diff --git a/cli/cli.cc b/cli/cli.cc
index 182012144..a01c1407a 100644
--- a/cli/cli.cc
+++ b/cli/cli.cc
@@ -21,12 +21,15 @@
  *****************************************************************************/
 
 #include <array>
-#include <stdio.h> /* fprintf () */
-#include <stdlib.h> /* atoi () */
-#include <string.h> /* memcmp () */
+#include <cstdio> /* fprintf () */
+#include <cstdlib> /* atoi () */
+#include <cstring> /* memcmp () */
 #include <signal.h>
+#include <string>
+#include <string_view>
 
 #include <libtransmission/transmission.h>
+
 #include <libtransmission/error.h>
 #include <libtransmission/file.h>
 #include <libtransmission/tr-getopt.h>
diff --git a/gtk/Application.cc b/gtk/Application.cc
index 79c72a7f6..d8dd070f9 100644
--- a/gtk/Application.cc
+++ b/gtk/Application.cc
@@ -21,17 +21,17 @@
  *****************************************************************************/
 
 #include <algorithm>
-#include <locale.h>
+#include <cstdlib> // exit()
+#include <ctime>
 #include <map>
-#include <signal.h>
 #include <sstream>
-#include <stdio.h>
-#include <stdlib.h> /* exit() */
-#include <string.h>
-#include <thread>
-#include <time.h>
-#include <vector>
+#include <string>
 #include <string_view>
+#include <thread>
+#include <vector>
+
+#include <locale.h>
+#include <signal.h>
 
 #include <giomm.h>
 #include <glib/gmessages.h>
diff --git a/gtk/DetailsDialog.cc b/gtk/DetailsDialog.cc
index 2ddd85cd4..5df15f73c 100644
--- a/gtk/DetailsDialog.cc
+++ b/gtk/DetailsDialog.cc
@@ -13,6 +13,7 @@
 #include <stddef.h>
 #include <stdio.h> /* sscanf() */
 #include <stdlib.h> /* abort() */
+#include <string>
 #include <string_view>
 #include <unordered_map>
 
diff --git a/gtk/Dialogs.cc b/gtk/Dialogs.cc
index ea1bb2e7b..b06e96a95 100644
--- a/gtk/Dialogs.cc
+++ b/gtk/Dialogs.cc
@@ -21,6 +21,7 @@
  *****************************************************************************/
 
 #include <algorithm>
+#include <memory>
 
 #include <glibmm.h>
 #include <glibmm/i18n.h>
diff --git a/gtk/FaviconCache.cc b/gtk/FaviconCache.cc
index a3c842073..d5f90a8c4 100644
--- a/gtk/FaviconCache.cc
+++ b/gtk/FaviconCache.cc
@@ -7,6 +7,8 @@
  */
 
 #include <array>
+#include <memory>
+#include <string>
 
 #include <glib/gstdio.h> /* g_remove() */
 
diff --git a/gtk/FileList.cc b/gtk/FileList.cc
index dad5a9612..9a5e7b530 100644
--- a/gtk/FileList.cc
+++ b/gtk/FileList.cc
@@ -6,11 +6,10 @@
  *
  */
 
+#include <climits> /* INT_MAX */
+#include <cstddef>
 #include <cstring> // strchr
-#include <limits.h> /* INT_MAX */
-#include <stddef.h>
-#include <stdio.h>
-#include <string.h>
+#include <string>
 
 #include <glibmm.h>
 #include <glibmm/i18n.h>
diff --git a/gtk/FilterBar.cc b/gtk/FilterBar.cc
index 6bfab8042..82fd03109 100644
--- a/gtk/FilterBar.cc
+++ b/gtk/FilterBar.cc
@@ -6,8 +6,9 @@
  *
  */
 
+#include <memory>
 #include <set>
-#include <stdlib.h> /* qsort() */
+#include <string>
 #include <unordered_map>
 
 #include <glibmm.h>
diff --git a/gtk/FreeSpaceLabel.cc b/gtk/FreeSpaceLabel.cc
index 1eb577e6b..e1cb09cbd 100644
--- a/gtk/FreeSpaceLabel.cc
+++ b/gtk/FreeSpaceLabel.cc
@@ -6,6 +6,9 @@
  *
  */
 
+#include <memory>
+#include <string>
+
 #include <glibmm/i18n.h>
 
 #include <libtransmission/utils.h>
diff --git a/gtk/IconCache.cc b/gtk/IconCache.cc
index f8223c08e..e868bd458 100644
--- a/gtk/IconCache.cc
+++ b/gtk/IconCache.cc
@@ -6,6 +6,7 @@
  */
 
 #include <array>
+#include <memory>
 #include <unordered_map>
 
 #include <glibmm.h>
diff --git a/gtk/MainWindow.cc b/gtk/MainWindow.cc
index 8642eaec2..9879b00de 100644
--- a/gtk/MainWindow.cc
+++ b/gtk/MainWindow.cc
@@ -20,6 +20,8 @@
  * DEALINGS IN THE SOFTWARE.
  *****************************************************************************/
 
+#include <string>
+
 #include <glibmm/i18n.h>
 
 #include <libtransmission/transmission.h>
diff --git a/gtk/MakeDialog.cc b/gtk/MakeDialog.cc
index 922ac46dd..02e97d9d2 100644
--- a/gtk/MakeDialog.cc
+++ b/gtk/MakeDialog.cc
@@ -6,6 +6,9 @@
  *
  */
 
