Merge pull request #229 from p-x9/feature/local-symbol-for-image-in-cache

Enhance `DyldCacheLocalSymbolsInfo`

Author: p-x9

Sources/MachOKit/DyldCache.swift

@@ -196,7 +196,10 @@ extension DyldCache {
             }
             let suffix = ".symbols"
             let path = url.path + suffix
-            return try .init(url: .init(fileURLWithPath: path))
+            return try .init(
+                subcacheUrl: .init(fileURLWithPath: path),
+                mainCacheHeader: mainCacheHeader
+            )
         }
     }
 

Sources/MachOKit/Model/DyldCache/DyldCacheLocalSymbolsInfo.swift

@@ -338,3 +338,92 @@ extension DyldCacheLocalSymbolsInfo {
         }
     }
 }
+
+extension DyldCacheLocalSymbolsInfo {
+    public func entry64(
+        for machO: MachOFile,
+        in cache: DyldCache
+    ) -> DyldCacheLocalSymbolsEntry64? {
+        guard let offset = machO.textOffset(in: cache) else { return nil }
+        return entries64(in: cache)?.first(
+            where: {
+                $0.dylibOffset == offset
+            }
+        )
+    }
+
+    public func entry32(
+        for machO: MachOFile,
+        in cache: DyldCache
+    ) -> DyldCacheLocalSymbolsEntry? {
+        guard let offset = machO.textOffset(in: cache) else { return nil }
+        return entries32(in: cache)?.first(
+            where: {
+                $0.dylibOffset == offset
+            }
+        )
+    }
+
+    public func entry(
+        for machO: MachOFile,
+        in cache: DyldCache
+    ) -> (any DyldCacheLocalSymbolsEntryProtocol)? {
+        guard let offset = machO.textOffset(in: cache) else { return nil }
+        return entries(in: cache).first(
+            where: {
+                $0.dylibOffset == offset
+            }
+        )
+    }
+}
+
+extension DyldCacheLocalSymbolsInfo {
+    public func entry64(
+        for machO: MachOFile,
+        in cache: FullDyldCache
+    ) -> DyldCacheLocalSymbolsEntry64? {
+        guard let offset = machO.textOffset(in: cache) else { return nil }
+        return entries64(in: cache)?.first(
+            where: {
+                $0.dylibOffset == offset
+            }
+        )
+    }
+
+    public func entry32(
+        for machO: MachOFile,
+        in cache: FullDyldCache
+    ) -> DyldCacheLocalSymbolsEntry? {
+        guard let offset = machO.textOffset(in: cache) else { return nil }
+        return entries32(in: cache)?.first(
+            where: {
+                $0.dylibOffset == offset
+            }
+        )
+    }
+
+    public func entry(
+        for machO: MachOFile,
+        in cache: FullDyldCache
+    ) -> (any DyldCacheLocalSymbolsEntryProtocol)? {
+        guard let offset = machO.textOffset(in: cache) else { return nil }
+        return entries(in: cache).first(
+            where: {
+                $0.dylibOffset == offset
+            }
+        )
+    }
+}
+
+fileprivate extension MachOFile {
+    func textOffset(in cache: DyldCache) -> UInt64? {
+        let loadCommands = loadCommands
+        let text: (any SegmentCommandProtocol)? = loadCommands.text64 ?? loadCommands.text
+        guard let text else { return nil }
+        return numericCast(text.virtualMemoryAddress) - cache.mainCacheHeader.sharedRegionStart
+    }
+
+    func textOffset(in cache: FullDyldCache) -> UInt64? {
+        textOffset(in: cache.mainCache)
+    }
+}

Sources/MachOKit/Protocol/DyldCacheLocalSymbolsEntryProtocol.swift

@@ -18,3 +18,9 @@ public protocol DyldCacheLocalSymbolsEntryProtocol {
     /// Number of local symbols for this dylib
     var nlistCount: Int { get }
 }
+
+extension DyldCacheLocalSymbolsEntryProtocol {
+    public var nlistRange: Range<Int> {
+        nlistStartIndex ..< nlistStartIndex + nlistCount
+    }
+}

Tests/MachOKitTests/DyldCachePrintTests.swift

@@ -152,6 +152,28 @@ final class DyldCachePrintTests: XCTestCase {
         }
     }
 
+    func testLocalSymbolsInSymbolCache() throws {
+        guard let symbolCache = try cache.symbolCache else {
+            return
+        }
+        guard let info = symbolCache.localSymbolsInfo else {
+            return
+        }
+        let machO = cache.machOFiles().first(
+            where: {
+                $0.imagePath.contains("/SwiftUICore")
+            }
+        )!
+        guard let entry = info.entry(for: machO, in: symbolCache) else {
+            XCTFail("No entry found")
+            return
+        }
+        let symbols = Array(info.symbols(in: symbolCache))[entry.nlistRange]
+        for symbol in symbols.prefix(100) {
+            print(symbol.name)
+        }
+    }
+
     func testMachOFiles() throws {
         let machOs = cache.machOFiles()
         for machO in machOs {

Tests/MachOKitTests/FullDyldCachePrintTests.swift

@@ -148,6 +148,28 @@ final class FullDyldCachePrintTests: XCTestCase {
         }
     }
 
+    func testLocalSymbolsInSymbolCache() throws {
+        guard let symbolCache = try cache.symbolCache else {
+            return
+        }
+        guard let info = symbolCache.localSymbolsInfo else {
+            return
+        }
+        let machO = cache.machOFiles().first(
+            where: {
+                $0.imagePath.contains("/SwiftUICore")
+            }
+        )!
+        guard let entry = info.entry(for: machO, in: symbolCache) else {
+            XCTFail("No entry found")
+            return
+        }
+        let symbols = Array(info.symbols(in: symbolCache))[entry.nlistRange]
+        for symbol in symbols.prefix(100) {
+            print(symbol.name)
+        }
+    }
+
     func testMachOFiles() throws {
         let machOs = cache.machOFiles()
         for machO in machOs {