From 5307b027f616601b3ee3f7effd0897499ef9a47e Mon Sep 17 00:00:00 2001
From: Luke Dashjr <luke-jr+git@utopios.org>
Date: Tue, 26 Jul 2016 04:36:22 +0000
Subject: [PATCH] Implement weightlimit

---
 blkmaker.c         | 18 ++++++++++++++++++
 blkmaker_jansson.c |  9 +++++++++
 blktemplate.h      |  2 ++
 3 files changed, 29 insertions(+)

diff --git a/blkmaker.c b/blkmaker.c
index 315ff7b..97f8e5a 100644
--- a/blkmaker.c
+++ b/blkmaker.c
@@ -224,7 +224,9 @@ uint64_t blkmk_init_generation3(blktemplate_t * const tmpl, const void * const s
 	off += 4;
 	
 	const int16_t sigops_counted = blkmk_count_sigops(script, scriptsz, tmpl->_bip141_sigops);
+	const int64_t gentx_weight = (off * 4) + 2 /* marker & flag */ + 1 /* witness stack count */ + 1 /* stack item size */ + 32 /* stack item: nonce */ ;
 	if (tmpl->txns_datasz + off > tmpl->sizelimit
+	 || (tmpl->txns_weight >= 0 && tmpl->txns_weight + gentx_weight > tmpl->weightlimit)
 	 || (tmpl->txns_sigops >= 0 && tmpl->txns_sigops + sigops_counted > tmpl->sigoplimit)) {
 		free(data);
 		return 0;
@@ -241,6 +243,7 @@ uint64_t blkmk_init_generation3(blktemplate_t * const tmpl, const void * const s
 	txn->data = data;
 	txn->datasz = off;
 	txn->sigops_ = sigops_counted;
+	txn->weight = gentx_weight;
 	
 	if (tmpl->cbtxn)
 	{
@@ -442,6 +445,10 @@ bool _blkmk_append_cb(blktemplate_t * const tmpl, void * const vout, const void
 		return false;
 	}
 	
+	if (tmpl->cbtxn->weight + tmpl->txns_weight + (appendsz * 4) > tmpl->weightlimit) {
+		return false;
+	}
+	
 	const int16_t orig_scriptSig_sigops = blkmk_count_sigops(&in[cbScriptSigLen + 1], in[cbScriptSigLen], tmpl->_bip141_sigops);
 	int cbPostScriptSig = cbScriptSigLen + 1 + in[cbScriptSigLen];
 	if (appended_at_offset)
@@ -504,6 +511,16 @@ ssize_t blkmk_append_coinbase_safe2(blktemplate_t * const tmpl, const void * con
 			availsz = availsz2;
 		}
 	}
+	{
+		const size_t current_blockweight = tmpl->cbtxn->weight + tmpl->txns_weight;
+		if (current_blockweight > tmpl->weightlimit) {
+			return false;
+		}
+		const size_t availsz2 = (tmpl->weightlimit - current_blockweight) / 4;
+		if (availsz2 < availsz) {
+			availsz = availsz2;
+		}
+	}
 	if (appendsz > availsz)
 		return availsz;
 	
@@ -515,6 +532,7 @@ ssize_t blkmk_append_coinbase_safe2(blktemplate_t * const tmpl, const void * con
 	if (!_blkmk_append_cb(tmpl, newp, append, appendsz, NULL, &tmpl->cbtxn->sigops_))
 		return -3;
 	tmpl->cbtxn->datasz += appendsz;
+	tmpl->cbtxn->weight += appendsz * 4;
 	
 	return availsz;
 }
diff --git a/blkmaker_jansson.c b/blkmaker_jansson.c
index b24a7f8..ceedca1 100644
--- a/blkmaker_jansson.c
+++ b/blkmaker_jansson.c
@@ -306,6 +306,7 @@ const char *blktmpl_add_jansson(blktemplate_t *tmpl, const json_t *json, time_t
 	my_flip(tmpl->prevblk, 32);
 	GETNUM_O(sigoplimit, unsigned short);
 	GETNUM_O(sizelimit, unsigned long);
+	GETNUM_O(weightlimit, int64_t);
 	GETNUM(version, uint32_t);
 	
 	if ((v = json_object_get(json, "mutable")) && json_is_array(v))
@@ -408,6 +409,7 @@ const char *blktmpl_add_jansson(blktemplate_t *tmpl, const json_t *json, time_t
 	tmpl->txns = calloc(txns, sizeof(*tmpl->txns));
 	tmpl->txns_datasz = 0;
 	tmpl->txns_sigops = 0;
+	tmpl->txns_weight = 0;
 	for (size_t i = 0; i < txns; ++i)
 	{
 		struct blktxn_t * const txn = &tmpl->txns[i];
@@ -422,6 +424,13 @@ const char *blktmpl_add_jansson(blktemplate_t *tmpl, const json_t *json, time_t
 		} else {
 			tmpl->txns_sigops += txn->sigops_;
 		}
+		if (tmpl->txns_weight == -1) {
+			;  // Impossible to tally the unknown
+		} else if (txn->weight == -1) {
+			tmpl->txns_weight = -1;
+		} else {
+			tmpl->txns_weight += txn->weight;
+		}
 	}
 	
 	if ((v = json_object_get(json, "coinbasetxn")) && json_is_object(v))
diff --git a/blktemplate.h b/blktemplate.h
index 563ae7f..5c19fc0 100644
--- a/blktemplate.h
+++ b/blktemplate.h
@@ -156,6 +156,8 @@ typedef struct {
 	bool _bip141_sigops;
 	bool _calculated_witness;
 	libblkmaker_hash_t *_witnessmrklroot;
+	int64_t weightlimit;
+	int64_t txns_weight;
 } blktemplate_t;
 
 extern void blktxn_init(struct blktxn_t *);