virtual ~Cache();
+        
+        void read(const std::vector<std::string> &keys);
+        void exists(const std::vector<std::string> &keys, std::vector<bool> *out);
+        void newObject(const std::string &key, size_t size);
+        void deletedObject(const std::string &key, size_t size);
+        void setCacheSize(size_t size);
+        void makeSpace(size_t size);
+
+    private:
+        boost::filesystem::path prefix;
+        size_t maxCacheSize;
+        
+};
+
+}
+
+#endif

src/Config.cpp

@@ -63,12 +63,26 @@ Config::Config()
     boost::property_tree::ini_parser::read_ini(filename, contents);
 }
 
-string use_envvar(boost::smatch envvar)
+string use_envvar(const boost::smatch &envvar)
 {
     char *env = getenv(envvar[1].str().c_str());
     return (env ? env : "");
 }
 
+string expand_numbers(const boost::smatch &match)
+{
+    long num = stol(match[1].str());
+    char suffix = (char) ::tolower(match[2].str()[0]);
+
+    if (suffix == 'g')
+        num <<= 30;
+    else if (suffix == 'm')
+        num <<= 20;
+    else if (suffix == 'k')
+        num <<= 10;
+    return ::to_string(num);
+}
+    
 string Config::getValue(const string &section, const string &key) const
 {
     // if we care, move this envvar substition stuff to where the file is loaded
@@ -76,6 +90,13 @@ string Config::getValue(const string &section, const string &key) const
     boost::regex re("\\$\\{(.+)\\}");
     
     ret = boost::regex_replace(ret, re, use_envvar);
+    
+    // do the numeric substitutions.  ex, the suffixes m, k, g
+    // ehhhhh.  going to end up turning a string to a number, to a string, and then to a number again
+    // don't like that.  OTOH who cares.
+    boost::regex num_re("^([[:digit:]]+)([mMkKgG])$", boost::regex::extended);
+    ret = boost::regex_replace(ret, num_re, expand_numbers);
+    
     return ret;
 }
 

storagemanager.cnf

@@ -12,5 +12,9 @@ region = us-west-1
 # see https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-configure.html
 
 [LocalStorage]
-path = ${HOME}/fake-cloud/
+path = ${HOME}/fake-cloud
+
+[Cache]
+cache_size = 2g
+path = ${HOME}/cache