It is a requirement for parsing code to handle packed and unpacked
forms on the wire for repeated packable fields. This change aligns
the javanano's behavior with the java's.

Bonus: optimize array length calculation when parsing repeated
fixed-size-element-type fields.

Bonus 2: lose "xMemoizedSerializedSize" for repeated enum fields,
and make the serialized size calculation match that for repeated
int32 fields.

Change-Id: I8a06103d9290234adb46b0971b5ed155544fe86a

The output of toString is now aligned with that used by non-nano and C++
runtimes, with the exception of groups. Groups should be serialized using a
camelized name (e.g. "FooBar" rather than "foo_bar") however the nano runtime
does not have information on which fields are groups.

Changes are:
  - bytes fields are output within double-quotes, non-printable characters are
    output as octal escape sequences (i.e. \NNN);
  - field identifiers are output in underscored format;
  - unset fields are not output (rather than printing "null");
  - the type name of the root message is not output.

With these changes the nano toString, normal toString, and C++'s DebugString all
produce equivalent output when given the same message. (Provided that message
uses no deprecated features.)

Change-Id: Id4791d73822846db29344db9f7bc3781c3e183a6

Follow upstream where they have any changes in 2.5.0

Change-Id: I3466e9c11242f533a9dff8c1afef4202dd100f2e

- Migrates getCachedSize to the MessageNano parent class to save one method per message.
- Create ExtendableMessageNano parent class for protos with extensions, this saves the
getExtension and setExtension methods on the relevant messages.
- getSerializedSize's default case (with no fields to serialize) also migrate to the
parent class, which saves methods on empty messages.
- Container classes become interfaces to save the constructor.

Change-Id: I81f1a1b6d6a660096835e9df3ea20456655aab4a

Strip the null elements out before serializing the array.
This is helpful in the cases where the user wants to construct
an array of an inexact size for serialization. For example:
User constructs array of size 5 because they anticipate adding
more than 1 element before serialization. Only 3 get added, so
the array looks like [Obj, Obj, Obj, null, null]. This would
curently crash without this CL.

All repeated fields of ref-type elements can contain null
elements: repeated strings, repeated bytes, and repeated
messages/groups.

Change-Id: I117391c868c9a436536d70d6151780e9cc7e8227

Conflicts:
	src/google/protobuf/compiler/javanano/javanano_message_field.cc

The option is only called 'generate_equals' because:
- equals() is the main thing; hashCode() is there only to
  complement equals();
- it's shorter;
- toString() should not be included in this option because
  it's more for debugging and it's more likely to stop
  ProGuard from working well.

Also shortened the "has bit" expression; was
((bitField & mask) == mask), now ((bitField & mask) != 0).
Both the Java code and the bytecode are slightly shorter.

Change-Id: Ic309a08a60883bf454eb6612679aa99611620e76

* commit '42be1e79ccd670be36220222936aa7cacc6856f6':
  Feature request: set() and clear() accessors return this

Also pre-inlines set() and has() in serialization code. This could
theoretically help ProGuard: the message class size is usually large,
and because of this only, it may refuse to inline an accessor into
the serialization code, and as a result keeps the accessor intact.
Chances are, after pre-inlining all accessor calls within the message
class, those accessors become unused or single-use, so there are more
reasons for ProGuard to inline and then remove them.

Change-Id: I57decbe0b2533c1be21439de0aad15f49c7024dd

* commit 'c50f605c572a425b2fa696fedc5e61ac6f66d2a9':
  Make generated code more aligned with Google Java style.

- Blank line after opening a message class (but not an enum interface).
- Let all code blocks insert blank lines before themselves. This applies to
  'package' statement, all message classes, enum classes or constant groups,
  extensions, bitfields, proto fields (one block per field; i.e. accessors
  don't have blank lines among them), and basic MessageNano methods. In this
  case we don't need to guess what the next block is and create blank lines
  for it.
- Fixed some newline/indent errors.
- Only one SuppressWarnings("hiding") per file.

Change-Id: I865f52ad4fb6ea3b3a98b97ac9d78d19fc46c858

* commit 'afaf74ce55f4aff63dc30e7045a7cd6c1cf232dc':
  Fix repeated field merging semantics.

The public doc states that repeated fields are simply concatenated
and doesn't impose a different semantics for packed fields. This
CL fixes this for packed fields and adds tests covering all cases.

Also fixed a bit of missed null-repeated-field treatments.

Change-Id: Ie35277bb1a9f0b8171dc9d07b6adf9b9d3308de2

* commit '63e819adbb4d2d8215f5d3d8297dc50bf2fe3329':
  Protect against null repeated fields.

* commit 'c85806baedfc98ad5759a990b35ea5b5f1ac4edb':

There's no distinction between a repeated field being null and being
empty. In both cases, nothing is sent on the wire. Clients might for
whatever reason inadvertently set a repeated field to null, so
protect against that and treat it just as if the field was empty.

Change-Id: Ic3846f7f2189d6cfff6f8ef3ca217daecc3c8be7

* commit '39cee9f1f5cd513a53ac5100eb208ed431f99af0':
  Remove all field initializers and let ctor call clear().

The field initializers have basically caused the compiled <init> method
to inline the whole clear() method, which means if ProGuard is not used
or failed to inline or remove clear(), there are two big chunks of code
that do the same thing. So why not just call clear() from the ctor.

Change-Id: Ief71e2b03db2e059b3bfa98309649368089ffab0

* commit 'cbb08132821cb56f4e6c5e5f8a0b32f51879782a':
  Add missing README parts for enum_style and in-repo usage

Change-Id: I7934a5b0444017aeda787501ebf8d9f9ba295c73

* commit 'c4a1b547c91178d79f5d2cc2e00b8be922c22fe8':
  Add reftypes field generator option.

* commit '44cbb06c725fbba00464bba9f19dc0ea295406b1':
  Fix some indenting issues with set__() function

Previously it looked like this:

public final class OuterClass {
  [...]
  public static final class InnerClass extends
      com.google.protobuf.nano.MessageNano {
    [...]
    public void setId(java.lang.String value) {
      if (value == null) {
    throw new java.lang.NullPointerException();
  }
  id_ = value;
      bitfield0_ |= 0x00000001;
    [...]
  }
  [...]
}

Now it looks like this:

public final class OuterClass {
  [...]
  public static final class InnerClass extends
      com.google.protobuf.nano.MessageNano {
    [...]
    public void setId(java.lang.String value) {
      if (value == null) throw new java.lang.NullPointerException();
      id_ = value;
      bitfield0_ |= 0x00000001;
    [...]
  }
  [...]
}

Change-Id: I2a9289b528f785c846210d558206d677aa13e9be

This option generates fields as reference types, and serializes
based on nullness.

Change-Id: Ic32e0eebff59d14016cc9a19e15a9bb08ae0bba5
Signed-off-by: Brian Duff <bduff@google.com>

* commit '9827c718c45cfa1744a3b0f8fc27dac9cd415603':
  Fix roundtrip failure with groups when unknown fields are enabled.