[feature] update proof-of-work to allow setting required rounds (#4186)

# Description

This updates our proof-of-work middleware, NoLLaMas, to work on a more easily configurable algorithm (thank you f0x for bringing this to my attention!). Instead of requiring that a solution with pre-determined number of '0' chars be found, it now pre-computes a result with a pre-determined nonce value that it expects the client to iterate up-to. (though with some level of jitter applied, to prevent it being too-easily gamed). This allows the user to configure roughly how many hash-encode rounds they want their clients to have to complete.

## Checklist

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [x] I/we have commented the added code, particularly in hard-to-understand areas.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4186
Co-authored-by: kim <grufwub@gmail.com>
Co-committed-by: kim <grufwub@gmail.com>

1 files changed, 117 insertions, 0 deletions

diff --git a/vendor/codeberg.org/gruf/go-bitutil/flag.tpl b/vendor/codeberg.org/gruf/go-bitutil/flag.tpl
new file mode 100644
index 000000000..ac00bfa97
--- /dev/null
+++ b/vendor/codeberg.org/gruf/go-bitutil/flag.tpl
@@ -0,0 +1,117 @@
+package bitutil
+
+import (
+    "strings"
+    "unsafe"
+)
+
+{{ range $idx, $size := . }}
+
+// Flags{{ $size.Size }} is a type-casted unsigned integer with helper
+// methods for easily managing up to {{ $size.Size }} bit-flags.
+type Flags{{ $size.Size }} uint{{ $size.Size }}
+
+// Get will fetch the flag bit value at index 'bit'.
+func (f Flags{{ $size.Size }}) Get(bit uint8) bool {
+    mask := Flags{{ $size.Size }}(1) << bit
+    return (f & mask != 0)
+}
+
+// Set will set the flag bit value at index 'bit'.
+func (f Flags{{ $size.Size }}) Set(bit uint8) Flags{{ $size.Size }} {
+    mask := Flags{{ $size.Size }}(1) << bit
+    return f | mask
+}
+
+// Unset will unset the flag bit value at index 'bit'.
+func (f Flags{{ $size.Size }}) Unset(bit uint8) Flags{{ $size.Size }} {
+    mask := Flags{{ $size.Size }}(1) << bit
+    return f & ^mask
+}
+
+{{ range $idx := $size.Bits }}
+
+// Get{{ $idx }} will fetch the flag bit value at index {{ $idx }}.
+func (f Flags{{ $size.Size }}) Get{{ $idx }}() bool {
+    const mask = Flags{{ $size.Size }}(1) << {{ $idx }}
+    return (f & mask != 0)
+}
+
+// Set{{ $idx }} will set the flag bit value at index {{ $idx }}.
+func (f Flags{{ $size.Size }}) Set{{ $idx }}() Flags{{ $size.Size }} {
+    const mask = Flags{{ $size.Size }}(1) << {{ $idx }}
+    return f | mask
+}
+
+// Unset{{ $idx }} will unset the flag bit value at index {{ $idx }}.
+func (f Flags{{ $size.Size }}) Unset{{ $idx }}() Flags{{ $size.Size }} {
+    const mask = Flags{{ $size.Size }}(1) << {{ $idx }}
+    return f & ^mask
+}
+
+{{ end }}
+
+// String returns a human readable representation of Flags{{ $size.Size }}.
+func (f Flags{{ $size.Size }}) String() string {
+    var (
+        i   int
+        val bool
+        buf []byte
+    )
+
+    // Make a prealloc est. based on longest-possible value
+    const prealloc = 1+(len("false ")*{{ $size.Size }})-1+1
+    buf = make([]byte, prealloc)
+
+    buf[i] = '{'
+    i++
+
+    {{ range $idx := .Bits }}
+    val = f.Get{{ $idx }}()
+    i += copy(buf[i:], bool2str(val))
+    buf[i] = ' '
+    i++
+    {{ end }}
+
+    buf[i-1] = '}'
+    buf = buf[:i]
+
+    return *(*string)(unsafe.Pointer(&buf))
+}
+
+// GoString returns a more verbose human readable representation of Flags{{ $size.Size }}.
+func (f Flags{{ $size.Size }})GoString() string {
+    var (
+        i   int
+        val bool
+        buf []byte
+    )
+
+    // Make a prealloc est. based on longest-possible value
+    const prealloc = len("bitutil.Flags{{ $size.Size }}{")+(len("{{ sub $size.Size 1 }}=false ")*{{ $size.Size }})-1+1
+    buf = make([]byte, prealloc)
+
+    i += copy(buf[i:], "bitutil.Flags{{ $size.Size }}{")
+
+    {{ range $idx := .Bits }}
+    val = f.Get{{ $idx }}()
+    i += copy(buf[i:], "{{ $idx }}=")
+    i += copy(buf[i:], bool2str(val))
+    buf[i] = ' '
+    i++
+    {{ end }}
+ 
+    buf[i-1] = '}'
+    buf = buf[:i]
+
+    return *(*string)(unsafe.Pointer(&buf))
+}
+
+{{ end }}
+
+func bool2str(b bool) string {
+    if b {
+        return "true"
+    }
+    return "false"
+}
\ No newline at end of file