internal/pkg: highlight cache verbose output

This highlights sections of messages, increasing readability in some cases.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/pkg.go

@@ -779,6 +779,8 @@ type Cache struct {
 	wg sync.WaitGroup
 	// Reports new cures and passed to [Artifact].
 	msg message.Msg
+	// Select graphics rendition sequences, populated by Open.
+	sgrRes, sgrIdent, sgrWarn, sgrErr string
 
 	// Directory where all [Cache] related files are placed.
 	base *check.Absolute
@@ -1511,10 +1513,10 @@ func (c *Cache) openFile(
 		id := c.Ident(f)
 		if c.msg.IsVerbose() {
 			rn := reportName(f, id)
-			c.msg.Verbosef("curing %s in memory...", rn)
+			c.msg.Verbosef("curing %s%s%s in memory...", c.sgrIdent, rn, c.sgrRes)
 			defer func() {
 				if err == nil {
-					c.msg.Verbosef("opened %s for reading", rn)
+					c.msg.Verbosef("opened %s%s%s for reading", c.sgrIdent, rn, c.sgrRes)
 				}
 			}()
 		}
@@ -1893,7 +1895,10 @@ func (mr *measuredReader) Close() (err error) {
 	}
 
 	if n > 0 {
-		mr.c.msg.Verbosef("missed %d bytes on measured reader", n)
+		mr.c.msg.Verbosef(
+			"%smissed %d bytes on measured reader%s",
+			mr.c.sgrWarn, n, mr.c.sgrRes,
+		)
 	}
 
 	if err = mr.r.Close(); err != nil {
@@ -2154,8 +2159,9 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 				)
 				if errors.Is(err, os.ErrExist) {
 					c.msg.Verbosef(
-						"creating alternative over %s for artifact %s",
+						"creating alternative over %s%s%s for artifact %s%s%s",
-						Encode(substitute.Value()), ids,
+						c.sgrIdent, Encode(substitute.Value()), c.sgrRes,
+						c.sgrIdent, ids, c.sgrRes,
 					)
 					err = nil
 				}
@@ -2198,15 +2204,18 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 	whence = WNew
 	if c.msg.IsVerbose() {
 		rn := reportName(a, id)
-		c.msg.Verbosef("curing %s...", rn)
+		c.msg.Verbosef("curing %s%s%s...", c.sgrIdent, rn, c.sgrRes)
 		defer func() {
 			if err != nil {
 				return
 			}
 			if checksums != "" {
-				c.msg.Verbosef("cured %s checksum %s", rn, checksums)
+				c.msg.Verbosef(
+					"cured %s%s%s checksum %s%s%s",
+					c.sgrIdent, rn, c.sgrRes,
+					c.sgrIdent, checksums, c.sgrRes)
 			} else {
-				c.msg.Verbosef("cured %s", rn)
+				c.msg.Verbosef("cured %s%s%s", c.sgrIdent, rn, c.sgrRes)
 			}
 		}()
 	}
@@ -2301,7 +2310,11 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 		c.exitCure(a, curesExempt)
 		if err != nil {
 			if c.msg.IsVerbose() {
-				c.msg.Verbosef("cure file %s: %v", reportName(f, id), err)
+				c.msg.Verbosef(
+					"cure file %s%s%s: %s%v%s",
+					c.sgrIdent, reportName(f, id), c.sgrRes,
+					c.sgrErr, err, c.sgrRes,
+				)
 			}
 			return
 		}
@@ -2348,7 +2361,11 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 		c.exitCure(a, curesExempt)
 		if err != nil {
 			if c.msg.IsVerbose() {
-				c.msg.Verbosef("cure trivial %s: %v", reportName(ca, id), err)
+				c.msg.Verbosef(
+					"cure trivial %s%s%s: %s%v%s",
+					c.sgrIdent, reportName(ca, id), c.sgrRes,
+					c.sgrErr, err, c.sgrRes,
+				)
 			}
 			return
 		}
@@ -2358,7 +2375,11 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 		var externChecksum unique.Handle[Checksum]
 		if externChecksum, err = c.tryExtern(ctx, id); err != nil {
 			if c.msg.IsVerbose() {
-				c.msg.Verbosef("extern %s: %v", reportName(ca, id), err)
+				c.msg.Verbosef(
+					"extern %s%s%s: %s%v%s",
+					c.sgrIdent, reportName(ca, id), c.sgrRes,
+					c.sgrErr, err, c.sgrRes,
+				)
 			}
 			return
 		}
@@ -2398,8 +2419,8 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 					if sum == zeroChecksum {
 						if c.msg.IsVerbose() {
 							c.msg.Verbosef(
-								"input %s not available",
+								"input %s%s%s not available",
-								reportName(d, did),
+								c.sgrIdent, reportName(d, did), c.sgrRes,
 							)
 						}
 						err = HangingInputError(did)
@@ -2463,7 +2484,11 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 			if checksum != zeroChecksum && externChecksum != checksum {
 				err = &ChecksumMismatchError{externChecksum.Value(), checksum.Value()}
 				if c.msg.IsVerbose() {
-					c.msg.Verbosef("extern %s: %v", reportName(ca, id), err)
+					c.msg.Verbosef(
+						"extern %s%s%s: %s%v%s",
+						c.sgrIdent, reportName(ca, id), c.sgrRes,
+						c.sgrErr, err, c.sgrRes,
+					)
 				}
 				return
 			}
@@ -2512,7 +2537,11 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 		}
 		if err != nil {
 			if c.msg.IsVerbose() {
-				c.msg.Verbosef("cure %s: %v", reportName(ca, id), err)
+				c.msg.Verbosef(
+					"cure %s%s%s: %s%v%s",
+					c.sgrIdent, reportName(ca, id), c.sgrRes,
+					c.sgrErr, err, c.sgrRes,
+				)
 			}
 			return
 		}
@@ -2563,7 +2592,11 @@ func (c *Cache) cure(a Artifact, curesExempt, rebuild bool) (
 			Want: checksum.Value(),
 		}
 		if c.msg.IsVerbose() {
-			c.msg.Verbosef("validate %s: %v", reportName(a, id), err)
+			c.msg.Verbosef(
+				"validate %s%s%s: %s%v%s",
+				c.sgrIdent, reportName(a, id), c.sgrRes,
+				c.sgrErr, err, c.sgrRes,
+			)
 		}
 		return
 	}
@@ -2898,6 +2931,13 @@ func Open(
 		return nil, UnsupportedVariantError(s)
 	}
 
+	if a.Flags&CColourOutput != 0 {
+		c.sgrRes = "\x1b[0m"
+		c.sgrIdent = "\x1b[1m"
+		c.sgrWarn = "\x1b[35m"
+		c.sgrErr = "\x1b[1;31m"
+	}
+
 	return &c, nil
 }