dbQuoteLiteral() works for difftime objects

DESCRIPTION

@@ -41,7 +41,7 @@ VignetteBuilder:
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE, roclets = c("collate",
     "namespace", "rd"))
-RoxygenNote: 7.1.1
+RoxygenNote: 7.1.1.9000
 Collate: 
     'hidden.R'
     'DBObject.R'
@@ -55,6 +55,7 @@ Collate:
     'data-types.R'
     'data.R'
     'deprecated.R'
+    'hms.R'
     'interpolate.R'
     'list-pairs.R'
     'quote.R'

R/hms.R

@@ -0,0 +1,98 @@
+# from hms
+format_hms <- function(x) {
+  units(x) <- "secs"
+  xx <- decompose(x)
+
+  ifelse(is.na(x), NA_character_, paste0(
+    ifelse(xx$sign, "-", ""),
+    format_hours(xx$hours), ":",
+    format_two_digits(xx$minute_of_hour), ":",
+    format_two_digits(xx$second_of_minute),
+    format_tics(xx$tics)))
+}
+
+format_hours <- function(x) {
+  # Difference to hms: don't justify here
+  format_two_digits(x)
+}
+
+format_two_digits <- function(x) {
+  formatC(x, format = "f", digits = 0, width = 2, flag = "0")
+}
+
+format_tics <- function(x) {
+  x <- x / TICS_PER_SECOND
+
+  out <- format(x, scientific = FALSE, digits = SPLIT_SECOND_DIGITS + 1L)
+  digits <- max(min(max(nchar(out) - 2), SPLIT_SECOND_DIGITS), 0)
+  out <- formatC(x, format = "f", digits = digits)
+  gsub("^0", "", out)
+}
+
+SPLIT_SECOND_DIGITS <- 6L
+
+TICS_PER_SECOND <- 10^SPLIT_SECOND_DIGITS
+SECONDS_PER_MINUTE <- 60
+MINUTES_PER_HOUR <- 60
+HOURS_PER_DAY <- 24
+
+TICS_PER_MINUTE <- SECONDS_PER_MINUTE * TICS_PER_SECOND
+TICS_PER_HOUR <- MINUTES_PER_HOUR * TICS_PER_MINUTE
+TICS_PER_DAY <- HOURS_PER_DAY * TICS_PER_HOUR
+
+days <- function(x) {
+  trunc(x / TICS_PER_DAY)
+}
+
+hours <- function(x) {
+  trunc(x / TICS_PER_HOUR)
+}
+
+hour_of_day <- function(x) {
+  abs(hours(x) - days(x) * HOURS_PER_DAY)
+}
+
+minutes <- function(x) {
+  trunc(x / TICS_PER_MINUTE)
+}
+
+minute_of_hour <- function(x) {
+  abs(minutes(x) - hours(x) * MINUTES_PER_HOUR)
+}
+
+seconds <- function(x) {
+  trunc(x / TICS_PER_SECOND)
+}
+
+second_of_minute <- function(x) {
+  abs(seconds(x) - minutes(x) * SECONDS_PER_MINUTE)
+}
+
+tics <- function(x) {
+  x
+}
+
+tic_of_second <- function(x) {
+  abs(tics(x) - seconds(x) * TICS_PER_SECOND)
+}
+
+decompose <- function(x) {
+  x <- unclass(x) * TICS_PER_SECOND
+
+  # #140
+  xr <- round(x)
+
+  out <- list(
+    sign = xr < 0 & !is.na(xr),
+    hours = abs(hours(xr)),
+    minute_of_hour = minute_of_hour(xr),
+    second_of_minute = second_of_minute(xr),
+    tics = tic_of_second(xr)
+  )
+
+  # #140: Make sure zeros are printed
+  fake_zero <- (out$tics == 0) & (xr != x)
+  out$tics[fake_zero] <- 0.25
+
+  out
+}

R/quote.R

@@ -370,6 +370,8 @@ setMethod("dbQuoteLiteral", signature("DBIConnection"),
 
     if (inherits(x, "Date")) return(dbQuoteString(conn, as.character(x)))
 
+    if (inherits(x, "difftime")) return(dbQuoteString(conn, format_hms(x)))
+
     if (is.list(x)) {
       blob_data <- vapply(
         x,