JS: Move getMegabyteCountFromPrefixedEnv into a shared place

Author: asgerf

javascript/extractor/src/com/semmle/js/extractor/EnvironmentVariables.java

@@ -1,13 +1,14 @@
 package com.semmle.js.extractor;
 
+import com.semmle.util.data.UnitParser;
 import com.semmle.util.exception.UserError;
 import com.semmle.util.process.Env;
 import com.semmle.util.process.Env.Var;
 
 public class EnvironmentVariables {
   public static final String CODEQL_EXTRACTOR_JAVASCRIPT_ROOT_ENV_VAR =
       "CODEQL_EXTRACTOR_JAVASCRIPT_ROOT";
- 
+
   public static final String CODEQL_EXTRACTOR_JAVASCRIPT_SCRATCH_DIR_ENV_VAR =
       "CODEQL_EXTRACTOR_JAVASCRIPT_SCRATCH_DIR";
 
@@ -19,6 +20,36 @@ public class EnvironmentVariables {
 
   public static final String CODEQL_DIST_ENV_VAR = "CODEQL_DIST";
 
+  /**
+   * Returns a number of megabytes by reading an environment variable with the given suffix,
+   * or the default value if not set.
+   * <p>
+   * The following prefixes are tried:
+   * <code>CODEQL_EXTRACTOR_JAVASCRIPT_</code>,
+   * <code>LGTM_</code>,
+   * <code>SEMMLE_</code>.
+   */
+  public static int getMegabyteCountFromPrefixedEnv(String suffix, int defaultValue) {
+    String envVar = "CODEQL_EXTRACTOR_JAVASCRIPT_" + suffix;
+    String value = Env.systemEnv().get(envVar);
+    if (value == null || value.length() == 0) {
+      envVar = "LGTM_" + suffix;
+      value = Env.systemEnv().get(envVar);
+    }
+    if (value == null || value.length() == 0) {
+      envVar = "SEMMLE_" + suffix;
+      value = Env.systemEnv().get(envVar);
+    }
+    if (value == null || value.length() == 0) {
+      return defaultValue;
+    }
+    Integer amount = UnitParser.parseOpt(value, UnitParser.MEGABYTES);
+    if (amount == null) {
+      throw new UserError("Invalid value for " + envVar + ": '" + value + "'");
+    }
+    return amount;
+  }
+
   /**
    * Gets the extractor root based on the <code>CODEQL_EXTRACTOR_JAVASCRIPT_ROOT</code> or <code>
    * SEMMLE_DIST</code> or environment variable, or <code>null</code> if neither is set.

javascript/extractor/src/com/semmle/ts/extractor/TypeScriptParser.java

@@ -273,32 +273,15 @@ private List<String> getNodeJsRuntimeInvocation(String... args) {
     return result;
   }
 
-  private static int getMegabyteCountFromPrefixedEnv(String suffix, int defaultValue) {
-    String envVar = "SEMMLE_" + suffix;
-    String value = Env.systemEnv().get(envVar);
-    if (value == null || value.length() == 0) {
-      envVar = "LGTM_" + suffix;
-      value = Env.systemEnv().get(envVar);
-    }
-    if (value == null || value.length() == 0) {
-      return defaultValue;
-    }
-    Integer amount = UnitParser.parseOpt(value, UnitParser.MEGABYTES);
-    if (amount == null) {
-      throw new UserError("Invalid value for " + envVar + ": '" + value + "'");
-    }
-    return amount;
-  }
-
   /** Start the Node.js parser wrapper process. */
   private void setupParserWrapper() {
     verifyNodeInstallation();
 
     int mainMemoryMb =
         typescriptRam != 0
             ? typescriptRam
-            : getMegabyteCountFromPrefixedEnv(TYPESCRIPT_RAM_SUFFIX, 2000);
-    int reserveMemoryMb = getMegabyteCountFromPrefixedEnv(TYPESCRIPT_RAM_RESERVE_SUFFIX, 400);
+            : EnvironmentVariables.getMegabyteCountFromPrefixedEnv(TYPESCRIPT_RAM_SUFFIX, 2000);
+    int reserveMemoryMb = EnvironmentVariables.getMegabyteCountFromPrefixedEnv(TYPESCRIPT_RAM_RESERVE_SUFFIX, 400);
 
     System.out.println("Memory for TypeScript process: " + mainMemoryMb + " MB, and " + reserveMemoryMb + " MB reserve");