+#include <memory>
+#include <string>
+
 #include <glibmm.h>
 #include <glibmm/i18n.h>
 
diff --git a/gtk/MessageLogWindow.cc b/gtk/MessageLogWindow.cc
index 84e38b9b4..017b01654 100644
--- a/gtk/MessageLogWindow.cc
+++ b/gtk/MessageLogWindow.cc
@@ -8,7 +8,6 @@
 
 #include <errno.h>
 #include <stdio.h>
-#include <string.h>
 
 #include <glibmm.h>
 #include <glibmm/i18n.h>
diff --git a/gtk/OptionsDialog.cc b/gtk/OptionsDialog.cc
index c8d747c4c..af6355d1d 100644
--- a/gtk/OptionsDialog.cc
+++ b/gtk/OptionsDialog.cc
@@ -6,8 +6,7 @@
  *
  */
 
-#include <cctype>
-#include <string.h>
+#include <memory>
 
 #include <glibmm.h>
 #include <glibmm/i18n.h>
diff --git a/gtk/Prefs.cc b/gtk/Prefs.cc
index 3f2e894e6..15648d220 100644
--- a/gtk/Prefs.cc
+++ b/gtk/Prefs.cc
@@ -21,9 +21,7 @@
  *****************************************************************************/
 
 #include <errno.h>
-#include <stdio.h>
 #include <stdlib.h> /* strtol() */
-#include <string.h>
 #include <string_view>
 
 #include <unistd.h>
diff --git a/gtk/PrefsDialog.cc b/gtk/PrefsDialog.cc
index 0661d2c49..b5a377509 100644
--- a/gtk/PrefsDialog.cc
+++ b/gtk/PrefsDialog.cc
@@ -6,9 +6,9 @@
  *
  */
 
-#include <ctype.h> /* isspace */
-#include <limits.h> /* USHRT_MAX, INT_MAX */
+#include <climits> /* USHRT_MAX, INT_MAX */
 #include <sstream>
+#include <string>
 #include <unistd.h>
 
 #include <glibmm.h>
diff --git a/gtk/RelocateDialog.cc b/gtk/RelocateDialog.cc
index ca396551c..c3fefa586 100644
--- a/gtk/RelocateDialog.cc
+++ b/gtk/RelocateDialog.cc
@@ -7,6 +7,8 @@
  */
 
 #include <algorithm>
+#include <memory>
+#include <string>
 
 #include <glibmm.h>
 #include <glibmm/i18n.h>
diff --git a/gtk/Session.cc b/gtk/Session.cc
index 0a7d95a9e..fd63a9e09 100644
--- a/gtk/Session.cc
+++ b/gtk/Session.cc
@@ -21,10 +21,12 @@
  *****************************************************************************/
 
 #include <algorithm>
+#include <cmath> /* pow() */
 #include <cstring> // strstr
 #include <functional>
 #include <map>
-#include <math.h> /* pow() */
+#include <memory>
+#include <string>
 
 #include <glibmm/i18n.h>
 
diff --git a/gtk/Session.h b/gtk/Session.h
index a1f4d8eec..97af9e913 100644
--- a/gtk/Session.h
+++ b/gtk/Session.h
@@ -23,6 +23,7 @@
 #pragma once
 
 #include <memory>
+#include <string>
 #include <vector>
 
 #include <giomm.h>
diff --git a/gtk/StatsDialog.cc b/gtk/StatsDialog.cc
index d227e5bf9..3c0c6f0c0 100644
--- a/gtk/StatsDialog.cc
+++ b/gtk/StatsDialog.cc
@@ -6,6 +6,8 @@
  *
  */
 
+#include <memory>
+
 #include <glibmm.h>
 #include <glibmm/i18n.h>
 
diff --git a/gtk/TorrentCellRenderer.cc b/gtk/TorrentCellRenderer.cc
index fd3152c59..5fcf858cd 100644
--- a/gtk/TorrentCellRenderer.cc
+++ b/gtk/TorrentCellRenderer.cc
@@ -6,8 +6,9 @@
  *
  */
 
-#include <limits.h> /* INT_MAX */
+#include <climits> /* INT_MAX */
 #include <cstring> // strchr()
+#include <memory>
 
 #include <glibmm.h>
 #include <glibmm/i18n.h>
diff --git a/gtk/Utils.h b/gtk/Utils.h
index 45041073e..19b50509c 100644
--- a/gtk/Utils.h
+++ b/gtk/Utils.h
@@ -8,6 +8,7 @@
 
 #pragma once
 
+#include <ctime>
 #include <functional>
 #include <string>
 
diff --git a/gtk/main.cc b/gtk/main.cc
index 510864ece..e3663b841 100644
--- a/gtk/main.cc
+++ b/gtk/main.cc
@@ -20,6 +20,7 @@
  * DEALINGS IN THE SOFTWARE.
  *****************************************************************************/
 
+#include <cstdio>
 #include <string>
 
 #include <glibmm.h>
diff --git a/libtransmission/announce-list.cc b/libtransmission/announce-list.cc
index a51a82e86..27a03b66d 100644
--- a/libtransmission/announce-list.cc
+++ b/libtransmission/announce-list.cc
@@ -15,6 +15,7 @@
 
 #include "announce-list.h"
 #include "metainfo.h"
+#include "quark.h"
 #include "utils.h"
 #include "variant.h"
 
diff --git a/libtransmission/announce-list.h b/libtransmission/announce-list.h
index 33a4f789a..5c4ccd86f 100644
--- a/libtransmission/announce-list.h
+++ b/libtransmission/announce-list.h
@@ -17,12 +17,12 @@
 #include <cstddef>
 #include <optional>
 #include <set>
-#include <string>
 #include <string_view>
 #include <vector>
 
 #include "transmission.h"
 
