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author | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2014-03-25 22:37:19 -0700 |
commit | 1bc5aee63eb72b341f506ad058502cd0361f0d10 (patch) | |
tree | c607e8252f3405424ff15bc2d00aa38dadbb2518 /gcc-4.9/libgo/go/html/template/error.go | |
parent | 283a0bf58fcf333c58a2a92c3ebbc41fb9eb1fdb (diff) | |
download | toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.gz toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.tar.bz2 toolchain_gcc-1bc5aee63eb72b341f506ad058502cd0361f0d10.zip |
Initial checkin of GCC 4.9.0 from trunk (r208799).
Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba
Diffstat (limited to 'gcc-4.9/libgo/go/html/template/error.go')
-rw-r--r-- | gcc-4.9/libgo/go/html/template/error.go | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/gcc-4.9/libgo/go/html/template/error.go b/gcc-4.9/libgo/go/html/template/error.go new file mode 100644 index 000000000..46e49ccf8 --- /dev/null +++ b/gcc-4.9/libgo/go/html/template/error.go @@ -0,0 +1,197 @@ +// Copyright 2011 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package template + +import ( + "fmt" +) + +// Error describes a problem encountered during template Escaping. +type Error struct { + // ErrorCode describes the kind of error. + ErrorCode ErrorCode + // Name is the name of the template in which the error was encountered. + Name string + // Line is the line number of the error in the template source or 0. + Line int + // Description is a human-readable description of the problem. + Description string +} + +// ErrorCode is a code for a kind of error. +type ErrorCode int + +// We define codes for each error that manifests while escaping templates, but +// escaped templates may also fail at runtime. +// +// Output: "ZgotmplZ" +// Example: +// <img src="{{.X}}"> +// where {{.X}} evaluates to `javascript:...` +// Discussion: +// "ZgotmplZ" is a special value that indicates that unsafe content reached a +// CSS or URL context at runtime. The output of the example will be +// <img src="#ZgotmplZ"> +// If the data comes from a trusted source, use content types to exempt it +// from filtering: URL(`javascript:...`). +const ( + // OK indicates the lack of an error. + OK ErrorCode = iota + + // ErrAmbigContext: "... appears in an ambiguous URL context" + // Example: + // <a href=" + // {{if .C}} + // /path/ + // {{else}} + // /search?q= + // {{end}} + // {{.X}} + // "> + // Discussion: + // {{.X}} is in an ambiguous URL context since, depending on {{.C}}, + // it may be either a URL suffix or a query parameter. + // Moving {{.X}} into the condition removes the ambiguity: + // <a href="{{if .C}}/path/{{.X}}{{else}}/search?q={{.X}}"> + ErrAmbigContext + + // ErrBadHTML: "expected space, attr name, or end of tag, but got ...", + // "... in unquoted attr", "... in attribute name" + // Example: + // <a href = /search?q=foo> + // <href=foo> + // <form na<e=...> + // <option selected< + // Discussion: + // This is often due to a typo in an HTML element, but some runes + // are banned in tag names, attribute names, and unquoted attribute + // values because they can tickle parser ambiguities. + // Quoting all attributes is the best policy. + ErrBadHTML + + // ErrBranchEnd: "{{if}} branches end in different contexts" + // Example: + // {{if .C}}<a href="{{end}}{{.X}} + // Discussion: + // Package html/template statically examines each path through an + // {{if}}, {{range}}, or {{with}} to escape any following pipelines. + // The example is ambiguous since {{.X}} might be an HTML text node, + // or a URL prefix in an HTML attribute. The context of {{.X}} is + // used to figure out how to escape it, but that context depends on + // the run-time value of {{.C}} which is not statically known. + // + // The problem is usually something like missing quotes or angle + // brackets, or can be avoided by refactoring to put the two contexts + // into different branches of an if, range or with. If the problem + // is in a {{range}} over a collection that should never be empty, + // adding a dummy {{else}} can help. + ErrBranchEnd + + // ErrEndContext: "... ends in a non-text context: ..." + // Examples: + // <div + // <div title="no close quote> + // <script>f() + // Discussion: + // Executed templates should produce a DocumentFragment of HTML. + // Templates that end without closing tags will trigger this error. + // Templates that should not be used in an HTML context or that + // produce incomplete Fragments should not be executed directly. + // + // {{define "main"}} <script>{{template "helper"}}</script> {{end}} + // {{define "helper"}} document.write(' <div title=" ') {{end}} + // + // "helper" does not produce a valid document fragment, so should + // not be Executed directly. + ErrEndContext + + // ErrNoSuchTemplate: "no such template ..." + // Examples: + // {{define "main"}}<div {{template "attrs"}}>{{end}} + // {{define "attrs"}}href="{{.URL}}"{{end}} + // Discussion: + // Package html/template looks through template calls to compute the + // context. + // Here the {{.URL}} in "attrs" must be treated as a URL when called + // from "main", but you will get this error if "attrs" is not defined + // when "main" is parsed. + ErrNoSuchTemplate + + // ErrOutputContext: "cannot compute output context for template ..." + // Examples: + // {{define "t"}}{{if .T}}{{template "t" .T}}{{end}}{{.H}}",{{end}} + // Discussion: + // A recursive template does not end in the same context in which it + // starts, and a reliable output context cannot be computed. + // Look for typos in the named template. + // If the template should not be called in the named start context, + // look for calls to that template in unexpected contexts. + // Maybe refactor recursive templates to not be recursive. + ErrOutputContext + + // ErrPartialCharset: "unfinished JS regexp charset in ..." + // Example: + // <script>var pattern = /foo[{{.Chars}}]/</script> + // Discussion: + // Package html/template does not support interpolation into regular + // expression literal character sets. + ErrPartialCharset + + // ErrPartialEscape: "unfinished escape sequence in ..." + // Example: + // <script>alert("\{{.X}}")</script> + // Discussion: + // Package html/template does not support actions following a + // backslash. + // This is usually an error and there are better solutions; for + // example + // <script>alert("{{.X}}")</script> + // should work, and if {{.X}} is a partial escape sequence such as + // "xA0", mark the whole sequence as safe content: JSStr(`\xA0`) + ErrPartialEscape + + // ErrRangeLoopReentry: "on range loop re-entry: ..." + // Example: + // <script>var x = [{{range .}}'{{.}},{{end}}]</script> + // Discussion: + // If an iteration through a range would cause it to end in a + // different context than an earlier pass, there is no single context. + // In the example, there is missing a quote, so it is not clear + // whether {{.}} is meant to be inside a JS string or in a JS value + // context. The second iteration would produce something like + // + // <script>var x = ['firstValue,'secondValue]</script> + ErrRangeLoopReentry + + // ErrSlashAmbig: '/' could start a division or regexp. + // Example: + // <script> + // {{if .C}}var x = 1{{end}} + // /-{{.N}}/i.test(x) ? doThis : doThat(); + // </script> + // Discussion: + // The example above could produce `var x = 1/-2/i.test(s)...` + // in which the first '/' is a mathematical division operator or it + // could produce `/-2/i.test(s)` in which the first '/' starts a + // regexp literal. + // Look for missing semicolons inside branches, and maybe add + // parentheses to make it clear which interpretation you intend. + ErrSlashAmbig +) + +func (e *Error) Error() string { + if e.Line != 0 { + return fmt.Sprintf("html/template:%s:%d: %s", e.Name, e.Line, e.Description) + } else if e.Name != "" { + return fmt.Sprintf("html/template:%s: %s", e.Name, e.Description) + } + return "html/template: " + e.Description +} + +// errorf creates an error given a format string f and args. +// The template Name still needs to be supplied. +func errorf(k ErrorCode, line int, f string, args ...interface{}) *Error { + return &Error{k, "", line, fmt.Sprintf(f, args...)} +} |