[codegen][Python] Add model cache to speed up code generation (#7220)

* Add modelName to schema cache.

* Add modelName to schema cache.

* add cache optimizations

* add cache optimizations

* remove unused variable

modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

@@ -246,6 +246,9 @@ public class DefaultCodegen implements CodegenConfig {
     // make openapi available to all methods
     protected OpenAPI openAPI;
 
+    // A cache to efficiently lookup a Schema instance based on the return value of `toModelName()`.
+    private Map<String, Schema> modelNameToSchemaCache;
+
     public List<CliOption> cliOptions() {
         return cliOptions;
     }
@@ -449,6 +452,23 @@ public class DefaultCodegen implements CodegenConfig {
         return objs;
     }
 
+    /**
+     * Return a map from model name to Schema for efficient lookup.
+     * 
+     * @return map from model name to Schema.
+     */
+    protected Map<String, Schema> getModelNameToSchemaCache() {
+        if (modelNameToSchemaCache == null) {
+            // Create a cache to efficiently lookup schema based on model name.
+            Map<String, Schema> m = new HashMap<String, Schema>();
+            ModelUtils.getSchemas(openAPI).forEach((key, schema) -> {
+                m.put(toModelName(key), schema);
+            });
+            modelNameToSchemaCache = Collections.unmodifiableMap(m);
+        }
+        return modelNameToSchemaCache;
+    }
+
     /**
      * Index all CodegenModels by model name.
      *
@@ -1292,14 +1312,13 @@ public class DefaultCodegen implements CodegenConfig {
      * @param name the variable name
      * @return the sanitized variable name
      */
-    public String toVarName(String name) {
+    public String toVarName(final String name) {
         if (reservedWords.contains(name)) {
             return escapeReservedWord(name);
         } else if (((CharSequence) name).chars().anyMatch(character -> specialCharReplacements.keySet().contains("" + ((char) character)))) {
             return escape(name, specialCharReplacements, null, null);
-        } else {
-            return name;
         }
+        return name;
     }
 
     /**
@@ -1309,14 +1328,15 @@ public class DefaultCodegen implements CodegenConfig {
      * @param name Codegen property object
      * @return the sanitized parameter name
      */
-    public String toParamName(String name) {
-        name = removeNonNameElementToCamelCase(name); // FIXME: a parameter should not be assigned. Also declare the methods parameters as 'final'.
-        if (reservedWords.contains(name)) {
-            return escapeReservedWord(name);
-        } else if (((CharSequence) name).chars().anyMatch(character -> specialCharReplacements.keySet().contains("" + ((char) character)))) {
-            return escape(name, specialCharReplacements, null, null);
+    public String toParamName(final String name) {
+        String modifiable = removeNonNameElementToCamelCase(name); // FIXME: a parameter should not be assigned. Also declare the methods parameters as 'final'.
+        if (reservedWords.contains(modifiable)) {
+            return escapeReservedWord(modifiable);
+        } else if (((CharSequence) modifiable).chars().anyMatch(character -> specialCharReplacements.keySet().contains("" + ((char) character)))) {
+            return escape(modifiable, specialCharReplacements, null, null);
         }
-        return name;
+        return modifiable;
+
     }
 
     /**
@@ -2178,7 +2198,8 @@ public class DefaultCodegen implements CodegenConfig {
     }
 
     /**
-     * Output the proper model name (capitalized).
+     * Converts the OpenAPI schema name to a model name suitable for the current code generator.
+     * May be overriden for each programming language.
      * In case the name belongs to the TypeSystem it won't be renamed.
      *
      * @param name the name of the model
@@ -2188,6 +2209,32 @@ public class DefaultCodegen implements CodegenConfig {
         return camelize(modelNamePrefix + "_" + name + "_" + modelNameSuffix);
     }
 