+#include "quark.h"
 #include "interned-string.h"
 #include "web-utils.h"
 
diff --git a/libtransmission/announcer-common.h b/libtransmission/announcer-common.h
index 72cb9ecab..1677bac17 100644
--- a/libtransmission/announcer-common.h
+++ b/libtransmission/announcer-common.h
@@ -15,7 +15,6 @@
 #include <array>
 #include <cstddef> // size_t
 #include <string>
-#include <string_view>
 
 #include "transmission.h"
 
diff --git a/libtransmission/announcer-http.cc b/libtransmission/announcer-http.cc
index 9d1a729ab..246c0dd36 100644
--- a/libtransmission/announcer-http.cc
+++ b/libtransmission/announcer-http.cc
@@ -9,6 +9,7 @@
 #include <climits> /* USHRT_MAX */
 #include <cstdio> /* fprintf() */
 #include <cstring> /* strchr(), memcmp(), memcpy() */
+#include <string>
 #include <string_view>
 
 #include <event2/buffer.h>
@@ -21,6 +22,7 @@
 #include "log.h"
 #include "net.h" /* tr_globalIPv6() */
 #include "peer-mgr.h" /* pex */
+#include "quark.h"
 #include "torrent.h"
 #include "trevent.h" /* tr_runInEventThread() */
 #include "utils.h"
diff --git a/libtransmission/announcer-udp.cc b/libtransmission/announcer-udp.cc
index 7964cc8dd..04cd444b5 100644
--- a/libtransmission/announcer-udp.cc
+++ b/libtransmission/announcer-udp.cc
@@ -9,6 +9,7 @@
 #include <cerrno> /* errno, EAFNOSUPPORT */
 #include <cstring> /* memset() */
 #include <ctime>
+#include <string_view>
 #include <vector>
 
 #include <event2/buffer.h>
diff --git a/libtransmission/announcer.cc b/libtransmission/announcer.cc
index fd19654a7..72e15f839 100644
--- a/libtransmission/announcer.cc
+++ b/libtransmission/announcer.cc
@@ -14,6 +14,7 @@
 #include <ctime>
 #include <map>
 #include <set>
+#include <string>
 #include <string_view>
 #include <vector>
 
diff --git a/libtransmission/announcer.h b/libtransmission/announcer.h
index c35ac7b0c..db301bd35 100644
--- a/libtransmission/announcer.h
+++ b/libtransmission/announcer.h
@@ -13,6 +13,8 @@
 #endif
 
 #include <cstddef> // size_t
+#include <ctime>
+#include <string_view>
 
 #include "transmission.h"
 
diff --git a/libtransmission/bitfield.h b/libtransmission/bitfield.h
index d78fd3d24..33deec797 100644
--- a/libtransmission/bitfield.h
+++ b/libtransmission/bitfield.h
@@ -13,7 +13,6 @@
 #endif
 
 #include <cstddef>
-#include <cstdint>
 #include <vector>
 
 /**
diff --git a/libtransmission/crypto-utils-fallback.cc b/libtransmission/crypto-utils-fallback.cc
index f25a639ae..d8e114ccc 100644
--- a/libtransmission/crypto-utils-fallback.cc
+++ b/libtransmission/crypto-utils-fallback.cc
@@ -10,7 +10,10 @@
    implement missing (or duplicate) functionality without exposing internal
    details in header files. */
 
+#include <string_view>
+
 #include "transmission.h"
+
 #include "crypto-utils.h"
 #include "tr-assert.h"
 #include "tr-macros.h"
diff --git a/libtransmission/crypto-utils.cc b/libtransmission/crypto-utils.cc
index cc80e4ae2..0661e019e 100644
--- a/libtransmission/crypto-utils.cc
+++ b/libtransmission/crypto-utils.cc
@@ -8,6 +8,7 @@
 
 #include <algorithm>
 #include <array>
+#include <cctype>
 #include <cstring> // memmove(), memset()
 #include <iterator>
 #include <random>
diff --git a/libtransmission/crypto.h b/libtransmission/crypto.h
index d29dafae1..6885c03ce 100644
--- a/libtransmission/crypto.h
+++ b/libtransmission/crypto.h
@@ -14,7 +14,6 @@
 #error only libtransmission should #include this header.
 #endif
 
-#include <array>
 #include <cinttypes> // uintX_t
 #include <cstddef>
 #include <optional>
diff --git a/libtransmission/error.cc b/libtransmission/error.cc
index eec8282d7..d22ecec48 100644
--- a/libtransmission/error.cc
+++ b/libtransmission/error.cc
@@ -6,6 +6,8 @@
  *
  */
 
+#include <string_view>
+
 #include "transmission.h"
 
 #include "error.h"
diff --git a/libtransmission/fdlimit.cc b/libtransmission/fdlimit.cc
index 7fc52714c..1dea2dfb5 100644
--- a/libtransmission/fdlimit.cc
+++ b/libtransmission/fdlimit.cc
@@ -10,7 +10,6 @@
 #include <array>
 #include <cerrno>
 #include <cinttypes>
-#include <cstring>
 #include <ctime>
 
 #include "transmission.h"
diff --git a/libtransmission/file-posix.cc b/libtransmission/file-posix.cc
index e5e6c7f4b..e71ebbc90 100644
--- a/libtransmission/file-posix.cc
+++ b/libtransmission/file-posix.cc
@@ -20,12 +20,14 @@
 #include <dirent.h>
 #include <fcntl.h> /* O_LARGEFILE, posix_fadvise(), [posix_]fallocate(), fcntl() */
 #include <libgen.h> /* basename(), dirname() */
+#include <string_view>
+#include <unistd.h> /* lseek(), write(), ftruncate(), pread(), pwrite(), pathconf(), etc */
+#include <vector>
+
 #include <sys/file.h> /* flock() */
 #include <sys/mman.h> /* mmap(), munmap() */
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <unistd.h> /* lseek(), write(), ftruncate(), pread(), pwrite(), pathconf(), etc */
-#include <vector>
 
