src/utils/SkRTConf.cpp

/*
 * Copyright 2013 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkRTConf.h"
#include "SkOSFile.h"

SkRTConfRegistry::SkRTConfRegistry(): fConfs(100) {
    
    SkFILE *fp = sk_fopen(configFileLocation(), kRead_SkFILE_Flag);

    if (!fp) {
        return;
    }
    
    char *line = NULL;
    size_t n = 0;
    
    while (!sk_feof(fp)) {
        if (line) {
            sk_free(line);
        }
        line = NULL;
        
        if (sk_getline(&line, &n, fp) == -1) break;
                
        char *commentptr = strchr(line, '#');
        if (commentptr == line) {
            continue;
        }
        if (NULL != commentptr) {
            char *tmp = (char *) sk_malloc_throw(commentptr-line+1);
            strncpy(tmp, line, commentptr-line);
            sk_free(line);
            line = tmp;
        }
        
        char sep[] = " \t";
        
        char *keyptr = strtok(line, sep);
        if (!keyptr) {
            continue;
        }

        char *valptr = strtok(NULL, sep);
        if (!valptr) {
            continue;
        }
                
        SkString* key = new SkString(keyptr);
        SkString* val = new SkString(valptr);

        fConfigFileKeys.append(1, &key);
        fConfigFileValues.append(1, &val);
    }
    sk_fclose(fp);
}

const char *SkRTConfRegistry::configFileLocation() const {
    return "skia.conf"; // for now -- should probably do something fancier like home directories or whatever.
}

// dump all known runtime config options to the file with their default values.
// to trigger this, make a config file of zero size.
void SkRTConfRegistry::possiblyDumpFile() const {
    const char *path = configFileLocation();
    SkFILE *fp = sk_fopen(path, kRead_SkFILE_Flag);
    if (!fp) {
        return;
    }
    size_t configFileSize = sk_fgetsize(fp);
    if (configFileSize == 0) {
        printAll(path);
    }
    sk_fclose(fp);
}

// Run through every provided configuration option and print a warning if the user hasn't
// declared a correponding configuration object somewhere.
void SkRTConfRegistry::validate() const {
    for (int i = 0 ; i < fConfigFileKeys.count() ; i++) {
        if (fConfs.find(fConfigFileKeys[i]->c_str()) == -1) {
            SkDebugf("WARNING: You have config value %s in your configuration file, but I've never heard of that.\n", fConfigFileKeys[i]->c_str());
        }
    }
}

void SkRTConfRegistry::printAll(const char *fname) const {
    SkWStream *o;
    
    if (NULL != fname) {
        o = new SkFILEWStream(fname);
    } else {
        o = new SkDebugWStream();
    }
    
    ConfMap::Iter iter(fConfs);
    SkTDArray<SkRTConfBase *> *confArray;
    
    while (iter.next(&confArray)) {
        if (confArray->getAt(0)->isDefault()) {
            o->writeText("# ");
        }
        confArray->getAt(0)->print(o);
        o->newline();
    }
    
    delete o;
}

void SkRTConfRegistry::printNonDefault(const char *fname) const {
    SkWStream *o;
    
    if (NULL != fname) {
        o = new SkFILEWStream(fname);
    } else {
        o = new SkDebugWStream();
    }    
    ConfMap::Iter iter(fConfs);
    SkTDArray<SkRTConfBase *> *confArray;
    
    while (iter.next(&confArray)) {
        if (!confArray->getAt(0)->isDefault()) {
            confArray->getAt(0)->print(o);
            o->newline();
        }
    }
    
    delete o;
}

// register a configuration variable after its value has been set by the parser.
// we maintain a vector of these things instead of just a single one because the
// user might set the value after initialization time and we need to have
// all the pointers lying around, not just one.
void SkRTConfRegistry::registerConf(SkRTConfBase *conf) {
    SkTDArray<SkRTConfBase *> *confArray;
    if (fConfs.find(conf->getName(), &confArray)) {
        if (!conf->equals(confArray->getAt(0))) {
            SkDebugf("WARNING: Skia config \"%s\" was registered more than once in incompatible ways.\n", conf->getName());
        } else {
            confArray->append(1, &conf);
        }
    } else {
        confArray = new SkTDArray<SkRTConfBase *>;
        confArray->append(1, &conf);
        fConfs.set(conf->getName(),confArray);
    }
}

template <typename T> T doParse(const char *s, bool *success ) {
    SkDebugf("WARNING: Invoked non-specialized doParse function...\n");
    if (success) {
        *success = false;
    } 
    return (T) 0;
}

template<> bool doParse<bool>(const char *s, bool *success) {
    if (success) {
        *success = true;
    }
    if (!strcmp(s,"1") || !strcmp(s,"true")) {
        return true;
    }
    if (!strcmp(s,"0") || !strcmp(s,"false")) {
        return false;
    }
    if (success) {
        *success = false;
    }
    return false;
}