+    private static class NamedSchema {
+        private NamedSchema(String name, Schema s) {
+            this.name = name;
+            this.schema = s;
+        }
+        private String name;
+        private Schema schema;
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            NamedSchema that = (NamedSchema) o;
+            return Objects.equals(name, that.name) &&
+                    Objects.equals(schema, that.schema);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, schema);
+        }
+    }
+
+    Map<NamedSchema, CodegenModel> schemaCodegenModelCache = new HashMap<NamedSchema, CodegenModel>();
+    Map<NamedSchema, CodegenProperty> schemaCodegenPropertyCache = new HashMap<NamedSchema, CodegenProperty>();
+
     /**
      * Convert OAS Model object to Codegen Model object
      *
@@ -2196,6 +2243,13 @@ public class DefaultCodegen implements CodegenConfig {
      * @return Codegen Model object
      */
     public CodegenModel fromModel(String name, Schema schema) {
+        NamedSchema ns = new NamedSchema(name, schema);
+        CodegenModel cm = schemaCodegenModelCache.get(ns);
+        if (cm != null) {
+            LOGGER.debug("Cached fromModel for " + name + " : " + schema.getName());
+            return cm;
+        }
+
         Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
         if (typeAliases == null) {
             // Only do this once during first call
@@ -2544,7 +2598,7 @@ public class DefaultCodegen implements CodegenConfig {
                 postProcessModelProperty(m, prop);
             }
         }
-
+        schemaCodegenModelCache.put(ns, m);
         return m;
     }
 
@@ -2976,7 +3030,12 @@ public class DefaultCodegen implements CodegenConfig {
             return null;
         }
         LOGGER.debug("debugging fromProperty for " + name + " : " + p);
-
+        NamedSchema ns = new NamedSchema(name, p);
+        CodegenProperty c = schemaCodegenPropertyCache.get(ns);
+        if (c != null) {
+            LOGGER.debug("Cached fromProperty for " + name + " : " + p.getName());
+            return c;
+        }
         // unalias schema
         p = ModelUtils.unaliasSchema(this.openAPI, p, importMapping);
 
@@ -3278,6 +3337,7 @@ public class DefaultCodegen implements CodegenConfig {
         }
 
         LOGGER.debug("debugging from property return: " + property);
+        schemaCodegenPropertyCache.put(ns, property);
         return property;
     }
 
@@ -6356,6 +6416,9 @@ public class DefaultCodegen implements CodegenConfig {
                 .featureSet(builder.build()).build();
     }
 
+    /**
+     * An map entry for cached sanitized names.
+     */
     private static class SanitizeNameOptions {
         public SanitizeNameOptions(String name, String removeCharRegEx, List<String> exceptions) {
             this.name = name;
@@ -6363,7 +6426,7 @@ public class DefaultCodegen implements CodegenConfig {
             if (exceptions != null) {
                 this.exceptions = Collections.unmodifiableList(exceptions);
             } else {
-                this.exceptions = Collections.unmodifiableList(new ArrayList<>());
+                this.exceptions = Collections.emptyList();
             }
         }
 

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientExperimentalCodegen.java

@@ -447,19 +447,16 @@ public class PythonClientExperimentalCodegen extends PythonClientCodegen {
         }
 
         String varDataType = var.mostInnerItems != null ? var.mostInnerItems.dataType : var.dataType;
-        Optional<Schema> referencedSchema = ModelUtils.getSchemas(openAPI).entrySet().stream()
-                .filter(entry -> Objects.equals(varDataType, toModelName(entry.getKey())))
-                .map(Map.Entry::getValue)
-                .findFirst();
-        String dataType = (referencedSchema.isPresent()) ? getTypeDeclaration(referencedSchema.get()) : varDataType;
+        Schema referencedSchema = getModelNameToSchemaCache().get(varDataType);
+        String dataType = (referencedSchema != null) ? getTypeDeclaration(referencedSchema) : varDataType;
 
         // put "enumVars" map into `allowableValues", including `name` and `value`
         List<Map<String, Object>> enumVars = buildEnumVars(values, dataType);
 
         // if "x-enum-varnames" or "x-enum-descriptions" defined, update varnames
         Map<String, Object> extensions = var.mostInnerItems != null ? var.mostInnerItems.getVendorExtensions() : var.getVendorExtensions();
-        if (referencedSchema.isPresent()) {
-            extensions = referencedSchema.get().getExtensions();
+        if (referencedSchema != null) {
+            extensions = referencedSchema.getExtensions();
         }
         updateEnumVarsWithExtensions(enumVars, extensions);
         allowableValues.put("enumVars", enumVars);