 #ifdef HAVE_XFS_XFS_H
 #include <xfs/xfs.h>
diff --git a/libtransmission/file.cc b/libtransmission/file.cc
index ef839ccaf..96466d7ed 100644
--- a/libtransmission/file.cc
+++ b/libtransmission/file.cc
@@ -7,7 +7,7 @@
  */
 
 #include <algorithm>
-#include <cstring> /* strlen() */
+#include <string_view>
 
 #include "transmission.h"
 #include "error.h"
diff --git a/libtransmission/inout.cc b/libtransmission/inout.cc
index c060f8d16..a0cab34b5 100644
--- a/libtransmission/inout.cc
+++ b/libtransmission/inout.cc
@@ -8,7 +8,7 @@
 
 #include <algorithm>
 #include <cerrno>
-#include <cstdlib> /* bsearch() */
+#include <cstdlib> /* abort() */
 #include <optional>
 #include <vector>
 
diff --git a/libtransmission/metainfo.cc b/libtransmission/metainfo.cc
index 16ee014fc..a5b3f063c 100644
--- a/libtransmission/metainfo.cc
+++ b/libtransmission/metainfo.cc
@@ -8,8 +8,10 @@
 
 #include <algorithm>
 #include <array>
-#include <cstring>
+#include <cctype>
 #include <iterator>
+#include <memory>
+#include <string>
 #include <string_view>
 #include <vector>
 
diff --git a/libtransmission/metainfo.h b/libtransmission/metainfo.h
index c55532732..1352ec710 100644
--- a/libtransmission/metainfo.h
+++ b/libtransmission/metainfo.h
@@ -12,7 +12,6 @@
 #error only libtransmission should #include this header.
 #endif
 
-#include <algorithm>
 #include <cstdint>
 #include <optional>
 #include <string>
diff --git a/libtransmission/peer-io.cc b/libtransmission/peer-io.cc
index 128d5ce02..805152757 100644
--- a/libtransmission/peer-io.cc
+++ b/libtransmission/peer-io.cc
@@ -10,6 +10,7 @@
 #include <cerrno>
 #include <cstdint>
 #include <cstring>
+#include <string>
 
 #include <event2/event.h>
 #include <event2/buffer.h>
diff --git a/libtransmission/peer-mgr.h b/libtransmission/peer-mgr.h
index e79f56bb7..3f0ac9644 100644
--- a/libtransmission/peer-mgr.h
+++ b/libtransmission/peer-mgr.h
@@ -13,7 +13,7 @@
 #endif
 
 #include <cinttypes> // uintX_t
-#include <cstdlib> // size_t
+#include <cstddef> // size_t
 #include <vector>
 
 #ifdef _WIN32
@@ -23,7 +23,6 @@
 #include "net.h" /* tr_address */
 #include "peer-common.h"
 #include "peer-socket.h"
-#include "quark.h"
 
 /**
  * @addtogroup peers Peers
diff --git a/libtransmission/peer-msgs.cc b/libtransmission/peer-msgs.cc
index 565db9e0b..85e122528 100644
--- a/libtransmission/peer-msgs.cc
+++ b/libtransmission/peer-msgs.cc
@@ -9,7 +9,6 @@
 #include <algorithm>
 #include <cerrno>
 #include <cstdarg>
-#include <cstdlib>
 #include <cstring>
 #include <ctime>
 #include <memory> // std::unique_ptr
@@ -29,6 +28,7 @@
 #include "peer-mgr.h"
 #include "peer-msgs.h"
 #include "ptrarray.h"
+#include "quark.h"
 #include "session.h"
 #include "torrent-magnet.h"
 #include "torrent.h"
diff --git a/libtransmission/platform-quota.cc b/libtransmission/platform-quota.cc
index 80e65c852..27f51a0cd 100644
--- a/libtransmission/platform-quota.cc
+++ b/libtransmission/platform-quota.cc
@@ -8,6 +8,7 @@
 
 #include <cerrno>
 #include <cstring>
+#include <string>
 #include <string_view>
 
 #include <event2/util.h> /* evutil_ascii_strcasecmp() */
diff --git a/libtransmission/platform-quota.h b/libtransmission/platform-quota.h
index 710ba5f57..55dd3e227 100644
--- a/libtransmission/platform-quota.h
+++ b/libtransmission/platform-quota.h
@@ -8,7 +8,7 @@
 
 #pragma once
 
-#include <cstdint>
+#include <cstdint> // int64_t
 #include <string>
 #include <string_view>
 
diff --git a/libtransmission/platform.cc b/libtransmission/platform.cc
index 5bafcca6c..b9d7fb72c 100644
--- a/libtransmission/platform.cc
+++ b/libtransmission/platform.cc
@@ -8,7 +8,6 @@
 
 #include <algorithm>
 #include <cstdarg>
-#include <cstdlib>
 #include <cstring>
 #include <list>
 #include <string>
diff --git a/libtransmission/port-forwarding.cc b/libtransmission/port-forwarding.cc
index c6354c097..898857776 100644
--- a/libtransmission/port-forwarding.cc
+++ b/libtransmission/port-forwarding.cc
@@ -7,7 +7,6 @@
  */
 
