/// <summary></summary>
/// <param name="reader"></param>
/// <returns>false if we reached end of file. If result is true, the caller is
/// expected to invoke us again for next section discovery.</returns>
private bool ParseSection(BinaryParsingReader reader)
{
SectionTypes sectionType;
try {
sectionType = (SectionTypes)reader.ReadVarUint7();
if (!Enum.IsDefined(typeof(SectionTypes), sectionType))
{
throw new WasmParsingException(string.Format(
ParsingErrorMessages.UnknownSectionType, sectionType));
}
Console.WriteLine("Parsing {0} section.", sectionType);
}
catch (EndOfStreamException e) {
// This is expected. Section parsing is complete.
return(false);
}
try {
ParseSection(reader, sectionType);
return(true);
}
catch (EndOfStreamException e) {
// This is unexpected. We are stopping in the midst of a section.
throw new WasmParsingException(ParsingErrorMessages.IncompleteSectionEncountered);
}
}
private void ParseImportSection(BinaryParsingReader reader, uint payloadSize)
{
long startPosition = payloadSize;
uint importsCount = reader.ReadVarUint32();
for (uint index = 0; index < importsCount; index++)
{
string moduleName = reader.ReadLengthPrefixedUTF8String();
List <ImportedItemDefinition> imports;
if (!_perModuleImportedItems.TryGetValue(moduleName, out imports))
{
imports = new List <ImportedItemDefinition>();
_perModuleImportedItems.Add(moduleName, imports);
}
string fieldName = reader.ReadLengthPrefixedUTF8String();
ExternalKind kind = (ExternalKind)reader.ReadVarUint7();
bool maxPresent;
uint initialLength;
uint maximumLength;
switch (kind)
{
case ExternalKind.Function:
imports.Add(new ImportedFunctionDefinition(fieldName, reader.ReadVarUint32()));
continue;
case ExternalKind.Global:
bool mutable;
BuiltinLanguageType contentType = reader.ReadGlobaltype(out mutable);
imports.Add(new ImportedGlobalDefinition(fieldName, contentType, mutable));
continue;
case ExternalKind.Memory:
maxPresent = (0 != reader.ReadVarUint1());
initialLength = reader.ReadVarUint32();
maximumLength = maxPresent ? reader.ReadVarUint32() : 0;
imports.Add(new ImportedMemoryDefinition(fieldName, initialLength, maxPresent ? (uint?)maximumLength : null));
continue;
case ExternalKind.Table:
BuiltinLanguageType elementType = (BuiltinLanguageType)reader.ReadVarInt7();
if (BuiltinLanguageType.AnyFunc != elementType)
{
throw new WasmParsingException(string.Format(ParsingErrorMessages.UnexpectedBuiltinType,
elementType, BuiltinLanguageType.AnyFunc));
}
maxPresent = (0 != reader.ReadVarUint1());
initialLength = reader.ReadVarUint32();
maximumLength = maxPresent ? reader.ReadVarUint32() : 0;
imports.Add(new ImportedTableDefinition(fieldName, elementType, initialLength,
maxPresent ? (uint?)maximumLength : null));
continue;
default:
throw new WasmParsingException(string.Format(
ParsingErrorMessages.UnrecognizedExternalKind, kind));
}
}
// TODO Check for match between payloadSize and current stream position.
return;
}
private void ParseDataSection(BinaryParsingReader reader, uint payloadSize)
{
uint dataSegmentsCount = reader.ReadVarUint32();
_dataSegments = new List <DataSegment>();
for (uint index = 0; index < dataSegmentsCount; index++)
{
_dataSegments.Add(DataSegment.Create(reader));
}
return;
}
private void ParseFunctionSection(BinaryParsingReader reader, uint payloadSize)
{
long startPosition = payloadSize;
uint functionsCount = reader.ReadVarUint32();
for (uint index = 0; index < functionsCount; index++)
{
uint signatureIndex = reader.ReadVarUint32();
_functions.Add(new FunctionDefinition(_functionSignatures[(int)signatureIndex]));
}
}
internal static DataSegment Create(BinaryParsingReader reader)
{
uint linearMemoryIndex = reader.ReadVarUint32();
List <Instruction> offsetExpression = reader.ReadInitializationExpression();
uint dataSize = reader.ReadVarUint32();
byte[] data = reader.ReadBytes((int)dataSize);
return(new DataSegment()
{
LinearMemoryIndex = linearMemoryIndex, Data = data, OffsetExpression = offsetExpression
});
}
private void ParseExportSection(BinaryParsingReader reader, uint payloadSize)
{
long startPosition = payloadSize;
uint exportsCount = reader.ReadVarUint32();
for (uint index = 0; index < exportsCount; index++)
{
string exportName = reader.ReadLengthPrefixedUTF8String();
// TODO : Interpret below fields.