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/StringUtils.java

@@ -7,10 +7,13 @@ import org.apache.commons.lang3.tuple.ImmutablePair;
 import org.apache.commons.lang3.tuple.Pair;
 import org.openapitools.codegen.config.GlobalSettings;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
 import java.util.HashMap;
+import java.util.Objects;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -18,11 +21,11 @@ import java.util.regex.Pattern;
 public class StringUtils {
 
     /**
-     * Set the cache size (entry count) of the sanitizedNameCache, camelizedWordsCache and underscoreWords.
+     * Set the cache size (entry count) of the sanitizedNameCache, camelizedWordsCache and underscoreWordsCache.
      */
     public static final String NAME_CACHE_SIZE_PROPERTY = "org.openapitools.codegen.utils.namecache.cachesize";
     /**
-     * Set the cache expiry (in seconds) of the sanitizedNameCache, camelizedWordsCache and underscoreWords.
+     * Set the cache expiry (in seconds) of the sanitizedNameCache, camelizedWordsCache and underscoreWordsCache.
      */
     public static final String NAME_CACHE_EXPIRY_PROPERTY = "org.openapitools.codegen.utils.namecache.expireafter.seconds";
 
@@ -31,7 +34,11 @@ public class StringUtils {
     private static Cache<Pair<String, Boolean>, String> camelizedWordsCache;
 
     // A cache of underscored words, used to optimize the performance of the underscore() method.
-    private static Cache<String, String> underscoreWords;
+    private static Cache<String, String> underscoreWordsCache;
+
+    // A cache of escaped words, used to optimize the performance of the escape() method.
+    private static Cache<EscapedNameOptions, String> escapedWordsCache;
+
     static {
         int cacheSize = Integer.parseInt(GlobalSettings.getProperty(NAME_CACHE_SIZE_PROPERTY, "200"));
         int cacheExpiry = Integer.parseInt(GlobalSettings.getProperty(NAME_CACHE_EXPIRY_PROPERTY, "5"));
@@ -41,13 +48,24 @@ public class StringUtils {
                 .ticker(Ticker.systemTicker())
                 .build();
 
-        underscoreWords = Caffeine.newBuilder()
+        escapedWordsCache = Caffeine.newBuilder()
+                .maximumSize(cacheSize)
+                .expireAfterAccess(cacheExpiry, TimeUnit.SECONDS)
+                .ticker(Ticker.systemTicker())
+                .build();
+
+        underscoreWordsCache = Caffeine.newBuilder()
                 .maximumSize(cacheSize)
                 .expireAfterAccess(cacheExpiry, TimeUnit.SECONDS)
                 .ticker(Ticker.systemTicker())
                 .build();
     }
 
+    private static Pattern capitalLetterPattern = Pattern.compile("([A-Z]+)([A-Z][a-z])");
+    private static Pattern lowercasePattern = Pattern.compile("([a-z\\d])([A-Z])");
+    private static Pattern pkgSeparatorPattern = Pattern.compile("\\.");
+    private static Pattern dollarPattern = Pattern.compile("\\$");
+
     /**
      * Underscore the given word.
      * Copied from Twitter elephant bird
@@ -57,18 +75,16 @@ public class StringUtils {
      * @return The underscored version of the word
      */
     public static String underscore(final String word) {
-        return underscoreWords.get(word, wordToUnderscore -> {
+        return underscoreWordsCache.get(word, wordToUnderscore -> {
             String result;
-            String firstPattern = "([A-Z]+)([A-Z][a-z])";
-            String secondPattern = "([a-z\\d])([A-Z])";
             String replacementPattern = "$1_$2";
             // Replace package separator with slash.
-            result = wordToUnderscore.replaceAll("\\.", "/");
+            result = pkgSeparatorPattern.matcher(wordToUnderscore).replaceAll("/");
             // Replace $ with two underscores for inner classes.
-            result = result.replaceAll("\\$", "__");
+            result = dollarPattern.matcher(result).replaceAll("__");
             // Replace capital letter with _ plus lowercase letter.
-            result = result.replaceAll(firstPattern, replacementPattern);
-            result = result.replaceAll(secondPattern, replacementPattern);
+            result = capitalLetterPattern.matcher(result).replaceAll(replacementPattern);
+            result = lowercasePattern.matcher(result).replaceAll(replacementPattern);
             result = result.replace('-', '_');
             // replace space with underscore
             result = result.replace(' ', '_');
@@ -103,6 +119,8 @@ public class StringUtils {
     private static Pattern camelizeUppercasePattern = Pattern.compile("(\\.?)(\\w)([^\\.]*)$");
     private static Pattern camelizeUnderscorePattern = Pattern.compile("(_)(.)");
     private static Pattern camelizeHyphenPattern = Pattern.compile("(-)(.)");
+    private static Pattern camelizeDollarPattern = Pattern.compile("\\$");
+    private static Pattern camelizeSimpleUnderscorePattern = Pattern.compile("_");
 
