Runtime configuration system for skia. This will allow developers to control settings at launch time without relying on compile-time flags or recompilation. It can be used to turn features on and off, as well as to control numeric quantities to 'tune' algorithms. Once I make sure it's working across all platforms I'll send out a quick tutorial on its use.

Review URL: https://codereview.appspot.com/7098051

git-svn-id: http://skia.googlecode.com/svn/trunk@7158 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 325 insertions, 0 deletions

diff --git a/src/utils/SkRTConf.cpp b/src/utils/SkRTConf.cpp
new file mode 100644
index 0000000000..fcc51c33c3
--- /dev/null
+++ b/src/utils/SkRTConf.cpp
@@ -0,0 +1,325 @@
+/*
+ * 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++) {
+        
+        SkRTConf<bool> *concrete = dynamic_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;
+}