byte exportKind = reader.ReadByte();
uint indexSpaceIndex = reader.ReadVarUint32();
}
}
/// <summary></summary>
/// <param name="from"></param>
/// <remarks>Module specification is defined by :
/// http://webassembly.org/docs/binary-encoding/#high-level-structure
/// </remarks>
private bool Parse(Stream from)
{
using (BinaryParsingReader reader = new BinaryParsingReader(from)) {
_decoder = new InstructionDecoder(reader);
ParseMagicNumberAndVersion(reader);
while (ParseSection(reader))
{
;
}
}
DumpStatistics();
return(true);
}
private void ParseTypeSection(BinaryParsingReader reader, uint payloadSize)
{
long startPosition = payloadSize;
uint functionsCount = reader.ReadVarUint32();
for (uint index = 0; index < functionsCount; index++)
{
FunctionSignature function = FunctionSignature.Parse(reader);
_functionSignatures.Add(function);
}
// TODO Check for match between payloadSize and current stream position.
return;
}
private void ParseCodeSection(BinaryParsingReader reader, uint payloadSize)
{
uint functionBodyCount = reader.ReadVarUint32();
if (functionBodyCount != _functions.Count)
{
throw new WasmParsingException(
ParsingErrorMessages.FunctionDefVsBodyCountMismatch);
}
for (uint functionIndex = 0; functionIndex < functionBodyCount; functionIndex++)
{
ParseFunctionBody(reader, _functions[(int)functionIndex]);
}
}
private void ParseGlobalSection(BinaryParsingReader reader, uint payloadSize)
{
uint globalVariablesCount = reader.ReadVarUint32();
for (uint index = 0; index < globalVariablesCount; index++)
{
bool mutable;
BuiltinLanguageType contentType = reader.ReadGlobaltype(out mutable);
List <Instruction> initializer = reader.ReadInitializationExpression();
GlobalVariable variable = new GlobalVariable(contentType, mutable, initializer);
_globalVariables.Add(variable);
}
}
private void ParseElementSection(BinaryParsingReader reader, uint payloadSize)
{
uint elementsCount = reader.ReadVarUint32();
for (uint index = 0; index < elementsCount; index++)
{
uint tableIndex = reader.ReadVarUint32();
List <Instruction> initializer = reader.ReadInitializationExpression();
uint elementCount = reader.ReadVarUint32();
for (int elementIndex = 0; elementIndex < elementCount; elementIndex++)
{
uint element = reader.ReadVarUint32();
}
}
}
internal static Element Create(BinaryParsingReader reader)
{
uint tableIndex = reader.ReadVarUint32();
List <Instruction> offsetExpression = reader.ReadInitializationExpression();
uint elementsCount = reader.ReadVarUint32();
uint[] elements = new uint[elementsCount];
for (int index = 0; index < elementsCount; index++)
{
elements[index] = reader.ReadVarUint32();
}
return(new Element()
{
Elements = elements, OffsetExpression = offsetExpression, TableIndex = tableIndex
});
}
internal static FunctionSignature Parse(BinaryParsingReader reader)
{
FunctionSignature result = new FunctionSignature();
reader.ReadAndAssertLanguageType(-32);
uint parametersCount = reader.ReadVarUint32();
for (uint index = 0; index < parametersCount; index++)
{
result._parametersType.Add((BuiltinLanguageType)reader.ReadValueType());
}
result.ReturnType = (1 == reader.ReadVarUint1())
? (BuiltinLanguageType)reader.ReadValueType()
: BuiltinLanguageType.EmptyBlock;
return(result);
}
private void ParseMagicNumberAndVersion(BinaryParsingReader reader)
{
int magicNumber = reader.ReadInt32();
if (MagicModuleNumber != magicNumber)
{
throw new WasmParsingException(string.Format(
ParsingErrorMessages.MissingModuleMagicNumber, MagicModuleNumber, magicNumber));
}
int version = reader.ReadInt32();
if ((MaximumSupportedModuleFormatVersion < version) ||
(MinimumSupportedModuleFormatVersion > version))
{