 #include <algorithm>
-#include <cstdio>
 #include <sys/types.h>
 
 #include <event2/event.h>
diff --git a/libtransmission/quark.cc b/libtransmission/quark.cc
index 933052bab..723815a74 100644
--- a/libtransmission/quark.cc
+++ b/libtransmission/quark.cc
@@ -12,8 +12,8 @@
 #include <vector>
 
 #include "transmission.h"
+
 #include "quark.h"
-#include "tr-assert.h"
 #include "utils.h" // tr_strvDup()
 
 using namespace std::literals;
diff --git a/libtransmission/rpc-server.cc b/libtransmission/rpc-server.cc
index 78ff5ed33..cc874dcfc 100644
--- a/libtransmission/rpc-server.cc
+++ b/libtransmission/rpc-server.cc
@@ -31,6 +31,7 @@
 #include "log.h"
 #include "net.h"
 #include "platform.h" /* tr_getWebClientDir() */
+#include "quark.h"
 #include "rpc-server.h"
 #include "rpcimpl.h"
 #include "session-id.h"
diff --git a/libtransmission/rpcimpl.cc b/libtransmission/rpcimpl.cc
index 1edd31656..0e535bf9b 100644
--- a/libtransmission/rpcimpl.cc
+++ b/libtransmission/rpcimpl.cc
@@ -21,6 +21,7 @@
 #include <zlib.h>
 
 #include "transmission.h"
+
 #include "completion.h"
 #include "crypto-utils.h"
 #include "error.h"
@@ -28,9 +29,10 @@
 #include "file.h"
 #include "log.h"
 #include "platform-quota.h" /* tr_device_info_get_disk_space() */
+#include "quark.h"
 #include "rpcimpl.h"
-#include "session.h"
 #include "session-id.h"
+#include "session.h"
 #include "stats.h"
 #include "torrent.h"
 #include "tr-assert.h"
@@ -38,8 +40,8 @@
 #include "utils.h"
 #include "variant.h"
 #include "version.h"
-#include "web.h"
 #include "web-utils.h"
+#include "web.h"
 
 static auto constexpr RpcVersion = int64_t{ 17 };
 static auto constexpr RpcVersionMin = int64_t{ 14 };
diff --git a/libtransmission/session.cc b/libtransmission/session.cc
index 2d4bb71d1..a4e0e70ef 100644
--- a/libtransmission/session.cc
+++ b/libtransmission/session.cc
@@ -15,6 +15,7 @@
 #include <ctime>
 #include <iterator> // std::back_inserter
 #include <list>
+#include <memory>
 #include <numeric> // std::acumulate()
 #include <string_view>
 #include <unordered_set>
@@ -2841,3 +2842,9 @@ void tr_sessionRemoveTorrent(tr_session* session, tr_torrent* tor)
     session->torrentsById.erase(tor->uniqueId);
     session->torrentsByHash.erase(tor->infoHash());
 }
+
+tr_torrent* tr_session::getTorrent(std::string_view info_dict_hash_string)
+{
+    auto info_dict_hash = tr_sha1_from_string(std::data(info_dict_hash_string));
+    return this->getTorrent(info_dict_hash);
+}
diff --git a/libtransmission/session.h b/libtransmission/session.h
index 878187f01..e22d5d31d 100644
--- a/libtransmission/session.h
+++ b/libtransmission/session.h
@@ -29,9 +29,7 @@
 
 #include "transmission.h"
 
-#include "crypto-utils.h"
-#include "net.h"
-#include "tr-macros.h"
+#include "net.h" // tr_socket_t
 
 enum tr_auto_switch_state_t
 {
@@ -125,11 +123,7 @@ public:
         return it == std::end(src) ? nullptr : it->second;
     }
 
-    [[nodiscard]] auto getTorrent(std::string_view info_dict_hash_string)
-    {
-        auto info_dict_hash = tr_sha1_from_string(std::data(info_dict_hash_string));
-        return this->getTorrent(info_dict_hash);
-    }
+    [[nodiscard]] tr_torrent* getTorrent(std::string_view info_dict_hash_string);
 
     [[nodiscard]] auto contains(tr_sha1_digest_t const& info_dict_hash) const
     {
diff --git a/libtransmission/stats.cc b/libtransmission/stats.cc
index 7d10d20e3..ea221a894 100644
--- a/libtransmission/stats.cc
+++ b/libtransmission/stats.cc
@@ -7,6 +7,7 @@
  */
 
 #include <ctime>
+#include <string>
 
 #include "transmission.h"
 
diff --git a/libtransmission/subprocess-posix.cc b/libtransmission/subprocess-posix.cc
index 05cf112c5..d18b85cbb 100644
--- a/libtransmission/subprocess-posix.cc
+++ b/libtransmission/subprocess-posix.cc
@@ -8,7 +8,6 @@
 
 #include <cerrno>
 #include <csignal>
-#include <cstdlib>
 #include <map>
 #include <string_view>
 
diff --git a/libtransmission/torrent-ctor.cc b/libtransmission/torrent-ctor.cc
index b8f25f978..21d943e64 100644
--- a/libtransmission/torrent-ctor.cc
+++ b/libtransmission/torrent-ctor.cc
@@ -9,6 +9,7 @@
 #include <cerrno> // EINVAL
 #include <optional>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #include "transmission.h"
diff --git a/libtransmission/torrent-magnet.cc b/libtransmission/torrent-magnet.cc
index bc9b27a73..76b31a81e 100644
--- a/libtransmission/torrent-magnet.cc
+++ b/libtransmission/torrent-magnet.cc
@@ -8,8 +8,8 @@
 
