refactor: Add AutoFile::size

Author: fjahr

src/streams.cpp

@@ -116,3 +116,17 @@ size_t DataStream::GetMemoryUsage() const noexcept
 {
     return sizeof(*this) + memusage::DynamicUsage(vch);
 }
+
+int64_t AutoFile::size()
+{
+    if (IsNull()) {
+        throw std::ios_base::failure("AutoFile::size: file handle is nullptr");
+    }
+    // Temporarily save the current position
+    int64_t current_pos = tell();
+    seek(current_pos, SEEK_END);
+    int64_t file_size = tell();
+    // Restore the original position
+    seek(current_pos, SEEK_SET);
+    return file_size;
+}

src/streams.h

@@ -439,6 +439,9 @@ class AutoFile
     /** Find position within the file. Will throw if unknown. */
     int64_t tell();
 
+    /** Return the size of the file. Will throw if unknown. */
+    int64_t size();
+
     /** Wrapper around FileCommit(). */
     bool Commit();
 

src/test/streams_tests.cpp

@@ -27,6 +27,7 @@ BOOST_AUTO_TEST_CASE(xor_file)
         BOOST_CHECK_EXCEPTION(xor_file << std::byte{}, std::ios_base::failure, HasReason{"AutoFile::write: file handle is nullpt"});
         BOOST_CHECK_EXCEPTION(xor_file >> std::byte{}, std::ios_base::failure, HasReason{"AutoFile::read: file handle is nullpt"});
         BOOST_CHECK_EXCEPTION(xor_file.ignore(1), std::ios_base::failure, HasReason{"AutoFile::ignore: file handle is nullpt"});
+        BOOST_CHECK_EXCEPTION(xor_file.size(), std::ios_base::failure, HasReason{"AutoFile::size: file handle is nullptr"});
     }
     {
 #ifdef __MINGW64__
@@ -37,6 +38,7 @@ BOOST_AUTO_TEST_CASE(xor_file)
 #endif
         AutoFile xor_file{raw_file(mode), xor_pat};
         xor_file << test1 << test2;
+        BOOST_CHECK_EQUAL(xor_file.size(), 14);
     }
     {
         // Read raw from disk
@@ -46,6 +48,7 @@ BOOST_AUTO_TEST_CASE(xor_file)
         BOOST_CHECK_EQUAL(HexStr(raw), "fc01fd03fd04fa");
         // Check that no padding exists
         BOOST_CHECK_EXCEPTION(non_xor_file.ignore(1), std::ios_base::failure, HasReason{"AutoFile::ignore: end of file"});
+        BOOST_CHECK_EQUAL(non_xor_file.size(), 14);
     }
     {
         AutoFile xor_file{raw_file("rb"), xor_pat};
@@ -55,6 +58,7 @@ BOOST_AUTO_TEST_CASE(xor_file)
         BOOST_CHECK_EQUAL(HexStr(read2), HexStr(test2));
         // Check that eof was reached
         BOOST_CHECK_EXCEPTION(xor_file >> std::byte{}, std::ios_base::failure, HasReason{"AutoFile::read: end of file"});
+        BOOST_CHECK_EQUAL(xor_file.size(), 14);
     }
     {
         AutoFile xor_file{raw_file("rb"), xor_pat};
@@ -66,6 +70,7 @@ BOOST_AUTO_TEST_CASE(xor_file)
         // Check that ignore and read fail now
         BOOST_CHECK_EXCEPTION(xor_file.ignore(1), std::ios_base::failure, HasReason{"AutoFile::ignore: end of file"});
         BOOST_CHECK_EXCEPTION(xor_file >> std::byte{}, std::ios_base::failure, HasReason{"AutoFile::read: end of file"});
+        BOOST_CHECK_EQUAL(xor_file.size(), 14);
     }
 }
 

src/util/asmap.cpp

@@ -223,10 +223,8 @@ std::vector<bool> DecodeAsmap(fs::path path)
         return {};
     }
 
-    file.seek(0, SEEK_END);
-    int length = file.tell();
+    int64_t length{file.size()};
     LogInfo("Opened asmap file %s (%d bytes) from disk\n", fs::quoted(fs::PathToString(path)), length);
-    file.seek(0, SEEK_SET);
 
     std::vector<std::byte> buffer(length);
     file.read(buffer);

src/wallet/migrate.cpp

@@ -539,8 +539,7 @@ void BerkeleyRODatabase::Open()
     page_size = outer_meta.pagesize;
 
     // Verify the size of the file is a multiple of the page size
-    db_file.seek(0, SEEK_END);
-    int64_t size = db_file.tell();
+    int64_t size{db_file.size()};
 
     // Since BDB stores everything in a page, the file size should be a multiple of the page size;
     // However, BDB doesn't actually check that this is the case, and enforcing this check results