throw new WasmParsingException(string.Format(
ParsingErrorMessages.UnsupportedModuleFormatVersion,
version, MinimumSupportedModuleFormatVersion, MaximumSupportedModuleFormatVersion));
}
}
private void ParseFunctionBody(BinaryParsingReader reader, FunctionDefinition target)
{
uint bodySize = reader.ReadVarUint32();
long startPosition = reader.BaseStream.Position;
uint localsEntryCount = reader.ReadVarUint32();
lock (_currentFunctionLocals) {
if (0 < localsEntryCount)
{
_currentFunctionLocals.Clear();
for (int localEntryIndex = 0; localEntryIndex < localsEntryCount; localEntryIndex++)
{
uint variablesCount = reader.ReadVarUint32();
BuiltinLanguageType valuesType = (BuiltinLanguageType)reader.ReadValueType();
for (uint index = 0; index < variablesCount; index++)
{
_currentFunctionLocals.Add(valuesType);
}
}
target.SetLocalTypes(_currentFunctionLocals.ToArray());
}
}
List <Instruction> instructions = reader.ReadFunctionBodyCode();
long endPosition = reader.BaseStream.Position;
uint trueSize = (uint)(endPosition - startPosition);
#if TRACE_CODE
foreach (Instruction instruction in instructions)
{
Console.WriteLine(instruction.ToString());
}
Console.WriteLine("{0} ================================================", target.Id);
#endif
if (bodySize != trueSize)
{
throw new WasmParsingException(string.Format(
ParsingErrorMessages.FunctionBodyLengthMismatch, bodySize, trueSize));
}
target.SetBody(instructions);
return;
}
internal InstructionDecoder(BinaryParsingReader reader)
{
_reader = reader;
}
private WasmModuleSection ParseSection(BinaryParsingReader reader, SectionTypes type)
{
WasmModuleSection result = null;
// The specification is not very clear about the fact that the value of the
// payload_len field from section header doesn't include neither this field
// length, nor the previous section code. We have to read the payload_data
// field definition to understand this.
uint payloadSize = reader.ReadVarUint32();
string sectionName = null;
if (0 == type)
{
long initialStreamPosition = reader.BaseStream.Position;
sectionName = reader.ReadLengthPrefixedUTF8String();
payloadSize -= (uint)(reader.BaseStream.Position - initialStreamPosition);
result = new WasmModuleSection(sectionName);
byte[] sectionData = new byte[payloadSize];
reader.Read(sectionData, 0, sectionData.Length);
result.SetRawData(sectionData);
_customSections.Add(result);
return(result);
}
// This test will ensure a non custom section can't be parsed twice as per
// the specification. We seems to be more stringent here than the specification
// that seems to state that the section COULD be ignored.
if (type <= _lastParsedSectionType)
{
throw new WasmParsingException(string.Format(ParsingErrorMessages.InvalidSectionDefinitionOrder,
type, _lastParsedSectionType));
}
switch (type)
{
case SectionTypes.Code:
ParseCodeSection(reader, payloadSize);
break;
case SectionTypes.Data:
ParseDataSection(reader, payloadSize);
break;
case SectionTypes.Element:
ParseElementSection(reader, payloadSize);
break;
case SectionTypes.Export:
ParseExportSection(reader, payloadSize);
break;
case SectionTypes.Function:
ParseFunctionSection(reader, payloadSize);
break;
case SectionTypes.Global:
ParseGlobalSection(reader, payloadSize);
break;
case SectionTypes.Import:
ParseImportSection(reader, payloadSize);
break;
case SectionTypes.Memory:
throw new NotImplementedException();
case SectionTypes.Start:
throw new NotImplementedException();
case SectionTypes.Table:
throw new NotImplementedException();
case SectionTypes.Type:
ParseTypeSection(reader, payloadSize);
break;
default:
throw new NotImplementedException();
}
_lastParsedSectionType = type;
return(result);
}
