From c7c957966acb3c166288be777025f7cea9633d68 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Sun, 14 Oct 2018 23:13:45 +0200
Subject: [PATCH] Implement SyntheticFileSystem::readInodeBytes().

---
 VirtualFileSystem/Ext2FileSystem.cpp      | 12 ++++++------
 VirtualFileSystem/SyntheticFileSystem.cpp | 18 +++++++++++++++---
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/VirtualFileSystem/Ext2FileSystem.cpp b/VirtualFileSystem/Ext2FileSystem.cpp
index c27b84e3db..f09b61e9d0 100644
--- a/VirtualFileSystem/Ext2FileSystem.cpp
+++ b/VirtualFileSystem/Ext2FileSystem.cpp
@@ -258,7 +258,7 @@ Vector<unsigned> Ext2FileSystem::blockListForInode(const ext2_inode& e2inode) co
     return list;
 }
 
-ssize_t Ext2FileSystem::readInodeBytes(InodeIdentifier inode, Unix::off_t offset, size_t count, byte* buffer) const
+Unix::ssize_t Ext2FileSystem::readInodeBytes(InodeIdentifier inode, Unix::off_t offset, Unix::size_t count, byte* buffer) const
 {
     ASSERT(offset >= 0);
     ASSERT(inode.fileSystemID() == id());
@@ -282,7 +282,7 @@ ssize_t Ext2FileSystem::readInodeBytes(InodeIdentifier inode, Unix::off_t offset
     // This avoids wasting an entire block on short links. (Most links are short.)
     static const unsigned maxInlineSymlinkLength = 60;
     if (isSymbolicLink(e2inode->i_mode) && e2inode->i_size < maxInlineSymlinkLength) {
-        ssize_t nread = min(e2inode->i_size - offset, static_cast<Unix::off_t>(count));
+        Unix::ssize_t nread = min(e2inode->i_size - offset, static_cast<Unix::off_t>(count));
         memcpy(buffer, e2inode->i_block + offset, nread);
         return nread;
     }
@@ -302,8 +302,8 @@ ssize_t Ext2FileSystem::readInodeBytes(InodeIdentifier inode, Unix::off_t offset
 
     dword offsetIntoFirstBlock = offset % blockSize();
 
-    ssize_t nread = 0;
-    size_t remainingCount = min((Unix::off_t)count, e2inode->i_size - offset);
+    Unix::ssize_t nread = 0;
+    Unix::size_t remainingCount = min((Unix::off_t)count, e2inode->i_size - offset);
     byte* out = buffer;
 
 #ifdef EXT2_DEBUG
@@ -346,7 +346,7 @@ ByteBuffer Ext2FileSystem::readInode(InodeIdentifier inode) const
 
     auto contents = ByteBuffer::createUninitialized(e2inode->i_size);
 
-    ssize_t nread;
+    Unix::ssize_t nread;
     byte buffer[512];
     byte* out = contents.pointer();
     Unix::off_t offset = 0;
@@ -501,7 +501,7 @@ public:
 
 private:
     ByteBuffer& m_buffer;
-    size_t m_offset { 0 };
+    Unix::size_t m_offset { 0 };
 };
 
 bool Ext2FileSystem::writeDirectoryInode(unsigned directoryInode, Vector<DirectoryEntry>&& entries)
diff --git a/VirtualFileSystem/SyntheticFileSystem.cpp b/VirtualFileSystem/SyntheticFileSystem.cpp
index 50a8473a90..5479933a42 100644
--- a/VirtualFileSystem/SyntheticFileSystem.cpp
+++ b/VirtualFileSystem/SyntheticFileSystem.cpp
@@ -1,4 +1,5 @@
 #include "SyntheticFileSystem.h"
+#include <AK/StdLib.h>
 
 RetainPtr<SyntheticFileSystem> SyntheticFileSystem::create()
 {
@@ -122,8 +123,19 @@ bool SyntheticFileSystem::writeInode(InodeIdentifier, const ByteBuffer&)
     return false;
 }
 
-ssize_t SyntheticFileSystem::readInodeBytes(InodeIdentifier, Unix::off_t offset, size_t count, byte* buffer) const
+ssize_t SyntheticFileSystem::readInodeBytes(InodeIdentifier inode, Unix::off_t offset, Unix::size_t count, byte* buffer) const
 {
-    printf("FIXME: Implement SyntheticFileSystem::readInodeBytes().\n");
-    return 0;
+    ASSERT(inode.fileSystemID() == id());
+#ifdef SYNTHFS_DEBUG
+    printf("[synthfs] readInode %u\n", inode.index());
+#endif
+    ASSERT(inode.index() != 1);
+    ASSERT(inode.index() <= m_files.size());
+    ASSERT(offset >= 0);
+    ASSERT(buffer);
+
+    auto& file = *m_files[inode.index() - 1];
+    Unix::ssize_t nread = min(file.data.size() - offset, static_cast<Unix::off_t>(count));
+    memcpy(buffer, file.data.pointer() + offset, nread);
+    return nread;
 }