     /**
      * Camelize name (parameter, property, method, etc)
@@ -144,7 +162,7 @@ public class StringUtils {
             m = camelizeUppercasePattern.matcher(word);
             if (m.find()) {
                 String rep = m.group(1) + m.group(2).toUpperCase(Locale.ROOT) + m.group(3);
-                rep = rep.replaceAll("\\$", "\\\\\\$");
+                rep = camelizeDollarPattern.matcher(rep).replaceAll("\\\\\\$");
                 word = m.replaceAll(rep);
             }
 
@@ -154,7 +172,7 @@ public class StringUtils {
                 String original = m.group(2);
                 String upperCase = original.toUpperCase(Locale.ROOT);
                 if (original.equals(upperCase)) {
-                    word = word.replaceFirst("_", "");
+                    word = camelizeSimpleUnderscorePattern.matcher(word).replaceFirst("");
                 } else {
                     word = m.replaceFirst(upperCase);
                 }
@@ -180,11 +198,49 @@ public class StringUtils {
             }
 
             // remove all underscore
-            word = word.replaceAll("_", "");
+            word = camelizeSimpleUnderscorePattern.matcher(word).replaceAll("");
             return word;
         });
     }
 
+    private static class EscapedNameOptions {
+        public EscapedNameOptions(String name, Set<String> specialChars, List<String> charactersToAllow, String appendToReplacement) {
+            this.name = name;
+            this.appendToReplacement = appendToReplacement;
+            if (specialChars != null) {
+                this.specialChars = Collections.unmodifiableSet(specialChars);
+            } else {
+                this.specialChars = Collections.emptySet();
+            }
+            if (charactersToAllow != null) {
+                this.charactersToAllow = Collections.unmodifiableList(charactersToAllow);
+            } else {
+                this.charactersToAllow = Collections.emptyList();
+            }
+        }
+
+        private String name;
+        private String appendToReplacement;
+        private Set<String> specialChars;
+        private List<String> charactersToAllow;
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            EscapedNameOptions that = (EscapedNameOptions) o;
+            return Objects.equals(name, that.name) &&
+                    Objects.equals(appendToReplacement, that.appendToReplacement) &&
+                    Objects.equals(specialChars, that.specialChars) &&
+                    Objects.equals(charactersToAllow, that.charactersToAllow);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(name, appendToReplacement, specialChars, charactersToAllow);
+        }
+    }
+
     /**
      * Return the name with escaped characters.
      *
@@ -196,8 +252,10 @@ public class StringUtils {
      * <p>
      * throws Runtime exception as word is not escaped properly.
      */
-    public static String escape(String name, Map<String, String> replacementMap,
-                                List<String> charactersToAllow, String appendToReplacement) {
+    public static String escape(final String name, final Map<String, String> replacementMap,
+                                final List<String> charactersToAllow, final String appendToReplacement) {
+        EscapedNameOptions ns = new EscapedNameOptions(name, replacementMap.keySet(), charactersToAllow, appendToReplacement);
+        return escapedWordsCache.get(ns, wordToEscape -> {
             String result = name.chars().mapToObj(c -> {
                 String character = "" + (char) c;
                 if (charactersToAllow != null && charactersToAllow.contains(character)) {
@@ -211,5 +269,6 @@ public class StringUtils {
     
             if (result != null) return result;
             throw new RuntimeException("Word '" + name + "' could not be escaped.");    
+        });
     }
 }