 #include <algorithm>
 #include <climits> /* INT_MAX */
-#include <cstring> /* memcpy(), memset(), memcmp() */
 #include <ctime>
+#include <string>
 #include <string_view>
 
 #include <event2/buffer.h>
diff --git a/libtransmission/torrent-metainfo.cc b/libtransmission/torrent-metainfo.cc
index a0e644e8b..6daa8c89d 100644
--- a/libtransmission/torrent-metainfo.cc
+++ b/libtransmission/torrent-metainfo.cc
@@ -7,6 +7,7 @@
  */
 
 #include <algorithm>
+#include <cctype>
 #include <iterator>
 #include <numeric>
 #include <string>
@@ -20,8 +21,8 @@
 #include "crypto-utils.h"
 #include "error-types.h"
 #include "error.h"
+#include "quark.h"
 #include "torrent-metainfo.h"
-#include "tr-assert.h"
 #include "utils.h"
 #include "variant.h"
 #include "web-utils.h"
diff --git a/libtransmission/torrent-metainfo.h b/libtransmission/torrent-metainfo.h
index b865198f5..3af3fe16d 100644
--- a/libtransmission/torrent-metainfo.h
+++ b/libtransmission/torrent-metainfo.h
@@ -17,7 +17,6 @@
 
 #include "block-info.h"
 #include "magnet-metainfo.h"
-#include "quark.h"
 
 struct tr_error;
 struct tr_info;
diff --git a/libtransmission/torrent.cc b/libtransmission/torrent.cc
index 9265055d2..3ed355f93 100644
--- a/libtransmission/torrent.cc
+++ b/libtransmission/torrent.cc
@@ -12,7 +12,6 @@
 #include <climits> /* INT_MAX */
 #include <cmath>
 #include <csignal> /* signal() */
-#include <cstdlib> /* qsort */
 #include <cstring> /* memcmp */
 #include <ctime>
 #include <map>
diff --git a/libtransmission/torrent.h b/libtransmission/torrent.h
index 9cc7b6e4f..b2281d5c4 100644
--- a/libtransmission/torrent.h
+++ b/libtransmission/torrent.h
@@ -30,7 +30,6 @@
 #include "file.h"
 #include "file-piece-map.h"
 #include "interned-string.h"
-#include "quark.h"
 #include "session.h"
 #include "tr-assert.h"
 #include "tr-macros.h"
diff --git a/libtransmission/tr-getopt.cc b/libtransmission/tr-getopt.cc
index 94a1d7c35..6f92d992f 100644
--- a/libtransmission/tr-getopt.cc
+++ b/libtransmission/tr-getopt.cc
@@ -7,8 +7,6 @@
  */
 
 #include <algorithm>
-#include <cctype> /* isspace() */
-#include <cstdio>
 #include <cstdlib> /* exit() */
 #include <cstring>
 #include <string_view>
diff --git a/libtransmission/tr-lpd.cc b/libtransmission/tr-lpd.cc
index cde05f2c0..de29f33ca 100644
--- a/libtransmission/tr-lpd.cc
+++ b/libtransmission/tr-lpd.cc
@@ -21,10 +21,8 @@ THE SOFTWARE.
 */
 
 #include <algorithm>
-#include <cctype> /* toupper() */
 #include <cerrno>
 #include <csignal> /* sig_atomic_t */
-#include <cstdio>
 #include <cstring> /* strlen(), strncpy(), strstr(), memset() */
 #include <type_traits>
 
diff --git a/libtransmission/utils.cc b/libtransmission/utils.cc
index 524c2d609..79b4544b0 100644
--- a/libtransmission/utils.cc
+++ b/libtransmission/utils.cc
@@ -20,7 +20,6 @@
 #include <clocale> /* localeconv() */
 #include <cmath> /* fabs(), floor() */
 #include <cstdint> /* SIZE_MAX */
-#include <cstdio>
 #include <cstdlib> /* getenv() */
 #include <cstring> /* strerror(), memset(), memmem() */
 #include <ctime> /* nanosleep() */
@@ -29,6 +28,7 @@
 #include <set>
 #include <sstream>
 #include <string>
+#include <string_view>
 #include <vector>
 
 #ifdef _WIN32
diff --git a/libtransmission/variant-benc.cc b/libtransmission/variant-benc.cc
index 88da7f11a..1973e0dc7 100644
--- a/libtransmission/variant-benc.cc
+++ b/libtransmission/variant-benc.cc
@@ -7,7 +7,6 @@
  */
 
 #include <array>
-#include <cstdlib>
 #include <cctype> /* isdigit() */
 #include <deque>
 #include <cerrno>
@@ -21,6 +20,7 @@
 #include "transmission.h"
 
 #include "tr-assert.h"
+#include "quark.h"
 #include "utils.h" /* tr_snprintf() */
 #include "variant-common.h"
 #include "variant.h"
diff --git a/libtransmission/variant-json.cc b/libtransmission/variant-json.cc
index b6553317c..96dc65142 100644
--- a/libtransmission/variant-json.cc
+++ b/libtransmission/variant-json.cc
@@ -10,7 +10,6 @@
 #include <cctype>
 #include <cerrno> /* EILSEQ, EINVAL */
 #include <cmath> /* fabs() */
-#include <cstdio>
 #include <cstring>
 #include <deque>
 #include <string_view>
@@ -24,6 +23,7 @@
 
 #include "jsonsl.h"
 #include "log.h"
+#include "quark.h"
 #include "tr-assert.h"
 #include "utils.h"
 #include "variant-common.h"
diff --git a/libtransmission/variant.cc b/libtransmission/variant.cc
index 7478fb6f1..1baead23c 100644
--- a/libtransmission/variant.cc
+++ b/libtransmission/variant.cc
@@ -20,6 +20,7 @@
 #include <cstdlib> /* strtod() */
 #include <cstring>
 #include <stack>
+#include <string>
 #include <string_view>
 #include <vector>
 
