Implement fromEnvironment on bool, int and String

runtime/lib/integers.cc

Index: runtime/lib/integers.cc
diff --git a/runtime/lib/integers.cc b/runtime/lib/integers.cc
index 8df13969a51561e12272fbe6d073b603be4c29e6..1f4d61a5028940720cdc1168c2e0cb02771b0c29 100644
--- a/runtime/lib/integers.cc
+++ b/runtime/lib/integers.cc
@@ -4,9 +4,12 @@
 
 #include "vm/bootstrap_natives.h"
 
+#include "include/dart_api.h"
 #include "vm/bigint_operations.h"
 #include "vm/dart_entry.h"
+#include "vm/dart_api_impl.h"
 #include "vm/exceptions.h"
+#include "vm/isolate.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
@@ -226,6 +229,63 @@ DEFINE_NATIVE_ENTRY(Integer_parse, 1) {
 }
 
 
+DEFINE_NATIVE_ENTRY(Integer_fromEnvironment, 3) {
+  GET_NON_NULL_NATIVE_ARGUMENT(String, name, arguments->NativeArgAt(1));
+  GET_NATIVE_ARGUMENT(Integer, default_value, arguments->NativeArgAt(2));
+  // Call the embedder to supply us with the environment.
+  Dart_ConfigCallback callback = isolate->config_callback();
+  if (callback != NULL) {
+    Dart_Handle result = callback(Api::NewHandle(isolate, name.raw()));
+    if (Dart_IsError(result)) {
+      const Object& error =
+          Object::Handle(isolate, Api::UnwrapHandle(result));
+      Exceptions::ThrowArgumentError(
+          String::Handle(
+              String::New(Error::Cast(error).ToErrorCString())));
+    }
+    if (Dart_IsString(result)) {
+      intptr_t digits_len;
+      Dart_StringLength(result, &digits_len);
+      if (digits_len > 0) {
+        // Check for valid integer literal before constructing integer object.
+        const char *digits;
+        Dart_StringToCString(result, &digits);

[Ivan Posva, 2013/10/30 20:44:43]

You will have a problem here if the string contains non ASCII characters since
digits_len will not match what Dart_StringToCString will return. I suggest to
use Dart_StringToUTF8 in this case.

[Søren Gjesse, 2013/10/30 21:24:34]

Good catch. Fixed.

+        // Skip leading minus if present.
+        if (*digits == '-') {
+          digits++;
+          digits_len--;
+        }
+        // Check remaining string for decimal or hex-decimal literal.
+        bool is_number = true;
+        if (digits_len > 2 &&
+            digits[0] == '0' &&
+            (digits[1] == 'x' || digits[1] == 'X')) {
+          for (int i = 2; i < digits_len && is_number; i++) {
+            is_number = ('0' <= digits[i] && digits[i] <= '9') ||
+                        ('A' <= digits[i] && digits[i] <= 'F') ||
+                        ('a' <= digits[i] && digits[i] <= 'f');
+          }
+        } else {
+          for (int i = 0; i < digits_len && is_number; i++) {
+            is_number = '0' <= digits[i] && digits[i] <= '9';
+          }
+        }
+        if (digits_len > 0 && is_number) {

[Ivan Posva, 2013/10/30 20:44:43]

Isn't digits_len > 0 guaranteed at this point?

[Søren Gjesse, 2013/10/30 21:24:34]

No, in case of leading "-" the length is decremented above (these is a test with
-Db=-.

+          const Object& value =
+              Object::Handle(isolate, Api::UnwrapHandle(result));
+          ASSERT(value.IsString());
+          return Integer::NewCanonical(String::Cast(value));
+        }
+      }
+    } else if (!Dart_IsNull(result)) {
+      Exceptions::ThrowArgumentError(
+          String::Handle(String::New("Illegal environment value")));
+    }
+  }
+  return default_value.raw();
+}
+
+
 // Passing true for 'silent' prevents throwing JavascriptIntegerOverflow.
 static RawInteger* ShiftOperationHelper(Token::Kind kind,
                                         const Integer& value,