template<> const char * doParse<const char *>(const char * s, bool *success) {
    if (success) {
        *success = true;
    }
    return s;
}

template<> int doParse<int>(const char * s, bool *success) {
    return atoi(s);
}

template<> unsigned int doParse<unsigned int>(const char * s, bool *success) {
    return (unsigned int) atoi(s);
}

template<> float doParse<float>(const char * s, bool *success) {
    return (float) atof(s);
}

template<> double doParse<double>(const char * s, bool *success) {
    return atof(s);
}

static inline void str_replace(char *s, char search, char replace) {
    for (char *ptr = s ; *ptr ; ptr++) {
        if (*ptr == search) {
            *ptr = replace;
        }
    }
}

template<typename T> bool SkRTConfRegistry::parse(const char *name, T* value) {
    SkString *str = NULL;

    for (int i = 0 ; i < fConfigFileKeys.count() ; i++) {
        if (fConfigFileKeys[i]->equals(name)) {
            str = fConfigFileValues[i];
        }
    }
    
    SkString environment_variable("skia.");
    environment_variable.append(name);
    
    const char *environment_value = getenv(environment_variable.c_str());
    if (environment_value) {
        str->set(environment_value);
    } else {
        // apparently my shell doesn't let me have environment variables that 
        // have periods in them, so also let the user substitute underscores.
        SkString underscore_environment_variable("skia_");
        char *underscore_name = SkStrDup(name);
        str_replace(underscore_name,'.','_');
        underscore_environment_variable.append(underscore_name);
        sk_free(underscore_name);
        environment_value = getenv(underscore_environment_variable.c_str());
        if (environment_value) {
            str->set(environment_value);
        }
    }
    
    if (!str) {
        return false;
    }
    
    bool success;
    T new_value = doParse<T>(str->c_str(),&success);
    if (success) {
        *value = new_value;
    } else {
        SkDebugf("WARNING: Couldn't parse value \'%s\' for variable \'%s\'\n", str->c_str(), name);
    }
    return success;
}

// need to explicitly instantiate the parsing function for every config type we might have...

template bool SkRTConfRegistry::parse(const char *name, bool *value);
template bool SkRTConfRegistry::parse(const char *name, int *value);
template bool SkRTConfRegistry::parse(const char *name, unsigned int *value);
template bool SkRTConfRegistry::parse(const char *name, float *value);
template bool SkRTConfRegistry::parse(const char *name, double *value);
template bool SkRTConfRegistry::parse(const char *name, const char **value);

template <typename T> void SkRTConfRegistry::set(const char *name, T value) {
    
    SkTDArray<SkRTConfBase *> *confArray;
    if (!fConfs.find(name, &confArray)) {
        SkDebugf("WARNING: Attempting to set configuration value \"%s\", but I've never heard of that.\n", name);
        return;
    }
    
    for (SkRTConfBase **confBase = confArray->begin(); confBase != confArray->end(); confBase++) {
        // static_cast here is okay because there's only one kind of child class.
        SkRTConf<bool> *concrete = static_cast<SkRTConf<bool> *>(*confBase);
        
        if (concrete) {
            concrete->set(value);
        }
    }
}

template void SkRTConfRegistry::set(const char *name, bool value);
template void SkRTConfRegistry::set(const char *name, int value);
template void SkRTConfRegistry::set(const char *name, unsigned int value);
template void SkRTConfRegistry::set(const char *name, float value);
template void SkRTConfRegistry::set(const char *name, double value);
template void SkRTConfRegistry::set(const char *name, char * value);

template<> void SkRTConf<bool>::doPrint(char *s) const {
    char tmp[30];
    sprintf(tmp, "%s # [%s]", fValue ? "true" : "false", fDefault ? "true" : "false");
    sprintf(s, "%-30.30s", tmp);
}

template<> void SkRTConf<int>::doPrint(char *s) const {
    char tmp[30];
    sprintf(tmp, "%d # [%d]", fValue, fDefault);
    sprintf(s, "%-30.30s", tmp);
}

template<> void SkRTConf<unsigned int>::doPrint(char *s) const {
    char tmp[30];
    sprintf(tmp, "%u # [%u]", fValue, fDefault);
    sprintf(s, "%-30.30s", tmp);
}

template<> void SkRTConf<float>::doPrint(char *s) const {
    char tmp[30];
    sprintf(tmp, "%6.6f # [%6.6f]", fValue, fDefault);
    sprintf(s, "%-30.30s", tmp);
}

template<> void SkRTConf<double>::doPrint(char *s) const {
    char tmp[30];
    sprintf(tmp, "%6.6f # [%6.6f]", fValue, fDefault);
    sprintf(s, "%-30.30s", tmp);
}

template<> void SkRTConf<const char *>::doPrint(char *s) const {
    char tmp[30];
    sprintf(tmp, "%s # [%s]", fValue, fDefault);
    sprintf(s, "%-30.30s", tmp);
}

SkRTConfRegistry &skRTConfRegistry() {
    static SkRTConfRegistry r;
    return r;
}