@@ -38,13 +39,15 @@
 #define LIBTRANSMISSION_VARIANT_MODULE
 
 #include "transmission.h"
+
 #include "error.h"
 #include "file.h"
 #include "log.h"
+#include "quark.h"
 #include "tr-assert.h"
 #include "utils.h"
-#include "variant.h"
 #include "variant-common.h"
+#include "variant.h"
 
 /* don't use newlocale/uselocale on old versions of uClibc because they're buggy.
  * https://trac.transmissionbt.com/ticket/6006 */
diff --git a/libtransmission/variant.h b/libtransmission/variant.h
index d615e4ba0..64ad34597 100644
--- a/libtransmission/variant.h
+++ b/libtransmission/variant.h
@@ -8,8 +8,9 @@
 
 #pragma once
 
+#include <cinttypes> // int64_t
 #include <cstddef> // size_t
-#include <inttypes.h> // int64_t
+#include <string>
 #include <string_view>
 
 #include "quark.h"
diff --git a/libtransmission/watchdir-inotify.cc b/libtransmission/watchdir-inotify.cc
index 0de80256a..a0158dcb4 100644
--- a/libtransmission/watchdir-inotify.cc
+++ b/libtransmission/watchdir-inotify.cc
@@ -8,7 +8,6 @@
 
 #include <cerrno>
 #include <climits> /* NAME_MAX */
-#include <cstdlib> /* realloc() */
 
 #include <unistd.h> /* close() */
 
diff --git a/libtransmission/watchdir.cc b/libtransmission/watchdir.cc
index 1821f1d44..dbada83f4 100644
--- a/libtransmission/watchdir.cc
+++ b/libtransmission/watchdir.cc
@@ -7,6 +7,7 @@
  */
 
 #include <cstring> /* strcmp() */
+#include <string>
 #include <string_view>
 #include <unordered_set>
 
diff --git a/libtransmission/web-utils.cc b/libtransmission/web-utils.cc
index 0e6b16ba5..46c6291ee 100644
--- a/libtransmission/web-utils.cc
+++ b/libtransmission/web-utils.cc
@@ -10,8 +10,10 @@
 #include <array>
 #include <cctype>
 #include <cstddef>
+#include <cstdlib>
 #include <limits>
 #include <optional>
+#include <string>
 #include <string_view>
 
 #include <event2/buffer.h>
diff --git a/libtransmission/web-utils.h b/libtransmission/web-utils.h
index 5d0a2d86b..2ecd34e0b 100644
--- a/libtransmission/web-utils.h
+++ b/libtransmission/web-utils.h
@@ -9,6 +9,7 @@
 #pragma once
 
 #include <optional>
+#include <string>
 #include <string_view>
 
 #include "tr-macros.h" // tr_sha1_digest_t
diff --git a/libtransmission/web.cc b/libtransmission/web.cc
index 31b56472b..38f5f7251 100644
--- a/libtransmission/web.cc
+++ b/libtransmission/web.cc
@@ -7,7 +7,9 @@
  */
 
 #include <algorithm>
+#include <cstring>
 #include <set>
+#include <string>
 #include <string_view>
 
 #ifdef _WIN32
diff --git a/libtransmission/webseed.cc b/libtransmission/webseed.cc
index 9442c6adc..709e845c6 100644
--- a/libtransmission/webseed.cc
+++ b/libtransmission/webseed.cc
@@ -8,6 +8,7 @@
 
 #include <algorithm>
 #include <set>
+#include <string>
 #include <string_view>
 #include <vector>
 
diff --git a/qt/Application.cc b/qt/Application.cc
index 9bfde4642..d13eef494 100644
--- a/qt/Application.cc
+++ b/qt/Application.cc
@@ -11,6 +11,7 @@
 #include <algorithm>
 #include <array>
 #include <ctime>
+#include <memory>
 
 #include <QIcon>
 #include <QLibraryInfo>
diff --git a/qt/Application.h b/qt/Application.h
index 1d7602821..86f219bf3 100644
--- a/qt/Application.h
+++ b/qt/Application.h
@@ -8,6 +8,7 @@
 
 #pragma once
 
+#include <ctime>
 #include <memory>
 #include <unordered_set>
 
diff --git a/qt/FileTreeModel.cc b/qt/FileTreeModel.cc
index cf8f1aa47..6d735b239 100644
--- a/qt/FileTreeModel.cc
+++ b/qt/FileTreeModel.cc
@@ -8,6 +8,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <memory>
 
 #include <libtransmission/transmission.h> // priorities
 
diff --git a/qt/Filters.h b/qt/Filters.h
index f295969a7..72f21e30d 100644
--- a/qt/Filters.h
+++ b/qt/Filters.h
@@ -8,8 +8,6 @@
 
 #pragma once
 
-#include <array>
-
 #include "Torrent.h"
 
 class FilterMode
diff --git a/qt/MainWindow.cc b/qt/MainWindow.cc
index 807378825..d9ea4a768 100644
--- a/qt/MainWindow.cc
+++ b/qt/MainWindow.cc
@@ -9,6 +9,7 @@
 #include <array>
 #include <cassert>
 #include <functional>
+#include <memory>
 #include <utility>
 
