Speed up BResource loading

The code to parse the resource table reads one entry at a time because
the table size isn't known. This resulted in a lot of read syscalls,
each reading just 12 bytes. Use a BBufferIO to buffer these and reduce
the number of syscalls. This helps especially when there are lot of
resources, for example in libbe with all the country flags.

It also removes some spam from strace output for all these read calls.

Change-Id: Ib165a0eacc2bc5f3d319c22c2fac4f439efbdef2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2858
Reviewed-by: Rene Gollent <rene@gollent.com>

headers/private/storage/ResourceFile.h

@@ -83,7 +83,8 @@ private:
 									const PEFContainerHeader& pefHeader);
 			void				_ReadHeader(resource_parse_info& parseInfo);
 			void				_ReadIndex(resource_parse_info& parseInfo);
-			bool				_ReadIndexEntry(resource_parse_info& parseInfo,
+			bool				_ReadIndexEntry(BPositionIO& buffer,
+									resource_parse_info& parseInfo,
 									int32 index, uint32 tableOffset,
 									bool peekAhead);
 			void				_ReadInfoTable(resource_parse_info& parseInfo);

src/build/libbe/support/Jamfile

@@ -10,6 +10,7 @@ SEARCH_SOURCE += [ FDirName $(HAIKU_TOP) src kits support ] ;
 BuildPlatformMergeObjectPIC <libbe_build>support_kit.o :
 	Archivable.cpp
 	BlockCache.cpp
+	BufferIO.cpp
 	ByteOrder.cpp
 	CompressionAlgorithm.cpp
 	DataIO.cpp

src/kits/storage/ResourceFile.cpp

@@ -17,7 +17,7 @@
 #include <stdio.h>
 
 #include <AutoDeleter.h>
-
+#include <BufferIO.h>
 #include <Elf.h>
 #include <Exception.h>
 #include <Pef.h>
@@ -781,9 +781,11 @@ ResourceFile::_ReadIndex(resource_parse_info& parseInfo)
 {
 	int32& resourceCount = parseInfo.resource_count;
 	off_t& fileSize = parseInfo.file_size;
+	BBufferIO buffer(&fFile, 2048, false);
+
 	// read the header
 	resource_index_section_header header;
-	read_exactly(fFile, kResourceIndexSectionOffset, &header,
+	read_exactly(buffer, kResourceIndexSectionOffset, &header,
 		kResourceIndexSectionHeaderSize,
 		"Failed to read the resource index section header.");
 	// check the header
@@ -820,6 +822,7 @@ ResourceFile::_ReadIndex(resource_parse_info& parseInfo)
 			"offset. Is: %lu, should be: %lu.",
 			unknownSectionOffset, kUnknownResourceSectionSize);
 	}
+
 	// info table offset and size
 	uint32 infoTableOffset = _GetInt(header.rish_info_table_offset);
 	uint32 infoTableSize = _GetInt(header.rish_info_table_size);
@@ -827,6 +830,7 @@ ResourceFile::_ReadIndex(resource_parse_info& parseInfo)
 		throw Exception(B_IO_ERROR, "Invalid info table location.");
 	parseInfo.info_table_offset = infoTableOffset;
 	parseInfo.info_table_size = infoTableSize;
+
 	// read the index entries
 	uint32 indexTableOffset = indexSectionOffset
 		+ kResourceIndexSectionHeaderSize;
@@ -836,8 +840,8 @@ ResourceFile::_ReadIndex(resource_parse_info& parseInfo)
 	bool tableEndReached = false;
 	for (int32 i = 0; !tableEndReached && i < maxResourceCount; i++) {
 		// read one entry
-		tableEndReached = !_ReadIndexEntry(parseInfo, i, indexTableOffset,
-			(i >= resourceCount));
+		tableEndReached = !_ReadIndexEntry(buffer, parseInfo, i,
+			indexTableOffset, (i >= resourceCount));
 		if (!tableEndReached)
 			actualResourceCount++;
 	}
@@ -855,41 +859,37 @@ ResourceFile::_ReadIndex(resource_parse_info& parseInfo)
 
 
 bool
-ResourceFile::_ReadIndexEntry(resource_parse_info& parseInfo, int32 index,
-	uint32 tableOffset, bool peekAhead)
+ResourceFile::_ReadIndexEntry(BPositionIO& buffer,
+	resource_parse_info& parseInfo, int32 index, uint32 tableOffset,
+	bool peekAhead)
 {
 	off_t& fileSize = parseInfo.file_size;
-	//
 	bool result = true;
 	resource_index_entry entry;
+
 	// read one entry
 	off_t entryOffset = tableOffset + index * kResourceIndexEntrySize;
-	read_exactly(fFile, entryOffset, &entry, kResourceIndexEntrySize,
+	read_exactly(buffer, entryOffset, &entry, kResourceIndexEntrySize,
 		"Failed to read a resource index entry.");
+
 	// check, if the end is reached early
 	if (result && check_pattern(entryOffset, &entry,
 			kResourceIndexEntrySize / 4, fHostEndianess)) {
-		if (!peekAhead) {
-//			Warnings::AddCurrentWarning("Unexpected end of resource index "
-//										"table at index: %ld (/%ld).",
-//										index + 1, resourceCount);
-		}
 		result = false;
 	}
 	uint32 offset = _GetInt(entry.rie_offset);
 	uint32 size = _GetInt(entry.rie_size);
+
 	// check the location
 	if (result && offset + size > fileSize) {
-		if (peekAhead) {
-//			Warnings::AddCurrentWarning("Invalid data after resource index "
-//										"table.");
-		} else {
+		if (!peekAhead) {
 			throw Exception(B_IO_ERROR, "Invalid resource index entry: index: "
 				"%ld, offset: %lu (%lx), size: %lu (%lx).", index + 1, offset,
 				offset, size, size);
 		}
 		result = false;
 	}
+
 	// add the entry
 	if (result) {
 		ResourceItem* item = new(std::nothrow) ResourceItem;
@@ -901,6 +901,7 @@ ResourceFile::_ReadIndexEntry(resource_parse_info& parseInfo, int32 index,
 			throw Exception(B_NO_MEMORY);
 		}
 	}
+
 	return result;
 }