 #include <QCheckBox>
diff --git a/qt/OptionsDialog.h b/qt/OptionsDialog.h
index 3f2953e6f..69f1275c7 100644
--- a/qt/OptionsDialog.h
+++ b/qt/OptionsDialog.h
@@ -14,6 +14,7 @@
 #include <QDir>
 #include <QFile>
 #include <QMap>
+#include <QSet>
 #include <QString>
 #include <QTimer>
 
diff --git a/qt/RpcClient.cc b/qt/RpcClient.cc
index 7a6796453..0b5509ec4 100644
--- a/qt/RpcClient.cc
+++ b/qt/RpcClient.cc
@@ -6,9 +6,9 @@
  *
  */
 
-#include "RpcClient.h"
+#include <string_view>
 
-#include <cstring>
+#include "RpcClient.h"
 
 #include <QApplication>
 #include <QAuthenticator>
diff --git a/qt/Torrent.h b/qt/Torrent.h
index b39dab75a..f6a6461b8 100644
--- a/qt/Torrent.h
+++ b/qt/Torrent.h
@@ -8,7 +8,6 @@
 
 #pragma once
 
-#include <array>
 #include <bitset>
 #include <ctime> // time_t
 #include <vector>
diff --git a/qt/TorrentModel.cc b/qt/TorrentModel.cc
index 8424e57aa..b82207a24 100644
--- a/qt/TorrentModel.cc
+++ b/qt/TorrentModel.cc
@@ -8,6 +8,7 @@
 
 #include <algorithm>
 #include <cassert>
+#include <string_view>
 #include <utility>
 
 #include <libtransmission/transmission.h>
diff --git a/qt/VariantHelpers.h b/qt/VariantHelpers.h
index bad7876e3..b9a738243 100644
--- a/qt/VariantHelpers.h
+++ b/qt/VariantHelpers.h
@@ -8,6 +8,7 @@
 
 #pragma once
 
+#include <ctime>
 #include <optional>
 #include <string_view>
 #include <vector>
diff --git a/qt/WatchDir.cc b/qt/WatchDir.cc
index 405afde84..321be1ca7 100644
--- a/qt/WatchDir.cc
+++ b/qt/WatchDir.cc
@@ -6,6 +6,8 @@
  *
  */
 
+#include <memory>
+
 #include <QDir>
 #include <QFileSystemWatcher>
 #include <QTimer>
diff --git a/tests/libtransmission/blocklist-test.cc b/tests/libtransmission/blocklist-test.cc
index 09dcc1852..44e16af66 100644
--- a/tests/libtransmission/blocklist-test.cc
+++ b/tests/libtransmission/blocklist-test.cc
@@ -6,7 +6,6 @@
  *
  */
 
-#include <cstdio>
 #include <cstring> // strlen()
 // #include <unistd.h> // sync()
 
diff --git a/tests/libtransmission/session-test.cc b/tests/libtransmission/session-test.cc
index cb3d7bd46..b7c46cc81 100644
--- a/tests/libtransmission/session-test.cc
+++ b/tests/libtransmission/session-test.cc
@@ -16,7 +16,6 @@
 
 #include <algorithm>
 #include <array>
-#include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <string>
diff --git a/tests/libtransmission/subprocess-test-program.cc b/tests/libtransmission/subprocess-test-program.cc
index 19f14cf36..6d69fb8e4 100644
--- a/tests/libtransmission/subprocess-test-program.cc
+++ b/tests/libtransmission/subprocess-test-program.cc
@@ -11,7 +11,6 @@
 #include "subprocess.h"
 #include "utils.h"
 
-#include <memory>
 #include <string>
 
 int main(int argc, char** argv)
diff --git a/tests/libtransmission/watchdir-test.cc b/tests/libtransmission/watchdir-test.cc
index 8a0194266..41db5093b 100644
--- a/tests/libtransmission/watchdir-test.cc
+++ b/tests/libtransmission/watchdir-test.cc
@@ -6,7 +6,12 @@
  *
  */
 
+#include <map>
+#include <memory>
+#include <string>
+
 #include "transmission.h"
+
 #include "file.h"
 #include "net.h"
 #include "utils.h"
@@ -16,9 +21,6 @@
 
 #include <event2/event.h>
 
-#include <map>
-#include <string>
-
 /***
 ****
 ***/
diff --git a/utils/edit.cc b/utils/edit.cc
index 95ed58441..b23938a4b 100644
--- a/utils/edit.cc
+++ b/utils/edit.cc
@@ -9,6 +9,8 @@
 #include <array>
 #include <stdio.h> /* fprintf() */
 #include <stdlib.h> /* EXIT_FAILURE */
+#include <string>
+#include <string_view>
 #include <vector>
 
 #include <event2/buffer.h>
diff --git a/utils/remote.cc b/utils/remote.cc
index d3afd7c28..754e97a1c 100644
--- a/utils/remote.cc
+++ b/utils/remote.cc
@@ -7,13 +7,14 @@
  */
 
 #include <array>
-#include <assert.h>
-#include <ctype.h> /* isspace */
-#include <errno.h>
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h> /* strcmp */
+#include <cassert>
+#include <cctype> /* isspace */
+#include <cerrno>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring> /* strcmp */
+#include <string>
 #include <string_view>
 
 #include <event2/buffer.h>
diff --git a/utils/show.cc b/utils/show.cc
index 95bcdc740..ace9dfd1e 100644
--- a/utils/show.cc
+++ b/utils/show.cc
@@ -6,13 +6,12 @@
  *
  */
 
+#include <algorithm>
 #include <array>
 #include <cstdio>
-#include <cstring>
-#include <cstdlib>
 #include <ctime>
+#include <string>
 #include <string_view>
-#include <algorithm>
 
 #include <curl/curl.h>